网络通信——HTTP接口访问——移动数据格式JSON

Myth丶恋晨 2024-04-03 12:50 96阅读 0赞

![05585196d76b30086b9b6d93d8d80064.png][]

网络通信的交互数据格式有两大类，分别是JSON和XML 。

对于App来说，基本采用JSON格式与服务器通信。

JSON相比XML的优势主要有两个：(1)手机流量很贵，表达同样的信息，JSON串比XML串短很多。(2) JSON串解析得更快，也更省电，XML不但慢而且耗电。

![b16aff48feca629498614b09e7b8ade7.png][]

(1)整个JSON串由一对花括号包裹，并且内部的每个结构都以花括号包起来；(2)参数格式类似键值对，其中键名与键值之间以冒号分隔，形如“键名:键值”；(3)两个键值对之间以逗号分隔；(4)键名需要用双引号括起来，键值为数字的话则无需双引号，为字符串的话仍需双引号；(5)JSON数组通过方括号表达，方括号内部依次罗列各个元素，具体格式形如“数组的键名:\[元素1,元素2,元素3\]”；

![7362793ef05b85a6cd4a445d23cb6178.png][]

![eb9798270f3e586c872a131e6ef0068f.png][]

================================================================================================

引入：

// https://mvnrepository.com/artifact/com.google.code.gson/gson
    implementation group: 'com.google.code.gson', name: 'gson', version: '2.8.8'

布局：

![3ebbfbc9cbe0c406b620dba88a2750bd.png][]

UserInfo

package com.example.myapplication.bean;
    
    public class UserInfo 
    {
        public String name; // 姓名
        public int age; // 年龄
        public long height; // 身高
        public float weight; // 体重
        
        public UserInfo(String name, int age, long height, float weight) 
        {
            this.name = name;
            this.age = age;
            this.height = height;
            this.weight = weight;
        }
        
    }

主代码;

package com.example.myapplication;
    
    import android.os.Bundle;
    import android.view.View;
    import android.widget.TextView;
    
    import androidx.appcompat.app.AppCompatActivity;
    
    import com.example.myapplication.bean.UserInfo;
    import com.google.gson.Gson;
    
    public class MainActivity extends AppCompatActivity implements View.OnClickListener
    {
    
        private TextView tv_json; // 声明一个文本视图对象
        private UserInfo mUser; // 声明一个用户信息对象
        private String mJsonStr; // JSON格式的字符串
    
        @Override
        protected void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            mUser = new UserInfo("asi", 25, 165L, 50.0f); // 创建用户实例
            mJsonStr = new Gson().toJson(mUser); // 把用户实例转换为JSON串
    
            tv_json = findViewById(R.id.tv_json);
    
            findViewById(R.id.btn_origin_json).setOnClickListener(this);
            findViewById(R.id.btn_convert_json).setOnClickListener(this);
        }
    
        @Override
        public void onClick(View v)
        {
            if (v.getId() == R.id.btn_origin_json)
            {
    
                mJsonStr = new Gson().toJson(mUser); // 把用户实例转换为JSON字符串
                tv_json.setText("JSON串内容如下：\n" + mJsonStr);
            }
            else if (v.getId() == R.id.btn_convert_json)
            {
    
                // 把JSON串转换为UserInfo类型的对象
                UserInfo newUser = new Gson().fromJson(mJsonStr, UserInfo.class);
    
                String desc = String.format("\n\t姓名=%s\n\t年龄=%d\n\t身高=%d\n\t体重=%f", newUser.name, newUser.age, newUser.height, newUser.weight);
    
                tv_json.setText("从JSON串解析而来的用户信息如下：" + desc);
            }
        }
    
    }

![542c018a280451738a605271ffc4c42a.png][]

![d8171a0d9de3964c61a9805dbc2ba31c.png][]

![5f8dca16c4b16326b4093d3df37ba545.png][]

![85561caba0cbfe22b3cb29301c830a9d.png][]

![916548a05fb79c4b6b274f1e4705196f.png][]

![86c12e62dda49b3a1ef851fa0f6dc990.png][]

![6533c1087875b7f726d9ca92323cce51.png][]

![bc7142785f2461914258c10affac896f.png][]

[05585196d76b30086b9b6d93d8d80064.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/c49b47c81d964f07a1b8d456ecd713c1.png
[b16aff48feca629498614b09e7b8ade7.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/25b85c46217641a1b1454adac435ead5.png
[7362793ef05b85a6cd4a445d23cb6178.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/aff3bb70fcd949d2af7e71355a466dd6.png
[eb9798270f3e586c872a131e6ef0068f.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/30e4517ec23840818e6737b192669625.png
[3ebbfbc9cbe0c406b620dba88a2750bd.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/58dc797177b8456fa641e0c6c0b7449b.png
[542c018a280451738a605271ffc4c42a.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/d78dd90e869e4383845cf6ad1e1cbfad.png
[d8171a0d9de3964c61a9805dbc2ba31c.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/08135f1582bc4b6294f735efe7a32663.png
[5f8dca16c4b16326b4093d3df37ba545.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/f3c0e3c1d9c64cefb3d1ebaca125367c.png
[85561caba0cbfe22b3cb29301c830a9d.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/461f8b4461f845b3ac77f66bc835b714.png
[916548a05fb79c4b6b274f1e4705196f.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/0301b4b75fda431dbe5b428c77b00537.png
[86c12e62dda49b3a1ef851fa0f6dc990.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/fb221cb3fff94261bf185f497bfb5c6e.png
[6533c1087875b7f726d9ca92323cce51.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/6ecffae159e6458b84b75818e0345240.png
[bc7142785f2461914258c10affac896f.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/03/32446a6e1702493c965a9d0b29f2ab89.png