On Spring

Overview

• Spring projects
• Spring documentation (quick access to API and reference documentation for all Spring projects)

• Raising Spring: An 18-Year Journey (Rod Johnson, Oct. 24, 19)

Spring Framework

• http://www.springsource.org/spring-framework
• Desc. : provides a comprehensive programming and configuration model for modern Java-based enterprise applications - on any kind of deployment platform.
• License :
• Sources : https://github.com/spring-projects/spring-framework
• Maven artifacts
  • org.springframework

References

• Spring Framework 5.3 Reference Documentation
• Spring Framework 5.3 API
• Spring Framework 5.0 Reference Documentation
• Spring Framework 5.0 API
• Spring Framework 4.3 Reference Documentation
• Spring Framework 4.3 API
• Spring Framework 4.2 Reference Documentation
• Spring Framework 4.2 API
• Spring Framework 4.1 Reference Documentation
• Spring Framework 4.1 API
• Spring Framework 4.0 Reference Documentation
• Spring Framework 4.0 API
• Spring Framework 3.2 Reference Documentation
• Spring Framework 3.2 API
• Spring Framework 3.1 Reference Documentation
• Spring Framework 3.1 API
• Spring Framework 3.0 Reference Documentation
• Spring Framework 3.0 API

• Spring 5 Tutorial

General

• Inversion of Control Containers and the Dependency Injection pattern(Martin Fowler, 23 January 2004)
• Announcing Spring Framework 4.0 GA Release
  • Press release
• Setter injection versus constructor injection and the use of @Required(JULY 11, 2007)
  • As of Spring 3.1, the Spring team generally advocates setter injection. because ...
  • As of Spring 4.0, the Spring team generally advocates constructor injection as it enables ...

Notes

• Annotation injection is performed before XML injection, thus the latter configuration will override the former for properties wired through both approaches.
• The @Required annotation simply indicates that the affected bean property must be populated at configuration time, through an explicit property value in a bean definition or through autowiring. The container throws an exception if the affected bean property has not been populated; this allows for eager and explicit failure, avoiding NullPointerExceptions or the like later on. It is still recommended that you put assertions into the bean class itself, for example, into an init method. Doing so enforces those required references and values even when you use the class outside of a container.

Resource

• Resource strings

Prefix	Example	Remarks
classpath:	classpath:com/myapp/config.xml
file:	file:///data/config.xml
http:	https://myserver/logo.png

Class/Interface	Description	Remarks
Resource	Interface for a resource descriptor that abstracts from the actual type of underlying resource, such as a file or class path resource.
ClassPathResource	Resource implementation for class path resources.
FileSystemResource	Resource implementation for java.io.File and java.nio.file.Path handles with a file system target.
ResourceUtils	Utility methods for resolving resource locations to files in the file system.

• Wildcards in application context constructor resource paths
  • classpath*:, classpath:com/mycompany/**/applicationContext.xml, ...

Container

• ApplicationContext

  EnvironmentCapable <--------------------------------+
                                                      |
  BeanFactory <--+--- ListableBeanFactory ------------+                 LifeCycle <-------------+
                 |                                    |                                         |
                 +--- HierarchicalBeanFactory --------+                                         |
                                                      +--- ApplicationContext <---- ConfigurableApplicationContext
  MessageSource <-------------------------------------+
                                                      |
  ApplicationEventPublisher <-------------------------+
                                                      |
  ResourceLoader <---- ResourcePatternResolver <------+

Interface	Description	Methods	Remarks
ApplicationContext	Central interface to provide configuration for an application.		read-only while the application is running
EnvironmentCapable	indicating a component that contains and exposes an Environment reference.	getEnvironment()	Environment
ListableBeanFactory	Extension of the BeanFactory interface to be implemented by bean factories that can enumerate all their bean instances, rather than attempting bean lookup by name one by one as requested by clients.	getBeanDefinitionNames(), getBeanNamesForType(), getBeanNamesForAnnotation()
MessageSource	Strategy interface for resolving messages, with support for the parameterization and internationalization of such messages.	getMessage()	ReloadableResourceBundleMessageSource
ResourcePatternResolver	Strategy interface for resolving a location pattern (for example, an Ant-style path pattern) into Resource objects.	getResources(String pattern), getResource()

• ConfigurableApplicationContext
  • Prefer ConfigurableApplicationContext to ApplicationContext
  • Pay attention to registerShutdownHook() method.
• GenericXmlApplicationContext

 
  DefaultResourceLoader
         |
         +----- AbstractApplicationContext
         |           |
         |           +----- AbstractRefreshableApplicationContext
         |                       |
         |                       +----- AbstractRefreshableConfigApplicationContext
         |                                   |
         |                                   +----- AbstractRefreshableWebApplicationContext
         |                                   |           |
         |                                   |           +----- AnnotationConfigWebApplicationContext 
         |                                   |           +----- GroovyWebApplicationContext
         |                                   |           +----- XmlWebApplicationContext
         |                                   |
         |                                   +----- AbstractXmlApplicationContext
         |                                   |           |
         |                                   |           +------- ClassPathXmlApplicationContext
         |                                   |           +------- FileSystemXmlApplicationContext
         |                                   |
         |                                   +----- AnnotationConfigReactiveWebApplicationContext
         +----- GenericApplicationContext
                     |
                     +----- AnnotationConfigApplicationContext
                     +----- GenericGroovyApplicationContext
                     +----- GenericReactiveWebApplicationContext
                     |           |
                     |           +----- ReactiveWebServerApplicationContext
                     |                       |
                     |                       +----- AnnotationConfigReactiveWebServerApplicationContext 
                     |
                     +----- GenericWebApplicationContext
                     |           |
                     |           +----- ServletWebServerApplicationContext
                     |                       |
                     |                       +----- AnnotationConfigServletWebServerApplicationContext
                     |                       +----- XmlServletWebServerApplicationContext
                     |
                     +----- GenericXmlApplicationContext
                     +----- ResourceAdapterApplicationContext
                     +----- StaticApplicationContext
                                 |
                                 +----- StaticWebApplicationContext

Configuration

• Annotation-based Container Configuration
  • @Required, @Autowired, @Inject, @Named
  • Annotation injection is performed before XML injection. Thus, the XML configuration overrides the annotations for properties wired through both approaches.
  • The @Required annotation is formally deprecated as of Spring Framework 5.1, in favor of using constructor injection for required settings.

• Java-based Container Configuration
  • @Configuration, @Bean, @PropertySource
  • The @Bean annotation is used to indicate that a method instantiates, configures, and initializes a new object to be managed by the Spring IoC container.
  • The @Bean annotation plays the same role as the <bean/> element.
  • Annotating a class with @Configuration indicates that its primary purpose is as a source of bean definitions.

• Spring Component Scan Include and Exclude Filter Example (June 24, 2019)

API

Annotation	Package	Annotations	Remarks
@Configuration	o.s.context.annotation	Indicates that a class declares one or more @Bean methods and may be processed by the Spring container to generate bean definitions and service requests for those beans at runtime.	@Component
@ComponentScan	o.s.context.annotation	Configures component scanning directives for use with @Configuration classes.	<context:component-scan>
@Import	o.s.context.annotation	Indicates one or more @Configuration classes to import.
@EnableAsync	o.s.scheduling.annotation	Enables Spring's asynchronous method execution capability.	@Async
@EnableScheduling	o.s.scheduling.annotation	Enables Spring's scheduled task execution capability.	@Scheduled
@SpringBootApplication	o.s.boot.autoconfigure	Indicates a configuration class that declares one or more @Bean methods and also triggers auto-configuration and component scanning	@Configuration, @EnableAutoConfiguration, @ComponentScan
@EnableAutoConfiguration	o.s.boot.autoconfigure	Enable auto-configuration of the Spring Application Context, attempting to guess and configure beans that you are likely to need.	exclude, excludeName

Properties

• Properties with Spring(October 15, 2013)
• Example: the Class name substitution PropertyPlaceholderConfigurer
• Using Spring and Commons Configuration (Jul 11th, 2008)
• Nested Property Placeholders in Spring Configuration (February 25, 2008)
• How to programmatically resolve property placeholder in Spring(Mar 2 '11)
• Bean definition profiles
• Not loading a Spring bean when a certain profile is set (Aug 1 '14)
• Encrypting application configuration files using Jasypt

API

Item	Type	Description	Remarks
PropertyPlaceholderConfigurer	class
PropertySourcesPlaceholderConfigurer	class
PropertiesLoaderSupport.setLocalOverride(boolean localOverride)	method
EmbeddedValueResolverAware	class
propertyPlaceholder type	XML
property-placeholder element	XML

Benas

• MethodInvokingFactoryBean
  • returns a value which is the result of a static or instance method invocation.
• MethodInvokingBean
  • just invoking a target method, not expecting a result to expose to the container.

