java基础之泛型对象与json互转

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1. 场景描述

把泛型对象转成字符串放到缓存中，获取后使用有点问题，记录下，有碰到的朋友，参考下。

2. 解决方案

2.1 操作类及说明

    /**

     * @auther: 软件老王

     */

 public static void main(String[] args) {

        VO<UserParm> vo = new VO<UserParm>();

        UserParm user = new UserParm();

        user.setUserIdName("1111");

        user.setMobilePhoneNo("2222");

        vo.setData(user);

        //正常情况

        //1.对象转json str

        String str = JSONObject.toJSONString(vo);

        System.out.println(str);

        //2,json str 转对象

        VO vojs= JSONObject.parseObject(str,VO.class);

        System.out.println(vojs);

        //泛型 不能使用强转，不管用，报错

        VO<UserParm> vojs2= JSONObject.parseObject(str,VO.class);

        System.out.println(vojs2);

//        System.out.println(vojs2.getData().getMobilePhoneNo());

        //泛型，正常转换

        VO<UserParm> vojs3= JSONObject.parseObject(str,new TypeReference<VO<UserParm>>(){});

        System.out.println(vojs3.getData().getMobilePhoneNo());

    }

说明：

（1）用的是阿里的fastjson，pom文件中增加下依赖

       <dependency>

            <groupId>com.alibaba</groupId>

            <artifactId>fastjson</artifactId>

            <version>1.2.46</version>

        </dependency>

（2）对象转json格式str

 String str = JSONObject.toJSONString(vo);  //软件老王

（3）json格式str转对象

 VO vojs= JSONObject.parseObject(str,VO.class); //软件老王

（4）泛型的不一样，转换为泛型对象UserParm的时候会报错。

System.out.println(vojs2.getData().getMobilePhoneNo());

com.alibaba.fastjson.JSONObject cannot be cast to com.laowang.spcrud.entity.UserPar

泛型的需要使用TypeReference才行：

   VO<UserParm> vojs3= JSONObject.parseObject(str,new TypeReference<VO<UserParm>>(){});

（5）结果展示

com.laowang.spcrud.service.TestService

{"code":"0","data":{"mobilePhoneNo":"2222","userIdName":"1111"}}

com.laowang.spcrud.entity.VO@368239c8

com.laowang.spcrud.entity.VO@9e89d68

2222

Process finished with exit code 0

2.2 两个对象类

（1）泛型类VO

package com.laowang.spcrud.entity;

import java.io.Serializable;

/**

* @auther: 软件老王

*/

public class VO<T> implements Serializable {

    public static final String SUCCESS = "0";

    public static final String FAIL = "1";

    private static final long serialVersionUID = 1L;

    private String code = SUCCESS;

    private String msg;

    private T data;

    public static String getSUCCESS() {

        return SUCCESS;

    }

    public static String getFAIL() {

        return FAIL;

    }

    public static long getSerialVersionUID() {

        return serialVersionUID;

    }

    public String getCode() {

        return code;

    }

    public void setCode(String 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;

    }

}

（2）实体类UserParm

package com.laowang.spcrud.entity;

import java.io.Serializable;

/**

* @auther: 软件老王

*/

public class UserParm implements Serializable {

    private static final long serialVersionUID = 1L;

    private String mobilePhoneNo;

    private String email;

    private String uid;

    private String userIdName;

    public static long getSerialVersionUID() {

        return serialVersionUID;

    }

    public String getMobilePhoneNo() {

        return mobilePhoneNo;

    }

    public void setMobilePhoneNo(String mobilePhoneNo) {

        this.mobilePhoneNo = mobilePhoneNo;

    }

    public String getEmail() {

        return email;

    }

    public void setEmail(String email) {

        this.email = email;

    }

    public String getUid() {

        return uid;

    }

    public void setUid(String uid) {

        this.uid = uid;

    }

    public String getUserIdName() {

        return userIdName;

    }

    public void setUserIdName(String userIdName) {

        this.userIdName = userIdName;

    }

}