java中统一返回前端格式及统一结果处理返回详解

// 举例：返回结果样式
{
  "success": true,
  "code": 200,
  "message": "查询用户列表",
  "data": {
    "itms": [
      {
        "id": "1",
        "username": "admin",
        "role": "ADMIN",
        "createTime": "2020-4-24T15:32:29",
        "modifiedTime": "2020-4-24T15:41:40"
      },{
        "id": "2",
        "username": "zhangsan",
        "role": "USER",
        "createTime": "2020-4-24T15:32:29",
        "modifiedTime": "2020-4-24T15:41:40"
      }
    ]
  }
}

@Data
public class Result {
    private Boolean success;
    private Integer code;
    private String message;
    private Map<String, Object> data = new HashMap<>();
    
    // 默认私有构造器
    private Result(){
        
    }
    
    // 自定义构造器
    private Result(Boolean success, Integer code, String message){
        this.success = success;
        this.code = code;
        this.message = message;
    }
    
    
    
    // 返回一个默认的 成功操作 的实例对象，默认响应状态码 200
    public static Result ok(){
        // 使用 HttpStatus 的常量表示响应状态码，这个需要导入 httpcore 依赖
        return new Result(true, HttpStatus.SC_OK, "success");
    }
    
    // 返回一个自定义 成功操作 的实例对象
    public static Result ok(Boolean success, Integer code, String message) {
        return new Result(success, code, message);
    }
    
    
    
    // 返回一个默认的 失败操作 的结果，默认响应状态码为 500
    public static Result error() {
        return new Result(false, HttpStatus.SC_INTERNAL_SERVER_ERROR, "error");
    }
    
    // 返回一个自定义 失败操作 的实例对象
    public static Result error(Boolean success, Integer code, String message) {
        return new Result(success, code, message);
    }
    
    
    
    // 自定义响应是否成功
    public Result success(Boolean success) {
        this.setSuccess(success);
        return this;
    }
    
    // 自定义响应状态码
    public Result code(Integer code) {
        this.setCode(code);
        return this;
    }
    
    // 自定义响应消息
    public Result message(String message) {
        this.setMessage(message);
        return this;
    }
    
    // 自定义响应数据，一次设置一个 map 集合
    public Result data(Map<String, Object> map) {
        this.data.putAll(map);
        return this;
    }
    
    // 通用设置响应数据，一次设置一个 key - value 键值对
    public Result data(String key, Object value) {
        this.data.put(key, value);
        return this;
    }
}

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpcore</artifactId>
    <version>4.4.13(版本号)</version>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.12</version>
    <scope>provided</scope>
</dependency>

@GetMapping("selectOne")
public Result selectOne(Integer id) {
    Emp emp = this.empService.queryById(id);
    if (emp == null) {
        return Result.error().message("用户不存在");
    }
    return Result.ok().data("items", emp).message("查询成功");
}

{
    "success": true,
    "code": 200,
    "message": "查询成功",
    "data": {
        "items": {
            "id": 1,
            "name": "tom",
            "salary": 6000.0,
            "age": 20,
            "email": "tom@163.com"
        }
    }
}

{
    "success": false,
    "code": 500,
    "message": "用户不存在",
    "data": {}
}