json 生成和解析

Gson

使用案例

//Gson
        //1 创建Gson对象
        Gson g = new Gson();
        //2 转换
        Book b1 = new Book("100","金苹果","种植苹果的故事");
        String s = g.toJson(b1);
        System.out.println(s);

        //3 转回对象
        Book b2 = g.fromJson(s,Book.class);
        System.out.println(b2.getId());

        //转为hash图
        HashMap data = g.fromJson(s, HashMap.class);
        System.out.println(data.get("id"));



        //{"id":"100","name":"金苹果","info":"种植苹果的故事","page":["123","456","789"]}
        HashMap data2 = g.fromJson("{\"id\":\"100\",\"name\":\"金苹果\",\"info\":\"种植苹果的故事\",\"page\":[\"123\",\"456\",\"789\"]}", HashMap.class);
        
        System.out.println(data2.get("page"));
        //数组部分会转成list

fastjson

使用案例

Book book = new Book("1002","唐诗三百首","诗词");
        //1 转换
        String s = JSON.toJSONString(book);
        System.out.println(s);

        //2 转回对象
        Book book1 = JSON.parseObject(s, Book.class);
        System.out.println(book1);

        //["123","456","789"]
        //3 转换数组
        List<String> data = JSON.parseArray("[\"123\",\"456\",\"789\"]", String.class);
        System.out.println(data.get(1));