  <bean id="registeringIdentificationListener" class="org.springframework.beans.factory.config.MethodInvokingBean"
    depends-on="listenableDetectionService, defaultDetectionListener">
    <property name="targetObject" ref="listenableDetectionService"/>
    <property name="targetMethod" value="addListener"/>
    <property name="arguments" ref="defaultDetectionListener"/>
  </bean>

• Wiring collections
  • <list/>, <set/>, , and <props/>
• Declaring an array of objects in a Spring bean context(Aug 31 '10)
• Using MethodInvokingFactoryBean to set up unconventional beans(Mar 23 '11)

• Spring Annotation Programming Model (8 Jun 2016)
• @Required
• @Autowired
• @Resource
  • javax.annotation.Resource API
• @Inject and @Named
• Spring annotations vs. Standard annotations
  • @Autowired, @Component, @Component, @Inject, @Required, ...
• Spring Injection with @Resource, @Autowired and @Inject (2011)
• Combining lifecycle mechanisms using @PostConstruct and @PreDestroy
  • javax.annotation package of Java SE 6 (contains @PostConstruct, @PreDestroy and @Resource)
• Spring: Using @Qualifier with Property Placeholder (Aug 13 '13)
  • @Resource(name="${qualifier}")

• Bean Lifecycle Callbacks
  • Initializing : @PostConstruct methods -> InitializingBean.afterPropertiesSet() -> bean@init-method
  • Destroying : @PreDestroy methods -> DisposableBean.destroy() -> bean@destroy-method

API

Class	Package	Description	Remarks
@Bean	o.s.context.annotation	Indicates that a method produces a bean to be managed by the Spring container.	@Configuration
@Component	o.s.stereotype	Indicates that an annotated class is a "component". Such classes are considered as candidates for auto-detection when using annotation-based configuration and classpath scanning.	@ComponentScan
@Required	o.s.beans.factory.annotation	Marks a method (typically a JavaBean setter method) as being 'required': that is, the setter method must be configured to be dependency-injected with a value.	Deprecated as of 5.1
@Autowired	o.s.beans.factory.annotation	Marks a constructor, field, setter method, or config method as to be autowired by Spring's dependency injection facilities.	JSR-330 @Inject
@Primary	o.s.context.annotation	Indicates that a bean should be given preference when multiple candidates are qualified to autowire a single-valued dependency.
@Qualifier	o.s.beans.factory.annotation	This annotation may be used on a field or parameter as a qualifier for candidate beans when autowiring.
@Resource	javax.annotation	The Resource annotation marks a resource that is needed by the application.	@Autowired
@ManagedBean	javax.annotation	The ManagedBean annotation marks a POJO as a ManagedBean.A ManagedBean supports a small set of basic services such as resource injection, lifecycle callbacks and interceptors.	@Component
@Named	javax.inject	String-based qualifier.
@Inject	javax.inject	Identifies injectable constructors, methods, and fields.	@Autowired
@Scope
@Lazy
@PostConstruct	javax.annotation	used on a method that needs to be executed after dependency injection is done to perform any initialization.
@PreDestroy	javax.annotation	used on a method as a callback notification to signal that the instance is in the process of being removed by the container.
@Conditional	o.s.context.annotation	Indicates that a component is only eligible for registration when all specified conditions match.
@Profile	o.s.context.annotation	Indicates that a component is eligible for registration when one or more specified profiles are active.
@ConditionalOnProperty	o.s.b.autoconfigure.condition	Conditional that checks if the specified properties have a specific value.

Annotations

Purpose	Package	Annotations
Denoting the roles of types or methods in the overall architecture	o.s.stereotype	@Component, @Controller, @Repository, @Service
Bean configuration	o.s.beans.factory.annotation	@Autowired, @Required, @Value, ...
ApplicationContext support	o.s.context.annotation	@Bean, @ComponentScan, @Conditional, @Configuration, @Lazy, @Profile, @Scope, ...
Asynchronous method execution	o.s.scheduling.annotation	@Async, @Scheduled
Binding requests to controllers and handler methods	o.s.web.bind.annotation	@RestController, @GetMapping, @PostMapping, @PutMapping, @PathVariable, @RequestBody, @ResponseBody, ...
Transaction demarcation	o.s.transaction.annotation	@Transactional, @EnableTransactionManagement
Annotation-driven tests	o.s.test.annotation	@IfProfileValue, @Repeat, @Rollback, @Timed
MBean exposure	o.s.jmx.export.annotation	@ManagedResource, @ManagedAttribute, @ManagedOperation
Declaratively configuring field formatting rules	o.s.format.annotation	@DateTimeFormat, @NumberFormat
Spring Boot's auto-configuration capabilities.	o.s.boot.autoconfigure	@EnableAutoConfiguration, @SpringBootApplication

SpEL

• Expression support for defining bean definitions
• Escaping Spring EL (2010)
• SpEL Predefined Variables (12-May-2011)
• SpEL
• How do I reference a bean in spring-el named with a prefix? (Jul 9 '13)

Transaction

• Using @Transactional
  • "Spring recommends that you only annotate concrete classes (and methods of concrete classes) with the @Transactional annotation, as opposed to annotating interfaces."
  • "When using proxies, you should apply the @Transactional annotation only to methods with public visibility."
  • "In proxy mode (which is the default), only external method calls coming in through the proxy are intercepted. This means that self-invocation, in effect, a method within the target object calling another method of the target object, will not lead to an actual transaction at runtime even if the invoked method is marked with @Transactional."
  • "@EnableTransactionManagement and <tx:annotation-driven/> only looks for @Transactional on beans in the same application context they are defined in."
  • Annotation driven transaction settings
  • Use aspectj mode as possible.
• Using @Transactional with AspectJ
• SPRING DECLARATIVE TRANSACTION MANAGEMENT WITH JDK PROXY VS ASPECTJ(28 JUNE, 2014)
  • Use compile-time weaving (not load-time weaving) with @aspectj@ mode to processing @Transactional annotations.
• Distributed transactions in Spring, with and without XA
• XA transactions using Spring
• J2EE Without the Application Server
• Configuring Spring and JTA without full Java EE
• Understanding transaction pitfalls(February 03, 2009)
• Interesting points about the use of Spring Transactional (Jun 10, 2016)
  • Spring does not support transactions propagation across remote calls
  • Spring does not support self-invocation by default
  • Spring only supports transactions in public methods

API

Class	Description	Remarks
@Transactional	Describes transaction attributes on a method or class.
@TransactionConfiguration	Defines class-level metadata for configuring transactional tests.
@Rollback	Indicate whether or not the transaction for the annotated test method should be rolled back after the test method has completed.

