一般接口我们都要定义统一的输入和输出，以及相应的接口文档。 新建ServerResponse类和 ResponseMessage 类，其中 ServerResponse 类用于作为每个API 接口的输出类型， ResponseMessage 作为枚举类，定义每一次操作的类型。 因为这里涉及到了序列化和反序列化，需要引入 jackson-databind 依赖

    1. <!-- jackson-databind -->
    2.     <dependency>
    3.       <groupId>com.fasterxml.jackson.core</groupId>
    4.       <artifactId>jackson-databind</artifactId>
    5.       <version>2.11.0</version>
    6.       <type>bundle</type>
    7.     </dependency>

    然后定义 ServerResponse.java 类

    package com.example.common;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@JsonInclude(JsonInclude.Include.NON_NULL)
public class ServerResponse <T> {
    private Logger logger = LoggerFactory.getLogger(getClass());

    @JsonProperty("status")
    private int statusCode;

    @JsonProperty("message")
    private String message;

    @JsonProperty("data")
    private T data;

    public void setData(T data) {
        this.data = data;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public void setStatusCode(int statusCode) {
        this.statusCode = statusCode;
    }

    public ServerResponse(int statusCode){
        this.statusCode = statusCode;
    }
    public ServerResponse(int statusCode, String message){
        this(statusCode);
        this.message = message;
    }
    public ServerResponse(int statusCode, String message, T data) {
        this(statusCode, message);
        this.data = data;
    }
    public  ServerResponse(int statusCode, T data) {
        this(statusCode);
        this.data = data;
    }

    public static <T> ServerResponse <T> setMessage (int statusCode, String message){
        return new ServerResponse(statusCode, message);
    }

    public  static <T> ServerResponse <T> setDetailMessage(int statusCode, T data){
        return new ServerResponse(statusCode, data);
    }
}

    然后是 ResponseMessage 类

    package com.example.common;

public enum ResponseMessage {
    SUCCESS(0,"SUCCESS"),
    LOGINSUCCESS(100,"登录成功！"),
    LOGINFAILED(101, "登录失败"),
    REGISTERSUCCESS(200,"注册成功"),
    REGISTERFAILED(201,"注册失败"),
    ERROR(1,"ERROR"),
    NEED_LOGIN(10,"NEED_LOGIN"),
    ILLEGAL_ARGUMENT(3,"ILLEGAL_ARGUMENT");

    private final int code;
    private final String desc;

    ResponseMessage(int code,String desc){
        this.code = code;
        this.desc = desc;
    }

    public int getCode() {
        return code;
    }

    public String getDesc() {
        return desc;
    }
}

    然后新建一个 UserController.java 来试一下

    package com.example.controller;

import com.example.common.ResponseMessage;
import com.example.common.ServerResponse;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api")
public class UserController {
    @GetMapping("/ping")
    public ServerResponse ping(){
        return ServerResponse.setMessage(ResponseMessage.SUCCESS.getCode(), ResponseMessage.SUCCESS.getDesc());
    }
}

    测试成功
    image.png