SpringBoot(三)_controller的使用

@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)