Spring Framework Series (seven) - Spring Common Annotations

Spring section:

1, the statement bean notes:

@Component: component, there is no clear role

@Service: Use (service layer) Yewuluojiceng

@Repository: Use (DAO layer) in the data access layer

@Controller: the presentation layer using statement Controller (Controller)

2, injected bean notes:

@Autowired: provided by Spring, according to the type of injection, if a plurality of interfaces implemented with the use needs and @Qualifier

@Inject: JSR-330 by

@Resource: by JSR-250, injected by name

Can comment on a set of methods and properties, it recommended annotation on the property.

3, java configuration or related notes:

@Bean comment on the method, declare the current method returns a value of a bean, if you use third-party tools, you need to use @Bean assembled, otherwise use xml form

@Configuration declare the current class to class configuration, which combines internal @Component comments, indicating that this class is a bean

Component for scanning @ComponentScan

@WishlyConfiguration combination with @ComponentScan @Configuration annotations can replace the two annotations

4, section (AOP) related notes:

Spring supports AspectJ annotation style section of programming.

@Aspect Declaring an aspect

Use @ After, @ Before, @ Around defined suggestions (advice), may be blocking rules (cutting point) as parameters directly.

@After performed after performing the method (the method)

@Before performed prior to performing the method (the method)

@Around performed before the method is performed after (the method)

@PointCut sound Mingqie point

Use @EnableAspectJAutoProxy in java class configuration support for AspectJ annotation open Spring agents (the class)

5, @ Bean's property support:

How to create a new container is provided @Scope Spring Bean instance (the method, must have @Bean)

Provided types include:

Singleton (single embodiment, a container only a bean instance, the Spring default mode),

Protetype (each call to create a new bean),

Request (web project, every http request to create a new bean),

Session (web projects, each http session to create a new bean),

GlobalSession (to each create a new global http session Bean instance)

@StepScope also involved in the Spring Batch

@PostConstruct by JSR-250, executed after executing the constructor, equivalent to the xml configuration file in the bean initMethod

@PreDestory by JSR-250, before performing the destruction Bean, equivalent to the bean xml configuration file destroyMethod

6, @ Value Note: to inject property value

Support of the injection follows:

1) injected ordinary characters

@Value("Michael")

String name;

2) operating system properties injection

@Value("#{systemProperties['os.name']}")

String osName;

3) injected expression results

@Value("#{ T(java.lang.Math).random() * 100}")

String randomNumber;

4). Other injection bean properties

@Value("#{ domeClass.name}")

String name;

5).注入文件资源

@Value("classpath:com/it/test.txt")

String Resource file;

6).注入网站资源

@Value("http://www.baidu.com")

Resource url;

7).注入配置文件

@Value("${book.name} ")

String bookName;

注入配置使用方法:

① 编写配置文件(test.properties)

book.name=《三体》

② @PropertySource 加载配置文件(类上)

@PropertySource("classpath:com/it/test.properties")

③ 还需配置一个PropertySourcesPlaceholderConfigurer的bean。

7、环境切换

@Profile 通过设定Environment的ActiveProfiles来设定当前context需要使用的配置环境。(类或方法上)

@Conditional Spring4中可以使用此注解定义条件话的bean,通过实现Condition接口,并重写matches方法,从而决定该bean是否被实例化。

8、异步相关

@EnableAsync 配置类中,通过此注解开启对异步任务的支持,叙事性AsyncConfigurer接口(类上)

@Async 在实际执行的bean方法使用该注解来申明其是一个异步任务(方法上或类上所有的方法都将异步,需要@EnableAsync开启异步任务)

9、定时任务相关

@EnableScheduling 在配置类上使用,开启计划任务的支持(类上)

@Scheduled 来申明这是一个任务,包括cron,fixDelay,fixRate等类型(方法上,需先开启计划任务的支持)

10、@Enable*注解说明

这些注解主要用来开启对xxx的支持。

@EnableAspectJAutoProxy 开启对AspectJ自动代理的支持

@EnableAsync 开启异步方法的支持

@EnableScheduling 开启计划任务的支持

@EnableWebMvc 开启Web MVC的配置支持

@EnableConfigurationProperties 开启对@ConfigurationProperties注解配置Bean的支持

@EnableJpaRepositories 开启对SpringData JPA Repository的支持

@EnableTransactionManagement 开启注解式事务的支持

@EnableTransactionManagement 开启注解式事务的支持

@EnableCaching 开启注解式的缓存支持

11、测试相关注解

@RunWith 运行器,Spring中通常用于对JUnit的支持

@RunWith(SpringJUnit4ClassRunner.class)

@ContextConfiguration 用来加载配置ApplicationContext,其中classes属性用来加载配置类

@ContextConfiguration(classes={TestConfig.class})

Spring部分:

@EnableWebMvc 在配置类中开启Web MVC的配置支持,如一些ViewResolver或者MessageConverter等,若无此句,重写WebMvcConfigurerAdapter

方法(用于对SpringMVC的配置)。

@Controller 声明该类为SpringMVC中的Controller

@RequestMapping 用于映射Web请求,包括访问路径和参数(类或方法上)

@ResponseBody 支持将返回值放在response内,而不是一个页面,通常用户返回json数据(返回值旁或方法上)

@RequestBody 允许request的参数在request体中,而不是在直接连接在地址后面。(放在参数前)

@PathVariable 用于接收路径参数,比如@RequestMapping(“/hello/{name}”)申明的路径,将注解放在参数中前,即可获取该值,通常作为

Restful的接口实现方法。

@RestController 该注解为一个组合注解,相当于@Controller和@ResponseBody的组合,注解在类上,意味着,该Controller的所有方法都默认

加上了@ResponseBody。

@ControllerAdvice 通过该注解,我们可以将对于控制器的全局配置放置在同一个位置,注解了@Controller的类的方法可使用@ExceptionHandler

、@InitBinder、@ModelAttribute注解到方法上,

这对所有注解了 @RequestMapping的控制器内的方法有效。

@ExceptionHandler 用于全局处理控制器里的异常

@InitBinder 用来设置WebDataBinder,WebDataBinder用来自动绑定前台请求参数到Model中。

@ModelAttribute 本来的作用是绑定键值对到Model里,在@ControllerAdvice中是让全局的@RequestMapping都能获得在此处设置的键值对。

 

总结:上面几乎都是常用的Spring相关注解,而且大部分内容,在前面Spring相关博客也都有讲过,这里转载别人的总结,方便记忆,只不过具体的

解释不够详细,可以查看我之前的内容,或者自行百度

原文链接:https://blog.csdn.net/yelvgou9995/article/details/83345267

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Origin www.cnblogs.com/huigelaile/p/10990583.html