1.简单参数接收

前端请求参数与Controller接受变量名一致

如果参数名不一致，接受不成功。
可以用@RequestParam指定参数名，可以用username接收（不推荐）。
required = true，表示参数必须传递，如果不传递会报错,false代表可选的参数，可以不传递

    @RequestMapping("/simplePara")public String simplePara(@RequestParam(name="name",required = false) String username, Integer age){System.out.println(username+":"+age);return "OK";}

## 2.实体参数接收

请求参数名与形参对象属性名相同

    @RequestMapping("/simplePojo")public String simplePojo(User user){System.out.println(user);return "OK";}

3.复杂实体参数接收

    @RequestMapping("/complexPojo")public String complexPojo(User user){System.out.println(user);return "OK";}

4.数组参数接收

    @RequestMapping("/arrayPara")public String arrayPara(String[] hobby){System.out.println(Arrays.toString(hobby));return "OK";}

5.集合接收

• 请求参数名hobby与 集合变量名相同hobby
• 加上@RequestParam
  ```java
  @RequestMapping(“/listPara”)
  public String listPara(@RequestParam List hobby){
  System.out.println(hobby);
  return “OK”;
  }
  ``

6.日期参数接收

• 后端要使用@DateTimeFormat注解标记参数
• 后端接收要指定接收日期的格式（与前端传递的格式一样）：yyyy-MM-dd HH:mm:ss
  

    @RequestMapping("/dataParam")public String dataParam(@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") LocalDateTime updateTime){System.out.println(updateTime);return "OK";}

7.Json格式参数接收

• 后端通过实体对象接收数据
• 请求参数需要用@RequestBody 标记

   @RequestMapping("/jsonParam")public String jsonParam(@RequestBody User user){System.out.println(user);return "OK";}

8.路径参数，参数已经是url的一部分\

• {id}是个路径参数
• 参数需要用@PathVariable 标记

    @RequestMapping("/pathParam/{id}")public String pathParam(@PathVariable Integer id){System.out.println(id);return "OK";}//多个路径参数@RequestMapping("/pathParam2/{id}/{name}")public String pathParam(@PathVariable Integer id,@PathVariable String name){System.out.println(id + ":" + name);return "OK";}

总结

常用注解

每个接口返回的数据有各种类型(字符串,数组,Json)，不规范

可以用Result封装返回的数据

• 响应字符串请求
  

• 响应json请求
  

• 响应集合请求

• 

public class Result {private Integer code ;//1 成功 , 0 失败private String msg; //提示信息private Object data; //数据 datapublic Result() {}public Result(Integer code, String msg, Object data) {this.code = code;this.msg = msg;this.data = data;}public Integer getCode() {return code;}public void setCode(Integer code) {this.code = code;}public String getMsg() {return msg;}public void setMsg(String msg) {this.msg = msg;}public Object getData() {return data;}public void setData(Object data) {this.data = data;}public static Result success(Object data){return new Result(1, "success", data);}public static Result success(){return new Result(1, "success", null);}public static Result error(String msg){return new Result(0, msg, null);}@Overridepublic String toString() {return "Result{" +"code=" + code +", msg='" + msg + '\'' +", data=" + data +'}';}
}

请求处理代码

@RestController
public class ResponseController {//统一相应结果@RequestMapping("/hello")public Result hello(){System.out.println("Hello World ~");//return new Result(1,"success","Hello World ~");return Result.success("Hello World ~");}@RequestMapping("/getAddr")public Result getAddr(){Address addr = new Address();addr.setProvince("广东");addr.setCity("深圳");return Result.success(addr);}@RequestMapping("/listAddr")public Result listAddr(){List<Address> list = new ArrayList<>();Address addr = new Address();addr.setProvince("广东");addr.setCity("深圳");Address addr2 = new Address();addr2.setProvince("陕西");addr2.setCity("西安");list.add(addr);list.add(addr2);return Result.success(list);}
}