HashMap遍历的几种方法
写一下HashMap遍历的几种方法,以后自己使用方便
public static void main(String[] args) {
HashMap<String, Integer> hashMap = new HashMap<String, Integer>();
hashMap.put("a", 1);
hashMap.put("b", 2);
hashMap.put("c", 2);
Integer getValue = hashMap.get("a");
System.out.println(getValue);
//迭代器遍历
System.out.println("======keySet遍历======");
Iterator<String> iteratorMap1 = hashMap.keySet().iterator();
while (iteratorMap1.hasNext()) {
String key = iteratorMap1.next();
Integer value = hashMap.get(key);
System.out.println(key+"="+value);
}
System.out.println("======entrySet遍历======");
Iterator<Entry<String, Integer>> iteratorMap2 = hashMap.entrySet().iterator();
while (iteratorMap2.hasNext()) {
Entry<String, Integer> nextMap = iteratorMap2.next();
String key = nextMap.getKey();
Integer value = nextMap.getValue();
System.out.println(key+"="+value);
}
//增强for循环
System.out.println("======增强for循环keySet遍历======");
for(String key : hashMap.keySet()) {
System.out.println(key+"="+hashMap.get(key));
}
System.out.println("======增强for循环entrySet遍历======");
for(Entry<String, Integer> entry : hashMap.entrySet()) {
System.out.println(entry.getKey()+"="+entry.getValue());
}
}