java读取服务器json文件并写入到本地

public class Product {
    public String Id;
    public String ProductName;
    public Product(String id,String productName)
    {
        this.Id=id;
        this.ProductName=productName;
    }

    public static ArrayList<Product> parseList(String response) {

        ArrayList<Product> products=new ArrayList<Product>();
        JSONArray arrayProduct = null;
        try {
            arrayProduct = new JSONArray(response);
            for (int i=0;i<arrayProduct.length();i++){
                String id=   arrayProduct.getJSONObject(i).getString("id");
                String name=   arrayProduct.getJSONObject(i).getString("name");
                products.add(new Product(id,name));
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return products;
    }
}

 　　private Handler mHandler = new Handler(Looper.getMainLooper());
    private void readNetJson()
    {
        AppUpdater.getInstance().getNetManager().get(APP_VERSION_URL, new INetCallBack() {
            @Override
            public void success(String response) {
                final ArrayList<Product> products = Product.parseList(response);
                if (products == null) {
                    mHandler.post(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(MainActivity.this, "服务器返回版本信息错误", Toast.LENGTH_SHORT).show();
                        }
                    });
                }
                //弹框显示版本信息
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            saveSingleJson(products);
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                });
            }

            @Override
            public void failed(Throwable throwable) {
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(MainActivity.this, "网络错误，更新版本失败", Toast.LENGTH_SHORT).show();
                    }
                });
            }
        }, MainActivity.this);


    }

private void saveSingleJson(ArrayList<Product> products) throws IOException {
        Toast.makeText(this, "保存独立Json文件", Toast.LENGTH_LONG).show();

        //json数据
        //products=new  ArrayList<Product>();
        //products.add(new Product("96356170", "明月端0001"));
        //打开要写入的json文件
        FileOutputStream fos =new FileOutputStream(jsonFile);
        //创建JsonWrite对象
        JsonWriter writer =new JsonWriter(new OutputStreamWriter(fos, "utf-8"));
        writer.setIndent("  ");
        writer.beginArray();
        for (Product product:products){
            writer.beginObject();
            writer.name("id").value(product.Id);
            writer.name("name").value(product.ProductName);
            writer.endObject();
        }
        writer.endArray();
        writer.close();
    }

private void readSingleJson() throws IOException {
        FileInputStream fis =new FileInputStream(jsonFile);
        JsonReader reader =new JsonReader(new InputStreamReader(fis,"utf-8"));
        products =new  ArrayList<Product>();
        reader.beginArray();
        while (reader.hasNext()){
            String id = "";
            String name = "";
            reader.beginObject();
            while (reader.hasNext()) {
                String field = reader.nextName();
                if (field.equals("id")){
                    id = reader.nextString();
                }else if (field.equals("name")){
                    name = reader.nextString();
                }else{
                    reader.skipValue();
                }
            }
            reader.endObject();
            products.add(new Product(id, name));
        }
        reader.endArray();
        reader.close();

        if (products != null) {
            ttvwJson.setText(products.size()+"");
        }
    }