遍历map集合的三种方式

首先创建map集合

//创建

HashMap<String,User> userMap=new HashMap<String,User>();

//put方法赋值

userMap.put("james",new User("james","111"));

userMap.put("kobe",new User("kobe","123"));

1、迭代器遍历,根据key

Set<String> keySet=userMap.KeySet();

Iterator<String> iterator=keySet.iterator();

while(iterator.hasnext()){

    String key=iterator.next();

    System.out.println("key="+key+",value="+userMap.get(key));

}

2、根据entrySet遍历

Set<Map.Entry<String,User>> entries=userMap.entrySet();

for(Map.Entry<String,User> entry:entries){

    System.out.println("key:"+entry.getKey()+",value:"+entry.getValue());

}

3、直接遍历value

Collection<User> values=userMap.values();

for(User value:values){

    System.out.println(value);

}