AOP

• Load-time weaving with AspectJ in the Spring Framework

Concurrency

• Task Execution and Scheduling
• 4 ways to schedule tasks in Spring 3 : @Scheduled example (April 23, 2013)
• How to parameterize @Scheduled(fixedDelay) with Spring 3.0 expression language? (Apr 8 '10)

API

Class	Description	Remarks
TaskExecutor	Simple task executor interface that abstracts the execution of a Runnable.
ExecutorServiceAdapter	Adapter that takes a Spring TaskExecutor and exposes a full java.util.concurrent.ExecutorService for it.
ConcurrentTaskExecutor	Adapter that takes a java.util.concurrent.Executor and exposes a Spring TaskExecutor for it.
ThreadPoolTaskExecutor	JavaBean that allows for configuring a ThreadPoolExecutor in bean style (through its "corePoolSize", "maxPoolSize", "keepAliveSeconds", "queueCapacity" properties) and exposing it as a Spring TaskExecutor.
ThreadPoolExecutorFactoryBean	JavaBean that allows for configuring a ThreadPoolExecutor in bean style (through its "corePoolSize", "maxPoolSize", "keepAliveSeconds", "queueCapacity" properties) and exposing it as a bean reference of its native ExecutorService type.
@Scheduled
@Async

Internationalization

• Internationalization using MessageSource
• Spring Resource bundle with ResourceBundleMessageSource example (August 30, 2012)

API

Class	Description	Remarks
o.s.context.MessageSource
o.s.context.support.ResourceBundleMessageSource
o.s.context.support.ReloadableResourceBundleMessageSource

Source

• AbstractMessageSource.getMessageInternal()

Web MVC

• Read HTTP Request Header in Spring MVC
  • @RequestHeader
• Spring MVC - Binding HTTP request header attributes with @RequestHeader (Feb 17, 2016)
• How to Set a Header on a Response with Spring 5 (February 21, 2019)
• Spring MVC @RequestBody @ResponseBody Example (August 11, 2015)

API

Class	Package	Description	Remarks
HttpHeaders	javax.ws.rs.core	An injectable interface that provides access to HTTP header information.
HttpHeaders	o.s.http	A data structure representing HTTP request or response headers.
HttpHeaders	org.apache.http	Constants enumerating the HTTP headers.	RFC1945 (HTTP/1.0), RFC2616 (HTTP/1.1), RFC2518 (WebDAV)
MediaType	javax.ws.rs.core	An abstraction for a media type.
MediaType	o.s.http
ContentType	org.apache.http.entity	Content type information consisting of a MIME type and an optional charset.
HttpEntity<T>	o.s.http
RequestEntity<T>	o.s.http
ResponseEntity<T>	o.s.http
@RequestMapping	o.s.web.bind.annotation	Annotation for mapping web requests onto methods in request-handling classes with flexible method signatures.
@GetMapping	o.s.web.bind.annotation	Annotation for mapping HTTP GET requests onto specific handler methods.
@PostMapping	o.s.web.bind.annotation	Annotation for mapping HTTP POST requests onto specific handler methods.
@PathVariable	o.s.web.bind.annotation	Annotation which indicates that a method parameter should be bound to a URI template variable.
@RequestParam	o.s.web.bind.annotation	Annotation which indicates that a method parameter should be bound to a web request parameter.	since v2.5. In Spring MVC, "request parameters" map to query parameters, form data, and parts in multipart requests.
@RequestHeader	o.s.web.bind.annotation	Annotation which indicates that a method parameter should be bound to a web request header.
@SessionAttribute	o.s.web.bind.annotation	Annotation to bind a method parameter to a session attribute.
@RequestBody	o.s.web.bind.annotation	Annotation indicating a method parameter should be bound to the body of the web request.	since v3.0
@RequestPart	o.s.web.bind.annotation	Annotation that can be used to associate the part of a "multipart/form-data" request with a method argument.	since v3.1
CommonsRequestLoggingFilter	o.s.web.filter	Simple request logging filter that writes the request URI (and optionally the query string) to the Commons Log.

• Spring @RequestParam Annotation
  • Mapping All Parameters, Mapping a Multi-Value Parameter, ...

REST

• Spring Restfull Jax-RS annotation support (Aug 28 '14)
  • No, you cannot use javax.ws.* annotations in spring.
• Is RestTemplate thread safe? (Apr 10 '14)
  • thread-safe once constructed
• REST in Spring 3: RestTemplate (MARCH 27, 2009)
• Spring Boot RestTemplate POST JSON Example
• Spring RestTemplate - how to enable full debugging/logging of requests/responses? (Oct 31 '11)
  • logging.level.org.apache.http=DEBUG
  • logging.level.org.apache.http.wire=DEBUG

• How can we configure the internal Jackson mapper when using RestTemplate? (Feb 21 '12)

Class	Description	Remark
RestTemplate (source)	Synchronous client to perform HTTP requests, exposing a simple, template method API over underlying HTTP client libraries such as the JDK HttpURLConnection, Apache HttpComponents, and others.
HttpComponentsClientHttpRequestFactory	ClientHttpRequestFactory implementation that uses Apache HttpComponents HttpClient to create requests.
SimpleClientHttpRequestFactory	ClientHttpRequestFactory implementation that uses standard JDK facilities.
Netty4ClientHttpRequestFactory	ClientHttpRequestFactory implementation that uses Netty 4 to create requests.
HttpMessageConverter<T>
Jaxb2RootElementHttpMessageConverter	Implementation of HttpMessageConverter that can read and write XML using JAXB2.
MappingJackson2HttpMessageConverter (source)	Implementation of HttpMessageConverter that can read and write JSON using Jackson 2.x's ObjectMapper.
MappingJackson2XmlHttpMessageConverter	Implementation of HttpMessageConverter that can read and write XML using Jackson 2.x extension component for reading and writing XML encoded data.
MappingJackson2SmileHttpMessageConverter	Implementation of HttpMessageConverter that can read and write Smile data format ("binary JSON") using the dedicated Jackson 2.x extension.
Jackson2ObjectMapperBuilder	A builder used to create ObjectMapper instances with a fluent API.

Exception Handling

• Exception Handling in Spring MVC (NOVEMBER 01, 2013)
• @CONTROLLERADVICE IMPROVEMENTS IN SPRING 4 (2013/11)
• Error Handling for REST with Spring (January 23, 2017)
• org.springframework.web.servlet.handler.HandlerExceptionResolverComposite API
• org.springframework.web.servlet.handler.HandlerExceptionResolverComposite source

Filters

Class	Package	Description	Remarks
CommonsRequestLoggingFilter	o.s.web.filter	Simple request logging filter that writes the request URI (and optionally the query string) to the Commons Log.

misc

• Learn to customize Spring MVC @Controller method arguments(November 8, 2009)
• Is RestTemplate thread safe? (Apr 10 '14)
  • thread-safe once constructed

JMX

• Exporting your beans to JMX

• ManagedResource Annotation is not annoted as Inherited
  • We finally changed @ManagedResource to inherited now. Potential object name collisions need to be dealt with; the general recommendation is to not specify an object name value in @ManagedResource at all when using it on a base class.

API

• org.springframework.jmx.export.MBeanExporter
  • public void destroy() : Unregisters all beans that this exported has exposed via JMX when the enclosing ApplicationContext is destroyed.

Annotation	Package	Annotations	Remarks
@ManagedResource	o.s.jmx.export.annotation	Class-level annotation that indicates to register instances of a class with a JMX server, corresponding to the ManagedResource attribute.
@ManagedAttribute	o.s.jmx.export.annotation	Method-level annotation that indicates to expose a given bean property as a JMX attribute, corresponding to the ManagedAttribute attribute.
@ManagedOperation	o.s.jmx.export.annotation	Method-level annotation that indicates to expose a given method as a JMX operation, corresponding to the ManagedOperation attribute.

