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 data

    public 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);
    }

    @Override
    public 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);
    }
}