阿里巴巴-蒲公英云

阿里巴巴

FastJSON

引入依赖或者Jar包

com.alibaba
fastjson
1.1.23

将Map转成JSON

Map map = new HashMap();

    map.put("key1", "value1");
    map.put("key2", "value2");
    String mapJson = JSON.toJSONString(map);
    System.out.println(mapJson);
    //输出{"key1":"value1","key2":"value2"}
    //TODO 泛型的反序列化（使用TypeReference传入类型信息）
    Map<String, Object> map2 = JSON.parseObject(mapJson, new TypeReference<Map<String, Object>>(){ });
    System.out.println(map2);

将List<Map转成JSON

List> list = new ArrayList>();

    Map<String, Object> map1 = new HashMap<String, Object>();
    map1.put("key1", "value1");
    map1.put("key2", "value2");
    Map<String, Object> map2 = new HashMap<String, Object>();
    map2.put("key1", "value3");
    map2.put("key2", "value4");
    list.add(map1);
    list.add(map2);
    String jsonstr = JSON.toJSONString(list);
    System.out.println(jsonstr);
    System.out.println("==========================================");
    //输出 [{"key1":"value1","key2":"value2"},{"key1":"value3","key2":"value4"}]
    // TODO String objJson = JSON.toJSONString(Object object, boolean prettyFormat)
    //TODO 传入一个对象和一个布尔类型（是否格式化），将对象转成格式化后的JSON字符串。
    String listJson1 = JSONArray.toJSONString(list, true);
    System.out.println(listJson1);
    System.out.println("==========================================");
    String listJson2 = JSONArray.toJSONString(list, false);
    System.out.println(listJson2);
    System.out.println("==========================================");
    //TODO 使用单引号
    String listJson = JSON.toJSONString(list, SerializerFeature.UseSingleQuotes);
    //输出 [{'key1':'value1','key2':'value2'},{'key1':'value3','key2':'value4'}]
    System.out.println(listJson);
    System.out.println("==========================================");
    //TODO 集合反序列化
    List<Map> list1 = JSON.parseArray(listJson, Map.class);
    for(Map<String, Object> map : list1){ 
        System.out.println(map.get("key1"));
        System.out.println(map.get("key2"));
    }
    //输出 value1 value2 value3 value4

Java bean

UserDO userDO = new UserDO();

    userDO.setId(1);
    userDO.setName("乐乐");
    userDO.setAge(12);
    String userJson = JSON.toJSONString(userDO);
    System.out.println(userJson);
    //输出 {"age":12,"id":1,"username":"乐乐"}
    //TODO 普通序列化
    UserDO user1 = (UserDO) JSON.parse(userJson);
    System.out.println(user1.getAge());
    //输出 12
    //TODO 指定Class信息反序列化
    UserDO user2 = JSON.parseObject(userJson,UserDO.class);
    System.out.println(user2.getName());
    //输出 乐乐

时间

//TODO （1）FastJSON将java.util.Date转成long。

    String dateJson1 = JSON.toJSONString(new Date());
    System.out.println(dateJson1);
    System.out.println("==========================================");
    //输出 1547900848449
    //TODO（2）使用SerializerFeature特性格式化日期。
    String dateJson2 = JSON.toJSONString(new Date(), SerializerFeature.WriteDateUseDateFormat);
    System.out.println(dateJson2);
    System.out.println("==========================================");
    //输出 "2019-01-19 20:29:24"
    //TODO（3）指定输出日期格式
    String dateJson3 = JSON.toJSONStringWithDateFormat(new Date(), "yyyy-MM-dd HHss");
    System.out.println(dateJson3);
    System.out.println("==========================================");
    //输出"2019-01-19 20:32:34"