Jackson

• Jackson2ObjectMapperFactoryBean
• Latest Jackson Integration Improvements in Spring(Dec 09, 2014)

eMail

• Spring Framework 5.1 Documentation / eMail
• Spring Boot 2.1 Documentation / Sending Email
• org.springframework.boot.autoconfigure.mail.MailProperties (spring.mail)

• Guide to Spring Email (May 19, 2019)

Class/Interface	Description	Remarks
JavaMailSender	Extended MailSender interface for JavaMail, supporting MIME messages both as direct arguments and through preparation callbacks.
JavaMailSenderImpl (source)	Production implementation of the JavaMailSender interface, supporting both JavaMail MimeMessages and Spring SimpleMailMessages.	protected void doSend()
SimpleMailMessage	Models a simple mail message, including data such as the from, to, cc, subject, and text fields.
MimeMessageHelper	Helper class for populating a MimeMessage.

• Threadsafety in Javamail (Oct 4 '12)
  • Session : thread-safe, Transport : NOT thread-safe, Store :

Class/Interface	Description	Remarks
javax.mail.Session	The Session class represents a mail session and is not subclassed.	A single default session can be shared by multiple applications on the desktop. Unshared sessions can also be created.
javax.mail.Transport	An abstract class that models a message transport.

• Email (on Wikipedia)
  • Header fields
• RFC 5322 Internet Message Format

Field	Description	Remarks
From	The email address, and optionally the name of the author(s)
To	The email address(es), and optionally name(s) of the message's recipient(s)	Recipients
Cc	Carbon copy recipients
Bcc	Blind carbon copy recipients
Date	The local time and date when the message was written.
Subject	A brief summary of the topic of the message.
Content-Type	Information about how the message is to be displayed, usually a MIME type
Message-ID
In-Reply-To	Message-ID of the message that this is a reply to.
References	Message-ID of the message that this is a reply to, and the message-id of the message the previous reply was a reply to, etc.
Reply-To	Address that should be used to reply to the message.
Sender	Address of the actual sender acting on behalf of the author listed in the From: field

misc

• Nested Property Placeholders in Spring Configuration
• Spring 3 MVC and JSON example
• Spring framework p notation schema example
• Logging Dependencies in Spring
  • Using JCL, SLF4J or Log4j with Spring
• Embedded Db’s in Spring 3.0.(2011/05/02)
• Set System Property With Spring Configuration File (Jul 26 '10)

Spring Boot

• http://projects.spring.io/spring-boot/
• Desc. : makes it easy to create stand-alone, production-grade Spring based Applications that you can "just run".
• Sources : https://github.com/spring-projects/spring-boot

References

Spring Boot 2.2

• Spring Boot 2.2 Reference Documentation
• Common Application Properties

Spring Boot 2.1

• Spring Boot 2.1 Reference Guide
• Spring Boot 2.1 Actuator Web API
• Common application properties

Spring Boot 2.0

• Spring Boot 2.0 Reference Guide
• Spring Boot 2.0 API
• Spring Boot 2.0 Actuator Web API
• org.springframework.boot » spring-boot-starter-parent » 2.4.2 » pom.xml
• org.springframework.boot » spring-boot-dependencies » 2.4.1 » pom.xml
• org.springframework.boot.autoconfigure.SpringBootApplication
  • a convenience annotation that is equivalent to declaring @Configuration, @EnableAutoConfiguration and @ComponentScan
• Common application properties

Spring Boot 1.5

• Spring Boot 1.5 Reference Guide
• Spring Boot 1.5 API
• org.springframework.boot » spring-boot-starter-parent » 1.5.1 » pom.xml
• org.springframework.boot » spring-boot-dependencies » 1.5.1 » pom.xml
• spring-boot-parent/pom.xml
• spring-boot-dependencies/pom.xml

General

• GETTING STARTED Building an Application with Spring Boot
• Spring Boot without the web server (Sep 29 '14)
• How to load Spring Boot Application Context while using Cucumber at runtime, not via tests? (Nov 15 '17)

• Spring Boot 2 Tutorials
• Spring Boot 2.0 Migration Guide

Configuration

• Common application properties for Spring Boot 2.6
• Common application properties for Spring Boot 2.1
• Common application properties for Spring Boot 1.5

• Auto-configuration classes in Spring Boot 2.1
• spring.factories
  • list all Auto Configure

• Spring MVC auto-configuration
  • Converter, GenericConverter, Formatter, HttpMessageConverters , MessageCodesResolver, ConfigurableWebBindingInitializer
• Condition annotations
  • Class conditions, Bean conditions, Property conditions, Resource conditions, Web application conditions, SpEL expression conditions
  • org.springframework.boot.autoconfigure.condition package
  • ConditionalOnProperty API
• Disabling Specific Auto-configuration Classes
  • @EnableAutoConfiguration(exclude= {FreeMarkerAutoConfiguration.class})
• Multi-profile YAML Documents

• How to access a value defined in the application.properties file in Spring Boot (May 29 '15)
  • @Value, Environment, @PropertySource
• Reading application.properties in Spring Boot (April 16, 2018)
  • Read application.properties using Environment object.
  • Read a property from application.properties file using @ConfigurationProperties
  • and reading a property using the @Value annotation.

• Default value for application.properties (profile) environment placeholder cannot be comma separated (May 24 '18)
  • spring.profiles.active=${PROFILES_ACTIVE:'dev,local'}

• The @Value Annotation in Spring
  • basic form: @Value("${car.brand")
  • default valued form: @Value("${car.type:Sedan}")
  • SpEL form: @Value("#{systemProperties['user.name']}")

API

Class/Interface	Description	Remarks
WebMvcAutoConfiguration (source)	Auto-configuration for Web MVC.	localeResolver()
MessageSourceAutoConfiguration (source)	Auto-configuration for MessageSource.
Environment	Interface representing the environment in which the current application is running.

Actuator

• Spring Boot Actuator: Production-ready features
• Spring Boot 2.2 Actuator Endpoints
• Building a RESTful Web Service with Spring Boot Actuator
• Spring Boot 2.0 Migration Guide / Spring Boot Actuator
• Spring Boot Actuator (June 8, 2018)
• Spring Boot Actuator: A Complete Guide (Feb. 27, 17)
  • Securing Actuator Endpoints

Endpoint	Description	Remarks
beans	Displays a complete list of all the Spring beans in your application.
env	Exposes properties from Spring’s ConfigurableEnvironment.

• Spring boot Security Disable security (May 27 '14)
  • spring.autoconfigure.exclude
  • security.basic.enabled, management.security.enabled : Deprecated in Spring Boot 2

• Pretty print JSON output of Spring Boot Actuator endpoints (Jul 1 '14)
  • spring.jackson.serialization.INDENT_OUTPUT: true

Error Control

• Error Handling

Class	Package	Description	Remarks
BasicErrorController (source)	o.s.b.autoconfigure.web
AbstractErrorController (source)	o.s.b.autoconfigure.web
DefaultErrorAttributes (source)	o.s.b.autoconfigure.web

Logging

• How to log SQL statements in Spring Boot?
  • logging.level.org.hibernate.SQL=DEBUG
  • logging.level.org.hibernate.type.descriptor.sql.BasicBinder=TRACE
  • logging.level.org.hibernate.type=TRACE
  • spring.jpa.properties.hibernate.show_sql=true
  • spring.jpa.properties.hibernate.format_sql=true
  • spring.jpa.properties.hibernate.use_sql_comments=true

REST

• Customize the Jackson ObjectMapper
• Spring From the Trenches: Parsing Date and Time Information From a Request Parameter (September 28, 2015)
• Configuring a global date & time format
• Parsing of LocalDate query parameters in Spring Boot (08/07/17)
• Set default format for LocalDateTime (jsr310) in spring when passed to a rest end point (Aug 27 '17)

• Spring Boot controller - Upload Multipart and JSON to DTO (Apr 15 '18)
  • @RequestPart("user") @Valid User user, @RequestPart("file") @Valid @NotNull @NotBlank MultipartFile file
• Uploading Files :
  • @RequestParam("file") MultipartFile file

