针对controller 中 如何使用注解进行解析

@RestController

• 返回数据类型为 Json 字符串，特别适合我们给其他系统提供接口时使用。

@RequestMapping

(1) 不同前缀访问同一个方法,此时访问hello和hi 都可以访问到say（）这个方法

    @RequestMapping(value = {"/hello","/hi"},method = RequestMethod.GET)
    public String say(){
        return girlProperties.getName();
    }

（2）给类一个RequestMapping, 访问时就是：http://localhost:8099/hello/say

@RestController
@RequestMapping("/hello")
public class HelloController {

    @Resource
    private  GirlProperties girlProperties;
    @RequestMapping(value = "/say",method = RequestMethod.GET)
    public String say(){
        return girlProperties.getName();
    }
}

@PathVariable：获取url中的数据

@RestController
@RequestMapping("/hello")
public class HelloController {

    @Resource
    private  GirlProperties girlProperties;
    @RequestMapping(value = "/say/{id}",method = RequestMethod.GET)
    public String say(@PathVariable("id") Integer id){
        return "id :"+id;
    }
}

访问http://localhost:8099/hello/say/100, 结果如下

id :100

@RequestParam :获取请求参数的值

(1) 正常请求

@RestController
@RequestMapping("/hello")
public class HelloController {

    @Resource
    private  GirlProperties girlProperties;
    @RequestMapping(value = "/say",method = RequestMethod.GET)
    public String say(@RequestParam("id") Integer id){
        return "id :"+id;
    }
}

访问 http://localhost:8099/hello/say?id=111 结果如下

id :111

（2）设置参数非必须的，并且设置上默认值

@RestController
@RequestMapping("/hello")
public class HelloController {

    @Resource
    private  GirlProperties girlProperties;
    @RequestMapping(value = "/say",method = RequestMethod.GET)
    public String say(@RequestParam(value = "id",required = false,defaultValue = "0") Integer id){
        return "id :"+id;
    }
}

访问http://localhost:8099/hello/say 结果如下

id :0

@GetMapping ，当然也有对应的Post等请求的简化写法

• 这里对应的就是下面这句代码

  @GetMapping("/say")
  //等同于下面代码
  @RequestMapping(value = "/say",method = RequestMethod.GET)