0、前言

  开发系统中,前后端分离,后端一般返回RESTfull  API,前端调用API构建UI,彼此分离、互相完全独立;

  后台API中,我们一般返回结果码、提示信息、数据三部分内容,如图:

 我们今天就来构建一个完整的前后端分离后端的API

一、RESTfull API构建

1、增加结果码接口 IErrorCode 

package com.anson.common.result;
/**
 * @Author anson
 * @Description 1、结果码接口
 * @Date 2019/12/10 10:50
*/
public interface IErrorCode {
    long getCode();
    String getMessage();
}

2、添加结果消息枚举 ResultCode  

package com.anson.common.result;

/**
 * @Author anson
 * @Description 结果消息枚举
 * @Date 2019/12/10 22:05
*/
public enum ResultCode  implements IErrorCode
{
    // 数据操作消息定义
    SUCCESS(200, "成功!"),
    BODY_NOT_MATCH(400,"请求的数据格式不符!"),
    UNAUTHORIZED(401,"暂未登录或token已经过期!"),
    FORBIDDEN(403, "没有相关权限"),
    NOT_FOUND(404, "未找到该资源!"),
    FAILED(500, "服务器内部错误!"),
    SERVER_BUSY(503,"服务器正忙,请稍后再试!");

    private long code;
    private String message;

    private ResultCode(long code, String message) {
        this.code = code;
        this.message = message;
    }

    public long getCode() {
        return code;
    }

    public String getMessage() {
        return message;
    }
}

3、添加返回结果实体 ResultBody

package com.anson.common.result;

/**
 * @description: API返回结果实体
 * @author: anson
 * @Date: 2019/12/10 10:54
 */


public class ResultBody<T>
{
    private long code;
    private String message;
    private T data;

    protected ResultBody() {
    }

    protected ResultBody(long code, String message, T data) {
        this.code = code;
        this.message = message;
        this.data = data;
    }

    /**
     * 成功返回结果
     *
     * @param data 获取的数据
     */
    public static <T> ResultBody<T> success(T data) {
        return new ResultBody<T>(ResultCode.SUCCESS.getCode(), ResultCode.SUCCESS.getMessage(), data);
    }

    /**
     * 成功返回结果
     *
     * @param data    获取的数据
     * @param message 提示信息
     */
    public static <T> ResultBody<T> success(T data, String message) {
        return new ResultBody<T>(ResultCode.SUCCESS.getCode(), message, data);
    }

    /**
     * 失败返回结果
     *
     * @param errorCode 错误码
     */
    public static <T> ResultBody<T> failed(IErrorCode errorCode) {
        return new ResultBody<T>(errorCode.getCode(), errorCode.getMessage(), null);
    }

    /**
     * 失败返回结果
     *
     * @param message 提示信息
     */
    public static <T> ResultBody<T> failed(String message) {
        return new ResultBody<T>(ResultCode.FAILED.getCode(), message, null);
    }

    /**
     * 失败返回结果
     */
    public static <T> ResultBody<T> failed() {
        return failed(ResultCode.FAILED);
    }

    /**
     * 参数验证失败返回结果
     */
    public static <T> ResultBody<T> validateFailed() {
        return failed(ResultCode.NOT_FOUND);
    }

    /**
     * 参数验证失败返回结果
     *
     * @param message 提示信息
     */
    public static <T> ResultBody<T> validateFailed(String message) {
        return new ResultBody<T>(ResultCode.NOT_FOUND.getCode(), message, null);
    }

    /**
     * 未登录返回结果
     */
    public static <T> ResultBody<T> unauthorized(T data) {
        return new ResultBody<T>(ResultCode.UNAUTHORIZED.getCode(), ResultCode.UNAUTHORIZED.getMessage(), data);
    }

    /**
     * 未授权返回结果
     */
    public static <T> ResultBody<T> forbidden(T data) {
        return new ResultBody<T>(ResultCode.FORBIDDEN.getCode(), ResultCode.FORBIDDEN.getMessage(), data);
    }

    public long getCode() {
        return code;
    }

    public void setCode(long code) {
        this.code = code;
    }

    public String getMessage() {
        return message;
    }

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

    public T getData() {
        return data;
    }

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

4、添加实体类、dao、service

略,具体看代码,跟前几节的一致

5、编写controller

    //--------------------------------API test-------------------

    //1、根据ID获取单个用户
    @ApiOperation(value = "获取用户", notes = "根据id查询用户信息")
    @ApiImplicitParam(name = "id", value = "用户id", required=true, dataType="int") //API参数
    @RequestMapping(value="/user/{id}",method= RequestMethod.GET)
    public ResultBody getUserById(int id)
    {
        User user = userservice.selectByPrimaryKey(id);
        return  ResultBody.success(user,"获取单个信息成功");
    }

    //2、获取所有用户
    @ApiOperation(value = "获取所有用户", notes = "获取所有用户")
    @RequestMapping(value="/userall",method= RequestMethod.GET)
    public ResultBody getUserAll()
    {
        List<User> users = userservice.getAll();
        return  ResultBody.success(users,"获取所有用户信息成功");
    }

好,完毕

二、运行测试,在swagger中执行测试,结果如下

{
  "code": 200,
  "data": [
    {
      "id": 1,
      "password": "123",
      "realname": "张三",
      "username": "anson"
    },
    {
      "id": 2,
      "password": "123",
      "realname": "李四",
      "username": "Alex"
    },
    {
      "id": 3,
      "password": "123",
      "realname": "王五",
      "username": "kks"
    },
    {
      "id": 4,
      "password": "000",
      "realname": "赵柳",
      "username": "eee"
    }
  ],
  "message": "获取所有用户信息成功"
}

GIT源码地址:https://github.com/anson-yang/cloverDemo.git

12-22 23:37