Database

• Database Initialization
  • using JPA, using Hibernate, using Basic SQL Scripts

Property	Type/Values	Description	Remarks
spring.datasource.initialization-mode	always, never
spring.datasource.continue-on-error
spring.sql.init.mode	always, never
spring.sql.init.continue-on-error
spring.jpa.generate-ddl	boolean	switches the feature on and off and is vendor independent
spring.jpa.hibernate.ddl-auto	none, validate, update, create, create-drop	a Hibernate feature that controls the behavior in a more fine-grained way
spring.jpa.defer-datasource-initialization	boolean

• Configuring Hikari Connection Pool with Spring Boot (December 28, 2022)
• HikariCP properties

Property	Type/Values	Default	Description	Remarks
spring.datasource.hikari.connection-timeout	integer	2,000	maximum number of milliseconds that a client will wait for a connection
spring.datasource.hikari.minimum-idle	integer	10	minimum number of idle connections maintained by HikariCP in a connection pool
spring.datasource.hikari.maximum-pool-size	integer	10	maximum pool size
spring.datasource.hikari.idle-timeout	integer		maximum idle time for connection
spring.datasource.hikari.max-lifetime	integer		maximum lifetime in milliseconds of a connection in the pool after it is closed.
spring.datasource.hikari.auto-commit	boolean	true	default auto-commit behavior

Test

Spring Test

Class/Package	Description	Remarks
@ContextConfiguration	Defines class-level metadata that is used to determine how to load and configure an ApplicationContext for integration tests.
MockMvc	Main entry point for server-side Spring MVC test support.
SpringExtension	integrates the Spring TestContext Framework into JUnit 5's Jupiter programming model.
@SpringJUnitConfig	A composed annotation that combines @ExtendWith(SpringExtension.class) from JUnit Jupiter with @ContextConfiguration from the Spring TestContext Framework.

• Context Configuration with Annotated Classes
  • If you omit the classes attribute from the @ContextConfiguration annotation, the TestContext framework tries to detect the presence of default configuration classes. Specifically, AnnotationConfigContextLoader and AnnotationConfigWebContextLoader detect all static nested classes of the test class that meet the requirements for configuration class implementations, as specified in the @Configuration javadoc.
• Spring 3.1 M2: Testing with @Configuration Classes and Profiles (JUNE 21, 2011)
• How to Test the @Scheduled Annotation (February 21, 2019)
• Disable Test with Spring and Junit5 without context creation (Oct 9 '17)
• Spring @PropertySource using YAML (Jan 21 '14)

Spring Boot Test

Class/Package	Description	Remarks
@SpringBootTest	Annotation that can be specified on a test class that runs Spring Boot based tests.
enum SpringBootTest.WebEnvironment	An enumeration web environment modes	DEFINED_PORT, MOCK, NONE, RANDOM_PORT
@TestConfiguration	@Configuration that can be used to define additional beans or customizations for a test.	@TestConfiguration
@MockBean	Annotation that can be used to add mocks to a Spring ApplicationContext.
@WebMvcTest	Using this annotation will disable full auto-configuration and instead apply only configuration relevant to MVC tests (@Controller but not @Component, @Service or @Repository	@AutoConfigureWebMvc, @AutoConfigureMockMvc
@AutoConfigureMockMvc	Annotation that can be applied to a test class to enable and configure auto-configuration of MockMvc.
@DataJpaTest	Annotation for a JPA test that focuses only on JPA components.	@AutoConfigureTestDatabase
@AutoConfigureTestDatabase	Annotation that can be applied to a test class to configure a test database to use instead of any application defined or auto-configured data source.	AutoConfigureTestDatabase.Replace

• Spring Boot Test Tutorials

• Testing improvements in Spring Boot 1.4 (APRIL 15, 2016)
• Test that startup an Spring-boot application (Apr 7 '17)
  • webEnvironment
• Spring Boot and JUnit 5 (APRIL 12, 2017)
• Auto-configured Spring MVC Tests
  • @WebMvcTest auto-configures the Spring MVC infrastructure and limits scanned beans to @Controller, @ControllerAdvice, @JsonComponent, Converter, GenericConverter, Filter, WebMvcConfigurer, and HandlerMethodArgumentResolver. Regular @Component beans are not scanned when using this annotation.

• Spring Boot 1.4 @DataJpaTest - Error creating bean with name 'dataSource' (Dec 24 '16)
  • @DataJpaTest @AutoConfigureTestDatabase(replace = NONE)

• Auto configuration not necessary for unit testing

@EnableAutoConfiguration(exclude = {
    EndpointAutoConfiguration.class,    //o.s.b.actuate.autoconfigure.endpoint.EndpointAutoConfiguration
    JmxEndpointAutoConfiguration.class,
    InfoContributorAutoConfiguration.class,
    CompositeMeterRegistryAutoConfiguration.class,
    JvmMetricsAutoConfiguration.class,
    LogbackMetricsAutoConfiguration.class,
    MetricsAutoConfiguration.class,
    SystemMetricsAutoConfiguration.class,
    SimpleMetricsExportAutoConfiguration.class,
    HttpClientMetricsAutoConfiguration.class,
    MappingsEndpointAutoConfiguration.class,
    ManagementContextAutoConfiguration.class,
    ConditionsReportEndpointAutoConfiguration.class,
    DataSourceAutoConfiguration.class,
    DataSourceTransactionManagerAutoConfiguration.class,
    HibernateJpaAutoConfiguration.class,
    SecurityAutoConfiguration.class,
    OAuth2ClientAutoConfiguration.class,
    ReactiveOAuth2ClientAutoConfiguration.class,
    OAuth2ResourceServerAutoConfiguration.class,
    ReactiveOAuth2ResourceServerAutoConfiguration.class,
    FeignAutoConfiguration.class,
    TraceWebClientAutoConfiguration.class
})

Test Class Templates

Test class explicitly optimized

When testing service or repository classes, to execute the test more quickly, it is desirable not to load unnecessary beans such as MVC beans or actuator configuration beans. The following code sample shows how to do it.

