ObjectMapper 类处理数据转换(json字符床转集合和对象)

ObjectMapper 类处理数据转换

        Users users = new Users();
        users.setAge(1);
        users.setCountry("中国");
        users.setId(1);
        String s = JSON.toJSONString(users);
        System.out.println(s);


        //转义符一条斜杠
        Gson gson = new Gson();
        String jsonStr = gson.toJson(s);
        System.out.println(jsonStr);

        //转义符两条斜杠
        GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder.setPrettyPrinting();
        Gson gson1 = gsonBuilder.create();
        String s1 = gson1.toJson(jsonStr);
        System.out.println(s1);

        //普通JSon字符串转化 方法一
        //https://blog.csdn.net/xueyijin/article/details/124083389  还可以处理带 / 的转义字符串
        ObjectMapper objectMapper = new ObjectMapper();
        users = objectMapper.readValue(s, Users.class);


        //普通JSon字符串转化 方法二  二用的居多
        Users users1 = JSONObject.parseObject(s, Users.class);
        System.out.println(users1);

        //Json集合转集合
        List<Users> list = new ArrayList<>();
        list.add(users);
        ObjectMapper objectMapperList = new ObjectMapper();
        JavaType javaType = objectMapperList.getTypeFactory().constructParametricType(ArrayList.class, Users.class);
        list = objectMapperList.readValue(JSON.toJSONString(list), javaType);
        System.out.println("JavaType 转换为:"+list);