遍历Map

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一、创建Map

//创建一个key为String，value为User对象的MapMap<String,User> users = new HashMap<String,User>();User user1=new User("1","1111","123456");User user2=new User("2","2222","12345678");User user3=new User("3","3333","12345612");users.put("1",user1);users.put("2",user2);users.put("3",user3);

二、遍历Map

//1.根据values()获得一个map中value值的集合for(User user:users.values()){System.out.println(user.getUserName());}//2.根据keySet()获得一个map中key值的集合for(String key:users.keySet()){System.out.println(users.get(key).getUserName());}//3.map本身不能获得迭代器，先转entrySet再获得IteraorIterator<Map.Entry<String, User>> it = users.entrySet().iterator();while(it.hasNext()){Map.Entry<String,User> entry = it.next();System.out.println(entry.getValue().getUserName());}//4.将map转成entrySet直接遍历for(Map.Entry<String, User> entry:users.entrySet()){System.out.println(entry.getValue().getUserName());}

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