@SpringBootTest(
    properties = { "management.endpoints.enabled-by-default=false" },
    webEnvironment=WebEnvironment.MOCK                   // NONE, MOCK, ...
)
@EnableAutoConfiguration(exclude = {
    EndpointAutoConfiguration.class,                      //o.s.b.actuate.autoconfigure.endpoint.EndpointAutoConfiguration
    WebEndpointAutoConfiguration.class,
    JmxEndpointAutoConfiguration.class,                   //o.s.b.actuate.autoconfigure.endpoint.jmx.JmxEndpointAutoConfiguration
    MappingsEndpointAutoConfiguration.class,              //o.s.b.actuate.autoconfigure.web.mappings.MappingsEndpointAutoConfiguration
    CompositeMeterRegistryAutoConfiguration.class,        //o.s.b.actuate.autoconfigure.metrics.CompositeMeterRegistryAutoConfiguration
    MetricsAutoConfiguration.class,                       //o.s.b.actuate.autoconfigure.metrics.MetricsAutoConfiguration
    JvmMetricsAutoConfiguration.class,                    //o.s.b.actuate.autoconfigure.metrics.JvmMetricsAutoConfiguration
    SystemMetricsAutoConfiguration.class,                 //o.s.b.actuate.autoconfigure.metrics.SystemMetricsAutoConfiguration
    LogbackMetricsAutoConfiguration.class,                //o.s.b.actuate.autoconfigure.metrics.LogbackMetricsAutoConfiguration
    HttpClientMetricsAutoConfiguration.class,             //o.s.b.actuate.autoconfigure.metrics.web.client.HttpClientMetricsAutoConfiguration
    SimpleMetricsExportAutoConfiguration.class,           //o.s.b.actuate.autoconfigure.metrics.export.simple.SimpleMetricsExportAutoConfiguration
    ManagementContextAutoConfiguration.class,             //o.s.b.actuate.autoconfigure.web.server.ManagementContextAutoConfiguration
    ServletManagementContextAutoConfiguration.class,
    ConditionsReportEndpointAutoConfiguration.class,      //o.s.b.actuate.autoconfigure.condition.ConditionsReportEndpointAutoConfiguration
    InfoContributorAutoConfiguration.class,               //o.s.b.actuate.autoconfigure.info.InfoContributorAutoConfiguration
    HealthContributorAutoConfiguration.class,
    DiskSpaceHealthContributorAutoConfiguration.class,
    DataSourceAutoConfiguration.class,                    //o.s.b.autoconfigure.jdbc.DataSourceAutoConfiguration
    DataSourceTransactionManagerAutoConfiguration.class,  //o.s.b.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration
    HibernateJpaAutoConfiguration.class,                  //o.s.b.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration
    SecurityAutoConfiguration.class,                      //o.s.b.autoconfigure.security.servlet.SecurityAutoConfiguration
    OAuth2ClientAutoConfiguration.class,                  //o.s.b.autoconfigure.security.oauth2.client.servlet.OAuth2ClientAutoConfiguration
    ReactiveOAuth2ClientAutoConfiguration.class,          //o.s.b.autoconfigure.security.oauth2.client.reactive.ReactiveOAuth2ClientAutoConfiguration
    OAuth2ResourceServerAutoConfiguration.class,          //o.s.b.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration
    ReactiveOAuth2ResourceServerAutoConfiguration.class,  //o.s.b.autoconfigure.security.oauth2.resource.reactive.ReactiveOAuth2ResourceServerAutoConfiguration
    FeignAutoConfiguration.class,                         //o.s.cloud.openfeign.FeignAutoConfiguration
    TraceWebClientAutoConfiguration.class                 //o.s.cloud.sleuth.instrument.web.client.TraceWebClientAutoConfiguration
})
@TestInstance(Lifecycle.PER_CLASS)
public class ApplicationInOptimalTest{

  private Logger logger = LoggerFactory.getLogger(this.getClass());

  // Define additional beans or customizations for a test.
  // Automatically loaded by @SpringBootTest without 'classes' property
  @TestConfiguration
  static class ExtraConfig{
      
    @Bean
    public CatalogService testCatalogService(){
       ...
    }
  }

  @Autowired
  private ApplicationContext springContext;

  @Autowired
  private OrderService orderService;

  @Autowired
  private CatalogService catalogService;

  @Test
  public void testGetBeanDefinitionNames() {

    final int cnt = springContext.getBeanDefinitionCount();
    final String[] names = springContext.getBeanDefinitionNames();
    Arrays.sort(names);

    this.logger.info("Defined Beans : {}", cnt);
    for(String name: names) this.logger.info("  - {}", name);

    Assertions.assertTrue(cnt > 0, "The Spring container has no bean which makes no sense.");
    Assertions.assertTrue(Arrays.binarySearch(names, "web3j") > -1, "The Spring container doesn't contain 'web3j' bean, which is never expected.");
    Assertions.assertTrue(Arrays.binarySearch(names, "mvcViewResolver") < 0, "The Spring container still contains 'mvcViewResolver' bean, which is not expected.");
  }

  @Test
  public void testGetConfigurations() {

    final Map<String, Object> configs = springContext.getBeansWithAnnotation(Configuration.class);
    final int cnt = configs.size();

    this.logger.info("Configurations : {}", cnt);
    configs.forEach((k, v) -> this.logger.info("   - {} : {}", k, v));

    Assertions.assertTrue(cnt > 0, "The Spring container has no configuration, which is impossible.");
  }
}

Test class for literally unit test

It is possible to auto-wire test-purpose bean instead of a bean in normal(non-test) Spring Boot configuration (like EthereumClientConfig in below example) by defining @Primary bean in the extra configuration imported only by test.

@SpringBootTest(
    classes = {IdentityManagerContractServiceImpl.class, EthereumClientConfig.class},
    properties = {"management.endpoints.enabled-by-default=false", "security=", "spring.security.enabled=false"},
    webEnvironment = WebEnvironment.NONE)
@TestInstance(Lifecycle.PER_CLASS)
@Import(IdentityManagerContractServiceImplTest.ExtraConfig.class)
class IdentityManagerContractServiceImplTest{

  final private Logger logger = LoggerFactory.getLogger(this.getClass());

  // Define additional beans or customizations for a test.
  // NOT loaded automatically by @SpringBootTest with 'classes' property
  // Use '@Import' to load explicitly
  @TestConfiguration
  static class ExtraConfig{
     ...

     // Make another bean instead of a bean in normal configuration to be autowired using @Primary annotation.
     @Bean @Primary
     SendTxProcessor sendTxProcessorWithoutRetry(){
        ...
     }
  }

  @SpyBean
  private TestSpecialAccountServiceImpl specialAccountSrv;

  @Autowired
  private IdentityManagerContractService identityManagerContract;

  ...

}

Test class for concurrency behavior

To test a method in concurrent executions, apply parallel execution(@Execution(CONCURRENT)) and repeated test(@RepeatedTest) together. The life-cycle of the test instance is expected to be PER_METHOD.

@SpringBootTest(
    classes = {SafeTokenContractServiceImpl.class, EthereumClientConfig.class},
    properties = {"management.endpoints.enabled-by-default=false", "security=", "spring.security.enabled=false"},
    webEnvironment = WebEnvironment.NONE)
@Import(SafeTokenContractServiceImplConcurrentTest.ExtraConfig.class)
@TestInstance(Lifecycle.PER_METHOD)
@Execution(ExecutionMode.CONCURRENT)
public class SafeTokenContractServiceImplConcurrentTest{

  final private Logger logger  = LoggerFactory.getLogger(this.getClass());

  @TestConfiguration
  static class ExtraConfig{

    @Bean
    public AccountService testAccountService() throws Exception {
      ...
    }

    ...
  }

  @Value("${smart-contracts.safe-token.address}")
  private String tokenAddress;

  @Autowired
  private AccountService accountSrv;

  @Autowired
  private SafeTokenContractServiceImpl tokenContractSrv;

  @RepeatedTest(10)
  @Execution(ExecutionMode.CONCURRENT)
  public void testMint() {
    ...
    try {
      this.tokenContractSrv.mint(from, to, amt);
    }catch(Exception ex) {
      this.logger.error("Fail to execute `mint`", ex);
      throw ex;
    }
  }

For the above test case to run correctly not affecting other test cases that has no @EXECUTION(CONCURRENT), following is proper for JUnit Platform configuration file(junit-platform.properties).

! https://junit.org/junit5/docs/current/user-guide/#running-tests-config-params
! https://junit.org/junit5/docs/current/user-guide/#writing-tests-parallel-execution

junit.jupiter.testinstance.lifecycle.default = per_class
junit.jupiter.execution.parallel.enabled = true
# junit.jupiter.execution.parallel.mode.default = concurrent
# junit.jupiter.execution.parallel.mode.classes.default = concurrent

Test class for only JPA repositories

@DataJpaTest
@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
@TestInstance(Lifecycle.PER_CLASS)
class SpecialAccountRepositoryTest{

  final private Logger logger = LoggerFactory.getLogger(this.getClass());

  @Autowired
  private SpecialAccountRepository specialAccountRepos;

  ...

