json Gson

时间 2019-11-29

标签 json gson 栏目 JavaScript 繁體版

原文原文链接


package com.example.volleylearn;

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

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

import android.test.AndroidTestCase;
import android.util.Log;

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

/*
1. 将json格式的字符串{}转换为Java对象, 使用原生API
2. 将json格式的字符串{}转换为Java对象, 使用GSON
3. 将json格式的字符串[]转换为Java对象的List, 使用原生API
4. 将json格式的字符串[]转换为Java对象的List, 使用GSON

5. 将Java对象转换为json字符串{}, 使用GSON
6. 将Java对象的List转换为json字符串[], 使用GSON
 */
public class JsonTest extends AndroidTestCase{

    /*
     * 1. 将json格式的字符串{}转换为Java对象, 使用原生API
     */
    public void testJsonToObject() throws JSONException {
        String jsonString = "{\"id\":2, \"name\":\"大虾\", \"price\":12.3,\"imagePath\":\"http://192.168.10.165:8080/L05_Server/images/f1.jpg\"}";
        
        //将json字符串封装为JSONObject对象
        JSONObject jsonObject = new JSONObject(jsonString);
        //从对象中根据key获得对应的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, name, price, imagePath);
        
        Log.e("TAG", shopInfo.toString());
    }
    
    /*
     * 1. 将json格式的字符串{}转换为Java对象, 使用GSON
     */
    public void testJsonToObject2()  {
        String jsonString = "{\"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(jsonString, ShopInfo.class);
        
        Log.e("TAG", shopInfo.toString());
    }
    
    
    /*
     * 3. 将json格式的字符串[]转换为Java对象的List, 使用原生API
     */
    public void testJsonToList() throws JSONException {
        String jsonString = "[{\"id\":3, \"name\":\"大虾\", \"price\":12.3,\"imagePath\":\"http://192.168.10.165:8080/L05_Server/images/f1.jpg\"},"
                + "{\"id\":5, \"name\":\"大虾2\", \"price\":128.3,\"imagePath\":\"http://192.168.10.165:8080/L05_Server/images/f2.jpg\"}]";
        List<ShopInfo> list = new ArrayList<ShopInfo>();
        
        //1. 将json字符串包装JSONArray对象
        JSONArray jsonArray = new JSONArray(jsonString);
        //2. 遍历JSONArray对象全部元素(JSONObject), 并将每一个元素封装为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获得对应的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, name, price, imagePath);
            list.add(shopInfo);
        }
        
        Log.e("TAG", list.toString());
    }
    
    /*
     * 4. 将json格式的字符串[]转换为Java对象的List, 使用GSON
     */
    public void testJsonToList2() throws JSONException {
        String jsonString = "[{\"id\":4, \"name\":\"大虾\", \"price\":12.3,\"imagePath\":\"http://192.168.10.165:8080/L05_Server/images/f1.jpg\"},"
                + "{\"id\":6, \"name\":\"大虾2\", \"price\":128.3,\"imagePath\":\"http://192.168.10.165:8080/L05_Server/images/f2.jpg\"}]";
        
        List<ShopInfo> list = new Gson().fromJson(jsonString, new TypeToken<List<ShopInfo>>(){}.getType());
        
        Log.e("TAG", list.toString());
    }
    
    /*
        5. 将Java对象转换为json字符串{}, 使用GSON
    */
    public void testObjectToJson() {
        ShopInfo info = new ShopInfo(3, "KK", 1000, "http://www.sina.com");
        String json = new Gson().toJson(info);
        Log.e("TAG", json);
    }
    
    
    /*
        6. 将Java对象的List转换为json字符串[], 使用GSON
    */
    
    public void testListToJson() {
        
        List<ShopInfo> list = new ArrayList<ShopInfo>();
        list.add(new ShopInfo(3, "KK", 1000, "http://www.sina.com"));
        list.add(new ShopInfo(4, "KK2", 2000, "http://www.sina.com222"));
        
        String json = new Gson().toJson(list);
        
        Log.e("TAG", json);
    }
    
    public void testJsonToMap() {
        String jsonString = "{\"my name\":\"大虾\", \"1\":12}";
        Map<String, Object> map = new Gson().fromJson(jsonString, new TypeToken<Map<String, Object>>(){}.getType());
        Log.e("TAG", map.toString());
    }
}

FastJson  
  // （4）将Java对象的List转换为json字符串[]
    private void javaToJsonArrayByFastJson() {

        // 1 建立一个Java集合
        List<ShopInfo> shops = new ArrayList<>();

        ShopInfo baoyu = new ShopInfo(1, "鲍鱼", 250.0, "baoyu");
        ShopInfo longxia = new ShopInfo(2, "龙虾", 251.0, "longxia");

        shops.add(baoyu);
        shops.add(longxia);

        // 2 生成JSON数据
        String json = JSON.toJSONString(shops);

    }

    // （3）将Java对象转换为json字符串{}
    private void javaToJsonObjectByFastJson() {

        // 1 建立一个Java对象
        ShopInfo shopInfo = new ShopInfo(1, "鲍鱼", 250.0, "baoyu");

        // 2 生成JSON数据
        String json = JSON.toJSONString(shopInfo);
    }


    // （2）将json格式的字符串[]转换为Java对象的List
    private void jsonToJavaListByFastJson() {

        // 1 获取或建立json数据
        String json = "[\n" +
                "    {\n" +
                "        \"id\": 1,\n" +
                "        \"imagePath\": \"http://192.168.10.165:8080/f1.jpg\",\n" +
                "        \"name\": \"大虾1\",\n" +
                "        \"price\": 12.3\n" +
                "    },\n" +
                "    {\n" +
                "        \"id\": 2,\n" +
                "        \"imagePath\": \"http://192.168.10.165:8080/f2.jpg\",\n" +
                "        \"name\": \"大虾2\",\n" +
                "        \"price\": 12.5\n" +
                "    }\n" +
                "]";

       // 2 解析JSON数据
        List<ShopInfo> shopInfos = JSON.parseArray(json, ShopInfo.class);

    }

    // （1）将json格式的字符串{}转换为Java对象
    private void jsonToJavaObjectByFastJson() {

        // 1 获取或建立json数据
        String json = "{\n" +
                "\t\"id\":2, \"name\":\"大虾\", \n" +
                "\t\"price\":12.3, \n" +
                "\t\"imagePath\":\"http://192.168.10.165:8080/L05_Server/images/f1.jpg\"\n" +
                "}\n";

        // 2 解析JSON数据
        ShopInfo shopInfo = JSON.parseObject(json, ShopInfo.class);
    }
}