JSON在Java中的转换

//java bean的三大条件：1.私有化的属性 2.公共的get/set方法 3.一个无参构造器

//1.将javaBean对象转换成json格式的字符串

User user = new User("zhangsan",20);
String useStr = JSON.toJSONString(user);
System.out.println(useStr);


//2.将 json格式的字符串转换成javaBean对象
String jsonStr = "{ "name" : "lisi" , "age" : 25 }";
User user01 = JSON.parseObject(jsonStr,User.class);
System.out.println(user01.getName());
System.out.println(user01.getAge());

//3.将 json格式的字符串（数组）转换成java中的List
String userList = "[{ "name" : "wangwu" , "age" : 23 },{ "name" : "zhaoliu" , "age" : 20 }]";
List<User> list = JSON.parseArray(userList, User.class);
System.out.println(list.size());
System.out.println(list.get(1).getName());
System.out.println(list.get(0).getAge());

//4.将List转化为json格式的字符串
List<User> list2 = new ArrayList();
list2.add(new User("qianyi", 26));
list2.add(new User("suner", 23));
list2.add(new User("zhangsan", 25));
list2.add(new User("lisi", 24));
String str2 = JSON.toJSONString(list2);
System.out.println(str2);