JsonResult-马育民老师

# 说明

controller 返回给前端的封装类，有以下成员变量：

- `code`：`int` 类型，状态码，0表示成功，非0表示错误，每类错误都有错误码
- `msg`：`String` 类型，文字描述，如：`添加成功！`
- `data`：泛型，数据，如：从数据库查询的数据，放到 data中，传给前端

### 依赖

- jackson：用于转成json

- [JsonCodeMsg](//www.malaoshi.top/show_1IX71bLLsAgz.html "JsonCodeMsg")：封装常用的 `code` 和 `msg`

### 代码

```
package top.malaoshi.netdisk.vo;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
@JsonInclude(JsonInclude.Include.NON_NULL)
public class JsonResult<T> {
    private int code;
    private String msg;
    private T data;
    public JsonResult(int code,String msg){
        this.code=code;
        this.msg=msg;
    }

/**
     * 校验失败
     * @param msg
     * @return
     */
    public static JsonResult validateFail(String msg){
        JsonResult jr=new JsonResult(JsonCodeMsg.VALIDATE_FAIL.getCode(), msg);
        return jr;
    }
    /**
     * 服务器出现错误
     * @return
     */
    public static JsonResult serverError(){
        JsonResult jr=new JsonResult(JsonCodeMsg.SERVER_ERROR.getCode(), JsonCodeMsg.SERVER_ERROR.getMsg());
        return jr;
    }
    /**
     * 服务器出现错误
     * @return
     */
    public static JsonResult serverError(String msg){
        JsonResult jr=new JsonResult(JsonCodeMsg.SERVER_ERROR.getCode(),msg);
        return jr;
    }
    /**
     * 表示执行成功
     * @param msg
     * @param data 数据
     * @return
     */
    public static JsonResult success(String msg,Object data){
        JsonResult jr=new JsonResult(JsonCodeMsg.SUCCESS.getCode(), msg);
        jr.setData(data);
        return jr;
    }
    public static JsonResult success(String msg){
        JsonResult jr=new JsonResult(JsonCodeMsg.SUCCESS.getCode(),msg);
        return jr;
    }

/**
     * 操作失败
     * @param code
     * @param msg
     * @return
     */
    public static JsonResult fail(int code,String msg){
        JsonResult jr=new JsonResult(code,msg);
        return jr;
    }
    public String toJSON() throws JsonProcessingException {
        ObjectMapper om=new ObjectMapper();
        String jsonStr=om.writeValueAsString(this);
        return jsonStr;
    }
    public T getData() {
        return data;
    }
    public void setData(T data) {
        this.data = data;
    }
    public int getCode() {
        return code;
    }
    public void setCode(int code) {
        this.code = code;
    }
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
}

```

原文出处：http://www.malaoshi.top/show_1IX2rn0kwlcB.html