Java后端返回Json数据规范

一，统一返回的Json数据格式

返回内容：

状态码，返回消息，数据

1.列表数据

{
  "success": true,
  "code": 20000,
  "message": "成功",
  "data": {
    "items": [
      {
        "id": "1",
        "name": "小王",
        "identified": "用户"
      }
    ]
  }
}

2.分页数据

{
  "success": true,
  "code": 20000,
  "message": "成功",
  "data": {
    "total": 17,
    "rows": [
      {
        "id": "1",
        "name": "小王",
        "identified": "用户"
      }
    ]
  }
}

3.无返回数据

{
  "success": true,
  "code": 20000,
  "message": "成功",
  "data": {}
}

4.返回数据失败

{
  "success": false,
  "code": 20001,
  "message": "失败",
  "data": {}
}

统一定义格式：

{
  "success": 布尔, //响应是否成功
  "code": 数字, //响应码
  "message": 字符串, //返回消息
  "data": HashMap //返回数据，放在键值对中
}

二，创建统一返回结果类

1.创建接口定义返回码

创建工具包utils，创建接口命名为ResultCode.java

package com.atguigu.commonutils;

public interface ResultCode {

    public static Integer SUCCESS = 20000;  //成功码

    public static Integer ERROR = 20001;  //失败码
}

2.创建结果类

创建类Result

@Data
public class Result {
    @ApiModelProperty(value = "是否成功")
    private Boolean success;

    @ApiModelProperty(value = "返回码")
    private Integer code;

    @ApiModelProperty(value = "返回消息")
    private String message;

    @ApiModelProperty(value = "返回数据")
    private Map<String, Object> data = new HashMap<String, Object>();

    private Result(){}

    public static Result ok(){
        Result r = new Result();
        r.setSuccess(true);
        r.setCode(ResultCode.SUCCESS);
        r.setMessage("成功");
        return r;
    }

    public static Result error(){
        Result r = new Result();
        r.setSuccess(false);
        r.setCode(ResultCode.ERROR);
        r.setMessage("失败");
        return r;
    }

    public Result success(Boolean success){
        this.setSuccess(success);
        return this;
    }

    public Result message(String message){
        this.setMessage(message);
        return this;
    }

    public Result code(Integer code){
        this.setCode(code);
        return this;
    }

    public Result data(String key, Object value){
        this.data.put(key, value);
        return this;
    }

    public Result data(Map<String, Object> map){
        this.setData(map);
        return this;
    }
}

3.Controller中的返回统一数据格式的Json示例

列表数据
在返回的json的中，有一个键值为data的Hashmap
使用mybatis plus无条件（wrapper为null，查询全部）查询所有用户的信息
所有信息返回一个list
将list放入hashmap中，键值为items

@ApiOperation(value = "所有列表")
@GetMapping("findAllTeacher")
public Result list(){
    List<Teacher> list = teacherService.list(null);
    return Result.ok().data("items", list);
}

空数据
这里是根据id删除用户信息，因此无返回数据

@ApiOperation(value = "根据ID删除")
@DeleteMapping("{id}")
public Result removeById(
    @ApiParam(name = "id", value = "ID", required = true)
    @PathVariable String id){
    teacherService.removeById(id);
    return Result.ok();
}