java - Spring 自定义注解

Question

我不确定是否可以轻松地做我想做的事。我有以下 Controller ，它既可以用作休息 Controller ，也可以用作 websocket Controller :

@RestController
@RequestMapping("rest/user")
@MessageMapping("/user")
public class UserController {

    @Autowired
    private UserRepo userRepo;

    @RequestMapping("/list")
    @MessageMapping("/list")
    @SendTo("/channel/user")
    public apiResImpl list() {      
        Iterable<UserImpl> users = userRepo.findAll();  
        return users != null ? new apiResImpl("success", users) :  new apiResImpl("fail");
    }

 ...

我想将这些注释中的几个包装在两个自定义注释@ApiController 和@ApiMapping 中

像这样:

@ApiController("/user")
public class UserController {

    @Autowired
    private UserRepo userRepo;

     @ApiMapping("/list")
     public apiResImpl list() {     
         Iterable<UserImpl> users = userRepo.findAll(); 
         return users != null ? new apiResImpl("success", users) :  new apiResImpl("fail");
     }

 ...

我遇到的问题是能够将值传递到内部传递给 spring 注释的自定义注释中。这个@interface 会是什么样子？有例子吗？

谢谢!

Answer 1

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Documented
@RequestMapping // meta-annotated RequestMapping 
@MessageMapping // meta-annotated MessageMapping
public @interface ApiController {

     @AliasFor(annotation = RequestMapping.class, attribute = "value") // -> alias for RequestMapping value attribute
     String[] value() default {};

     @AliasFor(annotation = MessageMapping.class, attribute = "value") // -> alias for MessageMapping value attribute
     String[] mvalue() default{};   
}


@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD})
@Documented
@RequestMapping
@MessageMapping
public @interface ApiMapping {

    @AliasFor(annotation = RequestMapping.class, attribute = "value")
    String[] value() default {};

    @AliasFor(annotation = MessageMapping.class, attribute = "value")
    String[] mvalue() default {};

    @AliasFor(annotation = RequestMapping.class, attribute = "method")
    RequestMethod[] method() default {};
}

引用下面的链接，我想出了这个解决方案，使用这种技术，我们可以为元注释注释的属性指定一个别名，即(这里是 RequestMapping、MessageMapping)。

AliasFor 的一个缺点是，它是不可重复的注解。

http://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/#_core_container_improvements_2