@RestController 
public class UserController { 
  private UserService userService; 
  @Autowired 
  public UserController(UserService userService) { 
    this.userService = userService; 
  } 
  @RequestMapping("/test") 
   public User view() { 
    User user = new User(); 
    user.setId(1L); 
    user.setName("haha"); 
    return user; 
  } 
  @RequestMapping("/test2") 
  public String view2() { 
    return "{\"id\" : 1}"; 
  } 
} 

@org.springframework.stereotype.Controller 
@org.springframework.web.bind.annotation.ResponseBod 
public @interface RestController { 
} 

<context:component-scan base-package="com.bjpowernode.spring4"/> 
<mvc:annotation-driven/>  

@RestController 
public class UserController { 
  private UserService userService; 
  @Autowired 
  public UserController(UserService userService) { 
    this.userService = userService; 
  } 
  @RequestMapping("/api") 
   public Callable<User> api() { 
    System.out.println("=====hello"); 
    return new Callable<User>() { 
      @Override 
      public User call() throws Exception { 
        Thread.sleep(10L * 1000); //暂停两秒 
        User user = new User(); 
        user.setId(1L); 
        user.setName("haha"); 
        return user; 
      } 
    }; 
  } 
} 

public static void main(String[] args) { 
  AsyncRestTemplate template = new AsyncRestTemplate(); 
  //调用完后立即返回（没有阻塞） 
  ListenableFuture<ResponseEntity<User>> future = template.getForEntity("http://localhost:9080/spring4/api", User.class); 
  //设置异步回调 
  future.addCallback(new ListenableFutureCallback<ResponseEntity<User>>() { 
    @Override 
    public void onSuccess(ResponseEntity<User> result) { 
      System.out.println("======client get result : " + result.getBody()); 
    } 
    @Override 
    public void onFailure(Throwable t) { 
      System.out.println("======client failure : " + t); 
    } 
  }); 
  System.out.println("==no wait"); 
} 

<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"/> 
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"> 

<mvc:annotation-driven/>  

<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping"/> 
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">