map里面放的list,list放的是对象,怎么遍历

Posted 2023-03-15

Map<String, List<User>> map = new HashMap<String, List<User>>();
//执行相关的添加操作
//接下来是遍历
Set<String> keys = map.keySet();
List<User> userList = null;

for(String key : keys)

userList = map.get(key);

for(User user : userList )
//执行相关的操作

参考技术A Map<String, List<User>> aa = new HashMap<String, List<User>>();

for (Iterator<String> iterator = aa.keySet().iterator(); iterator.hasNext();)
String key = iterator.next();

List<User> l = aa.get(key);

for (int i = 0; i < l.size(); i++)



参考技术B package test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class Test2
public static void main(String[] args)
User user1 = new User();
user1.setName("xiaosong");
user1.setSex("男");
user1.setAge(24);
User user2 = new User();
user2.setName("xiaotang");
user2.setSex("男");
user2.setAge(26);
Map<String,List<User>> map = new HashMap<String,List<User>>();
List<User> list = new ArrayList<User>();
list.add(user1);
list.add(user2);
map.put("1", list);
map.put("2", list);
//Collection<String,List<User>> c = map<String,List<User>>.values();
Set<String> keys = map.keySet(); //获取所有的key值
//List<User> userList = null;

for(String key: keys)
System.out.println(key);

for(User user:list)
System.out.println(user.getAge() + user.getName()+ user.getSex() );



在包里定义一个 User 类 里面定义 name age sex 然后 有set get 方法。