}

misc

• Configuring Logback With Spring Boot (Sep. 03, 17)
• USING YAML IN SPRING BOOT TO CONFIGURE LOGBACK (May 5, 2016)
• How do I set the Hibernate dialect in SpringBoot? (Jul 26 '16)
  • spring.jpa.properties.hibernate.dialect
  • spring.jpa.database-platform
• Spring Boot - How to log all requests and responses with exceptions in single place? (Apr 26 '17)
  • CommonsRequestLoggingFilter

Spring Security

• http://projects.spring.io/spring-security/
• Desc. : a powerful and highly customizable authentication and access-control framework.
• Sources : https://github.com/spring-projects/spring-security
• Maven artifacts

References

Spring Security 5.1

• Spring Security 5.1 Reference
• Spring Security 5.1 API
• Spring Security 5.1 Guides

Spring Security 4.2.2

• Spring Security 4.2.2 Reference
  • Spring MVC Integration
• Spring Security 4.2.2 API

Spring Security 3.1

• Spring Security 3.1.x Reference Manual
• Spring Security 3.1.x API

• org/springframework/security/messages.properties

Concepts

• Access control in computer security
• ACL(Access Control List)
• JAAS(Java Authentication and Authorization Service)
• Spring Security Core Components : SecurityContext, Authentication, GrantedAuthority, UserDetails, UserDetailsService

Concept	Description	API	Remarks
Principal	the abstract notion of a principal, which can be used to represent any entity, such as an individual, a corporation, and a login id	java.security.Principal	Party
Subject	a grouping of related information for a single entity, such as a person, including the Subject's identities as well as its security-related attributes (passwords and cryptographic keys, for example)	javax.security.auth.Subject	A subject can contain multiple principals and a principal represents the face of a subject.
Authentication	authenticated principal	o.s.security.core.Authentication	interface Authentication extends Principal
GrantedAuthority	application-wide permissions granted to a principal	o.s.security.core.GrantedAuthority	Role

API

Class	Source	Description	Remarks
Authentication
UsernamePasswordAuthenticationToken		An Authentication implementation that is designed for simple presentation of a username and password
TestingAuthenticationToken		An Authentication implementation that is designed for use whilst unit testing

General

• Spring Boot Security Application (25/12/2014)

Session Management

• Control the Session with Spring Security(March 10, 2017)

• How to get active user's UserDetails (Jan 6 '12)
• @AuthenticationPrincipal

Authentication

Authorization

• Expression-Based Access Control in Spring Security 4.2
• Expression-Based Access Control in Spring Security 3.1

Spring Session

• http://projects.spring.io/spring-session/
• Desc. : provides an API and implementations for managing a user’s session information

References

Spring Session 1.3.0

• Spring Session 1.3.0 Reference
• Spring Session 1.3.0 API

Spring Integration

• Spring Integration Documentations

• Spring Integration 5.2 API

Spring Data

• Projects

Project	Description	Documentation	API	Remarks
Spring Data Commons	part of the umbrella Spring Data project that provides shared infrastructure across the Spring Data projects and contains technology neutral repository interfaces as well as a metadata model for persisting Java classes.	Spring Data Commons Reference

• Common Annotations

Annotation	Description	Remarks
@Id	Demarcates an identifier.
@AccessType	Define how Spring Data shall access values of persistent properties.	Type.FIELD | TYPE.PROPERTY

Spring Data JPA

• Spring JpaRepository - Detach and Attach entity(Nov 7 '14)

• JPA Annotations
• javax.persistence package
  • @Entity, @Table, @Column, @Id, @IdClass, @Transient, @Temporal, @ForeignKey, @Index, @UniqueConstraint, @OneToOne, @OneToMany, @ManyToOne, @ManyToMany, @JoinColumn, @JoinTable, @Inheritance, @DiscriminatorColumn, @DiscriminatorValue

Annotation	Description	Remarks
@Entity	Specifies that the class is an entity
@Table	Specifies the primary table for the annotated entity	name, catalog
@Column	Specifies the mapped column for a persistent property or field	name, columnDefinition, nullable, unique, length, precision, scale
@Id	Specifies the primary key of an entity
@IdClass	Specifies a composite primary key class that is mapped to multiple fields or properties of the entity
@Transient	Specifies that the property or field is not persistent
@Temporal	Specified for persistent fields or properties of type java.util.Date and java.util.Calendar
@ForeignKey	Used to specify the handling of foreign key constraints when schema generation is in effect
@Index	Used in schema generation to specify creation of an index
@UniqueConstraint	Specifies that a unique constraint is to be included in the generated DDL for a primary or secondary table

Spring Data MongoDB

• Spring Data MongoDB 3.2 Reference
• Spring Data MongoDB 3.2 API

• Mapping

• MongoDB Driver Quick Start
• Accessing Data with MongoDB

Core Classes

Class	Description	Source	Remarks
AbstractMongoClientConfiguration	Base class for Spring Data MongoDB configuration using JavaConfig with MongoClient.	AbstractMongoClientConfiguration.java@3.1.3
MongoJsonSchemaCreator	Extracts the MongoJsonSchema for a given Class by applying the following mapping rules.		factory method

Annotation	Description	Source	Remarks
@Document	Identifies a domain object to be persisted to MongoDB.
@Field	Annotation to define custom metadata for document fields.
@Indexed	Mark a field to be indexed using MongoDB's indexing feature.

Readings

• Spring Data MongoDB Property Population
  1. If the property is immutable but exposes a with… method, we use the with… method to create a new entity instance with the new property value.
  2. If property access (i.e. access through getters and setters) is defined, we’re invoking the setter method.
  3. If the property is mutable we set the field directly.
  4. If the property is immutable we’re using the constructor to be used by persistence operation to create a copy of the instance.
  • By default, we set the field value directly.

• Generating document schema from domain object
  • org.springframework.data.mongodb.core.MongoJsonSchemaCreator

• Nullability Annotations

Typical Code Samples

Typical configuration bean

/**
 * @author 3rdstage
 *
 * @see <tt><a href='https://github.com/spring-projects/spring-data-mongodb/blob/3.1.3/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/AbstractMongoClientConfiguration.java'>AbstractMongoClientConfiguration.java</a></tt>
 */
@Configuration
@EnableMongoRepositories
public class MongoClientConfig extends AbstractMongoClientConfiguration{

  final private Logger logger = LoggerFactory.getLogger(this.getClass());

  @Bean
  @Override
  public MongoClient mongoClient() {
    return super.mongoClient();
  }

  @Override
  protected String getDatabaseName() {
    return "eth";
  }

  @Override
  protected String getMappingBasePackage() {
    return "thirdstage.eth.disassembly.repos";
  }

  @Override
  public boolean autoIndexCreation() {
    return true;
  }

  // https://docs.spring.io/spring-data/mongodb/docs/3.2.x/reference/html/#mongo.custom-converters.xml
  @Override
  protected void configureConverters(MongoConverterConfigurationAdapter adapter) {
    super.configureConverters(adapter);
    //adapter.registerConverter(new EpochTimeToDateConverter());
    //adapter.registerConverter(new EpochTimeFromDateConverter());
  }

  @Bean
  public MongoClientSettingsBuilderCustomizer customizer() {
    return (builder) -> {
      List<Convention> cvns = Conventions.DEFAULT_CONVENTIONS;
      //cvns.add(Conventions.SET_PRIVATE_FIELDS_CONVENTION);
      CodecRegistry pojoCodecRegistry = CodecRegistries.fromRegistries(
        MongoClientSettings.getDefaultCodecRegistry(),
        CodecRegistries.fromProviders(
            PojoCodecProvider.builder()
              .automatic(true)
              .conventions(cvns)
              .build()));
      builder.codecRegistry(pojoCodecRegistry);
    };
  }
}

Domain Object with custom type conversion using converted typed getter/setter without global type converter

@Getter
@Setter
@RequiredArgsConstructor
@Accessors(chain = true)
@Document(collection = "transactions")
public class Transaction implements java.io.Serializable{

  @Id
  private final String hash;

  @Field(name = "block_no")
  private long blockNo;

  private long index;

  private String from;

  // denormalized field from account
  @Field("from_is_contr")
  private boolean fromIsContract;

  private String to;

