1.hashmap.keySet(),此法可得key和value;
2.Map.Entry<x,x> entry ; foreach遍历 hashmap.entrySet();
3.对第2种创建遍历器 Iterator <Map.Entry<x, x>> it , 遍历it.hasNext();
4.hashmap.values() 不好用,只能得value。
public static void main(String[] args) {
HashMap<Integer, String> hashmap = new HashMap<>();
hashmap.put(1,"gogo");
hashmap.put(2,"wade");
hashmap.put(3,"james");
hashmap.put(4,"curry");
// 1. 通过Map.keySet遍历key和value:
for (int key : hashmap.keySet()){
System.out.println("key: "+ key + "; value: " + hashmap.get(key));
}
//2. 通过Map.entrySet使用iterator遍历key和value:
Iterator<Map.Entry<Integer, String>> it = hashmap.entrySet().iterator();
while (it.hasNext()){
Map.Entry<Integer, String> entry = it.next();
System.out.println("key: "+ entry.getKey() + "; value: " + entry.getValue());
}
//3. 通过Map.entrySet遍历key和value
for(Map.Entry<Integer, String> entry : hashmap.entrySet()){
System.out.println("key: "+ entry.getKey() + "; value: " + entry.getValue());
}
//4. 通过Map.values()遍历所有的value,但不能遍历key
for (String value : hashmap.values()) {
System.out.println("value: "+value);
}
}