android 实体对象转 json，list转 json ，map转json

1实体对象转 json

UserTable userTable=new UserTable();

userTable.setGroup(group_ss);

Gson gson=new Gson();
toast_Base(gson.toJson(userTable));

2.把jsonList转化为一个list对象
String jsonList="[{'userid':'1881140130','username':'三哥','usersex':'男','banji':'计算机1班','phone':'18255052351'},"
+ "{'userid':'1881140131','username':'蜂','usersex':'男','banji':'计算机1班','phone':'18355092351'},"
+ "{'userid':'1881140132','username':'宝','usersex':'男','banji':'计算机1班','phone':'18955072351'}]";
Gson gson1=new Gson();
List<Person> list= gson1.fromJson(jsonList, new TypeToken<List<Person>>() {}.getType());
for (Person person1 : list) {
System.out.println(person1.toString());
}

3，json转实体对象

UserTable ub = new UserTable();
Gson gson = new Gson();
ub = gson.fromJson(ja.getString(0), UserTable.class);