  // denormalized field from account
  @Field("to_is_contr")
  private boolean toIsContract;

  @Getter(AccessLevel.NONE)
  @Setter(AccessLevel.NONE)
  @AccessType(AccessType.Type.FIELD)
  @Field(targetType = DECIMAL128)
  private BigDecimal value;

  public BigInteger getValue() {
    return this.value.toBigInteger();
  }

  public Transaction setValue(BigInteger val) {
    this.value = new BigDecimal(val);
    return this;
  }

  @Indexed
  private Instant at;

}

Spring Data Redis

• Spring Data Redis 2.2 Reference
• Spring Data Redis 2.2 API

Spring Cloud

• Building Microservices with Spring Cloud and Docker (July 12, 2015)

Spring Cloud OpenFeign

• https://spring.io/projects/spring-cloud-openfeign
• Desc. : provides OpenFeign integrations for Spring Boot apps through autoconfiguration and binding to the Spring Environment and other Spring programming model idioms.
• Sources :
• Maven artifacts : org.springframework.cloud » spring-cloud-starter-openfeign

Version	Documentation	API	Remarks
3.1	Spring Cloud OpenFeign 3.1.0 Reference	Spring Cloud OpenFeign Core 3.1.0 API

misc

XML Schemas

Name	Namespace	Description	Sources
beans	http://www.springframework.org/schema/beans	Defines the elements to define beans.	spring-beans-4.0.xsd
context	http://www.springframework.org/schema/context	Defines the configuration elements for the Spring Framework's application.	org.springframework.context.config spring-context-4.0.xsd
aop	http://www.springframework.org/schema/aop	Defines the configuration elements for the Spring Framework's AOP support.	org.springframework.aop.config spring-aop-4.0.xsd
jdbc	http://www.springframework.org/schema/jdbc	Defines the configuration elements for the Spring Framework's embedded database support.	org.springframework.jdbc.config spring-jdbc-4.0.xsd
tx	http://www.springframework.org/schema/tx	Defines the elements used in the Spring Framework's declarative transaction management infrastructure.	spring-tx-3.0.xsd
mvc	http://www.springframework.org/schema/mvc		spring-mvc-3.0.xsd
util	http://www.springframework.org/schema/util		spring-util-4.0.xsd
task	http://www.springframework.org/schema/task/		spring-task-4.2.xsd

Projects

Spring Retry

• https://github.com/spring-projects/spring-retry Spring Retry]
• Desc. : provides declarative retry support for Spring applications.

Samples

Common Spring Boot Application Configuration

# https://docs.spring.io/spring-boot/docs/2.2.x/reference/html/appendix-application-properties.html

debug: !!bool ${SPRING_DEBUG:false}
trace: !!bool ${SPRING_TRACE:false}

logging.level:
  org.springframework: INFO
  org.springframework.boot.autoconfigure: WARN
  org.apache.tomcat: INFO
  org.apache.catalina: INFO
  org.eclipse.jetty: INFO
  org.hibernate.SQL: WARN
  org.hibernate.type: WARN
  org.hibernate.tool.hbm2ddl: TRACE

server:
  port: 8080

jwt:
  secret: javainuse

spring:
  application.name: foo-bar
  profiles:
    active: local
  main.allow-bean-definition-overriding: false
  output:
    ansi:
      enabled: always  # https://docs.spring.io/spring-boot/docs/2.1.x/reference/html/boot-features-logging.html#boot-features-logging-color-coded-output
  servlet:
    multipart:
      max-file-size: 100MB
      max-request-size: 100MB

spring.aop:
  auto: true  # Add @EnableAspectJAutoProxy.
  proxy-target-class: true  # Whether subclass-based (CGLIB) proxies are to be created (true), as opposed to standard Java interface-based proxies (false).

spring.security:
  user:
    name: boot
    password: boot

springdoc:
  use-fqn: false
  swagger-ui:
    show-common-extensions: true
    default-model-rendering: "example"   # ("example" | "model")
    default-models-expand-depth: 5
    default-model-expand-depth: 5
    disable-swagger-default-url: false
    #validator-url: 'none'   # 'none' : no validation
  api-docs:
    path: /swagger-ui/api-docs
    enabled: true

---
spring.profiles: local

debug: !!bool ${SPRING_DEBUG:true}
trace: !!bool ${SPRING_TRACE:false}

logging.level:
  org.hibernate.SQL: DEBUG
  org.hibernate.type: TRACE
  # https://cloud.spring.io/spring-cloud-static/spring-cloud-openfeign/2.2.3.RELEASE/reference/html/#feign-logging

spring:
  autoconfigure:
    exclude[0]: org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration
    exclude[1]: org.springframework.boot.actuate.autoconfigure.security.servlet.ManagementWebSecurityAutoConfiguration
  jackson.serialization.INDENT_OUTPUT: true

spring.jpa:
  properties.hibernate:
    show_sql: true
    format_sql: true
    use_sql_comments: true

# https://docs.spring.io/spring-boot/docs/current/reference/html/production-ready-features.html#production-ready-endpoints-enabling-endpoints
management.endpoints:
  enabled-by-default: true
  shutdown.enabled: false
  web.exposure.include: "*"
  jmx.exposure.include: "*"
  jmx.exposure.exclude: 

resttemplate:
  base:
    url: http://localhost:8080

spring.data.mongodb:
  host: 127.0.0.1
  port: 27017
  username: ${MONGODB_USER}
  password: ${MONGODB_PASSWORD}
  authentication-database: ${MONGODB_AUTH_DATABASE}

Working of @Transactional annotation according to the processing mode(proxy or aspectj)

Test code outline

• Annotated method is private : private SearchRequest createAndPersistNewSearchReq()
• In-call is invoked from testProcess to createAndPersistNewSearchReq()

public class SearchTaskProcessorTest{

  //...
  ConfigurableApplicationContext spring;
  private SearchMasterMapper masterMapper;
  private SearchDetailMapper detailMapper;
  private SearchRoiMapper roiMapper;
  private SearchRoiParamMapper roiParamMapper;
  private SearchRoiPointMapper roiPointMapper;

  @BeforeClass
  public void beforeClass() throws Exception{

    //...
    this.spring = new ClassPathXmlApplicationContext(CONFIG_LOCATION);
    this.spring.registerShutdownHook();
    this.masterMapper = this.spring.getBean("searchMasterMapper", SearchMasterMapper.class);
    this.detailMapper = this.spring.getBean("searchDetailMapper", SearchDetailMapper.class);
    this.roiMapper = this.spring.getBean("searchRoiMapper", SearchRoiMapper.class);
    this.roiParamMapper = this.spring.getBean("searchRoiParamMapper", SearchRoiParamMapper.class);
    this.roiPointMapper = this.spring.getBean("searchRoiPointMapper", SearchRoiPointMapper.class);
  }

  @AfterClass
  public void afterClass(){ }

  @Transactional
  private SearchRequest createAndPersistNewSearchReq(){

    //...
    this.masterMapper.insertSearchMaster(req);
    this.detailMapper.insertSearchDetail(req.getId(), cctv);
    this.roiMapper.insertSearchRoi(req.getId(), cctv.getSystemId(), cctv.getId(), roi);

    for(Param param: roi.getParams()){
      this.roiParamMapper.insertSearchRoiParam(req.getId(), cctv.getSystemId(),
        cctv.getId(), roi.getNo(), param);
    }
    for(Point pt: roi.getPoints()){
      this.roiPointMapper.insertSearchRoiPoint(req.getId(), cctv.getSystemId(),
        cctv.getId(), roi.getNo(), pt);
    }

    return req;
  }

  @Test
  public void testProcess(){

    SearchRequest req = this.createAndPersistNewSearchReq();
    SearchTaskProcessor processor = this.spring.getBean(...);

    //...

    processor.process(req.getId(), "1", crtr);
  }
}

In proxy mode

• Log