public class Result<T> {
    private Integer code;
    private String msg;
    private T data;

    public Result() {
        super();
    }

    public Result(Integer code, String msg, T 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 T getData() {
        return data;
    }

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

    @Override
    public String toString() {
        return "Result{" +
                "code=" + code +
                ", msg='" + msg + '\'' +
                ", data=" + data +
                '}';
    }
}

public enum ResultEnum {
    //这里是可以自己定义的，方便与前端交互即可
    UNKNOWN_ERROR(-1,"未知错误"),
    SUCCESS(200,"成功"),
    SERVER_INTERNAL_ERROR(500,"服务器内部错误"),
    RESOURCE_NOT_FOUND(404,"资源未找到"),
    PARAMETER_NOT_VALID(400,"参数不合法"),
    ;
    private Integer code;
    private String msg;

    ResultEnum(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    public Integer getCode() {
        return code;
    }

    public String getMsg() {
        return msg;
    }
}

public class ResultUtil {

    /**成功且带数据**/
    public static Result success(Object object){
        Result result = new Result();
        result.setCode(ResultEnum.SUCCESS.getCode());
        result.setMsg(ResultEnum.SUCCESS.getMsg());
        result.setData(object);
        return result;
    }
    /**成功但不带数据**/
    public static Result success(){

        return success(null);
    }
    /**失败**/
    public static Result error(Integer code,String msg){
        Result result = new Result();
        result.setCode(code);
        result.setMsg(msg);
        return result;
    }
}

//测试
@RequestMapping(value = "/list", method = RequestMethod.POST)
    public Result findCategoryByPid(@RequestBody Map map){
        map.get("parentId");
        List<Category> list = categoryService.findCategoryByPid(map);
        if (CollectionUtils.isEmpty(list)){
            return ResultUtil.error(404,"资源未找到到");
        }
        return ResultUtil.success(list);
    }