远程服务器存储之JSON

一.特点

    1.JavaScript Object Notation

    2.一种轻量级的数据交互格式

二.格式

    1.[ ] 数组:[value1, value2, value3...]

    2.{ } 对象:{key1:value1, key2:value2, key3:value3,...}

      1-key:字符串,表示对象的属性

      2-value:表示属性的值

         数据类型：数值，字符串，null，json数组，json对象。

三.API

   1.Android原生

   2.第三方框架

 JSON代码展示：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.hanqi.testapp3.TestActivity4"
    android:orientation="vertical">

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Android原生解析JSON转对象"
        android:onClick="bt1_OnClick"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Gson解析JSON转对象"
        android:onClick="bt2_OnClick"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Android原生解析JSON转集合"
        android:onClick="bt3_OnClick"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Gson解析JSON转集合"
        android:onClick="bt4_OnClick"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Gson解析JSON之对象转JSON"
        android:onClick="bt5_OnClick"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Gson解析JSON之集合转JSON"
        android:onClick="bt6_OnClick"/>




    <EditText
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:id="@+id/et_3"/>


</LinearLayout>

package com.hanqi.testapp3;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

public class TestActivity4 extends AppCompatActivity {

    EditText et_3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test4);

        et_3=(EditText)findViewById(R.id.et_3);

    }

    //原生从Json字符串转成对象
    public void bt1_OnClick(View v)
    {

        String strJson="{"id":1,"name":"大虾", " +
                ""price":12.3, " +
                ""imagePath":"http://192.168.10.165:8080/L05_Server/images/f1.jpg"}";

        //从Json字符串转成对象
        try {
            JSONObject jo = new JSONObject(strJson);

            int id=jo.getInt("id");
            String name=jo.getString("name");
            double price=jo.getDouble("price");
            String imagePath=jo.getString("imagePath");

            ShopInfo shopInfo=new ShopInfo(id,imagePath,name,price);

            et_3.setText(shopInfo.toString());


        }
        catch (Exception e)
        {
            e.printStackTrace();
        }


    }

    //Gson转对象
    public void bt2_OnClick(View v)
    {
        //转对象
        String jsonstr="{"id":3,"name":"大虾"," +
                ""price":12.3," +
                ""imagePath":"http://192.168.10.165:8080/L05_Server/images/f1.jpg"}";

        ShopInfo shopInfo=new Gson().fromJson(jsonstr,ShopInfo.class);

        et_3.setText(shopInfo.toString());

//        //转集合
//        String jsonstr1="[{"id":3, "name":"大虾1", "price":12.3, " +
//                ""imagePath":"http://192.168.10.165:8080/f1.jpg"}," +
//                "{"id":4, "name":"大虾2", "price":12.5, " +
//                ""imagePath":"http://192.168.10.165:8080/f2.jpg"}]";
//
//        List<ShopInfo> list=new Gson().fromJson(jsonstr1, new TypeToken<List<ShopInfo>>() {
//        }.getType());
//
//        et_3.setText(list.toString());
//
//        //对象转JSON
//        ShopInfo info=new ShopInfo(3,"http://www.sina.com","KK",1000);
//
//        String json=new Gson().toJson(info);
//
//        et_3.setText(json);
//
//        //集合转JSON
//        List<ShopInfo> list1=new ArrayList<ShopInfo>();
//
//        list1.add(new ShopInfo(3, "http://www.sina.com","KK", 1000));
//        list1.add(new ShopInfo(4, "http://www.sina.com/cn", "KK1", 2000));
//        String json1=new Gson().toJson(list1);
//
//        et_3.setText(json1);

//        String jsonstr2="{"my name":"大虾","1":12}";
//
//        Map<String,Object> map=new Gson().fromJson(jsonstr2,new TypeToken<Map<String,Object>>(){}.getType());
//
//        et_3.setText(map.toString());

    }

    //原生从Json字符串转成集合
    public void bt3_OnClick(View v)
    {

        //转集合
        String jsonstr="[{"id":1,"name":"大虾1","price":12.3," +
                " "imagePath":"http://192.168.10.165:8080/f1.jpg"}," +
                "{"id":2, "name":"大虾2", "price":12.5, " +
                ""imagePath":"http://192.168.10.165:8080/f2.jpg"}]";

        //从Json字符串转成集合
        try {

            List<ShopInfo> list=new ArrayList<ShopInfo>();

            //1.将json字符串包装JSONArray对象
            JSONArray jsonArray=new JSONArray(jsonstr);

            //2.遍历JSONArray对象所有元素（JSONObject），并将每个元素封装为shopInfo，并添加到list
            for (int i=0;i<jsonArray.length();i++)
            {
                JSONObject jsonObject=jsonArray.getJSONObject(i);

                //从对象中根据key得到相应的value
                int id=jsonObject.getInt("id");
                String name=jsonObject.getString("name");
                double price=jsonObject.getDouble("price");
                String imagePath=jsonObject.getString("imagePath");

                //封装ShopInfo对象
                ShopInfo shopInfo=new ShopInfo(id,imagePath,name,price);

                list.add(shopInfo);

            }

            et_3.setText(list.toString());


        }
        catch (Exception e)
        {
            e.printStackTrace();
        }


    }


    //Gson转集合
    public void bt4_OnClick(View v)
    {
        //转集合
        String jsonstr="[{"id":3, "name":"大虾1", "price":12.3, " +
                ""imagePath":"http://192.168.10.165:8080/f1.jpg"}," +
                "{"id":4, "name":"大虾2", "price":12.5, " +
                ""imagePath":"http://192.168.10.165:8080/f2.jpg"}]";

        List<ShopInfo> list=new Gson().fromJson(jsonstr, new TypeToken<List<ShopInfo>>() {
        }.getType());

        et_3.setText(list.toString());


    }


    //Gson对象转JSON
    public void bt5_OnClick(View v)
    {
        //对象转JSON
        ShopInfo info=new ShopInfo(3,"http://www.sina.com","KK",1000);

        String json=new Gson().toJson(info);

        et_3.setText(json);


    }

    //Gson集合转JSON
    public void bt6_OnClick(View v)
    {
        //集合转JSON
        List<ShopInfo> list=new ArrayList<ShopInfo>();

        list.add(new ShopInfo(3, "http://www.sina.com","KK", 1000));
        list.add(new ShopInfo(4, "http://www.sina.com/cn", "KK1", 2000));
        String json=new Gson().toJson(list);

        et_3.setText(json);


    }


}