JSON解析(使用框架解析)

• 使用Gson框架解析

Demo展示:

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

        // 1 获取或创建Java对象
        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
        Gson gson = new Gson();
        String json = gson.toJson(shops);
    }

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

        // 1 获取或创建Java对象
        ShopInfo shopInfo = new ShopInfo(1,"鲍鱼",250.0,"baoyu");

        // 2 生成JSON数据
        Gson gson = new Gson();
        String json = gson.toJson(shopInfo);
    }

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

        // 1 获取或创建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
        Gson gson = new Gson();
        List<ShopInfo> shops = gson.fromJson(json, new TypeToken<List<ShopInfo>>() {
        }.getType());
    }

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

        // 1 获取或创建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
        Gson gson = new Gson();
        ShopInfo shopInfo = gson.fromJson(json, ShopInfo.class);
    }

bean类:

package com.atguigu.android.json.bean;

/**
 * Created by Administrator on 2016/8/27 0027.
 */
// 商店的实体类
public class ShopInfo {
    private int id;
    private String name;
    private double price;
    private String imagePath;

    public ShopInfo(int id, String name, double price, String imagePath) {
        this.id = id;
        this.name = name;
        this.price = price;
        this.imagePath = imagePath;
    }

    public ShopInfo() {
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public String getImagePath() {
        return imagePath;
    }

    public void setImagePath(String imagePath) {
        this.imagePath = imagePath;
    }

    @Override
    public String toString() {
        return "ShopInfo{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", price=" + price +
                ", imagePath='" + imagePath + '\'' +
                '}';
    }
}

注意:要求json对象中的key的名称与java对象对应的类中的属性名要相同

• 使用FastJson框架解析

Fastjson是一个Java语言编写的高性能功能完善的JSON库。它采用一种“假定有序快速匹配”的算法，把JSON Parse的性能提升到极致，是目前Java语言中最快的JSON库。

Demo展示:

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

        // 1 创建一个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 创建一个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 获取或创建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 获取或创建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);
    }