java集合遍历方法

for

List<Integer> list = new ArrayList();
		for (int i = 0; i < list.size(); i++) {
			Integer num = list.get(i);
			System.out.println(num);
		}

iterator

Set<Integer> set = new HashSet<>();
		set.add(4);
		
		Iterator<Integer> it = set.iterator();
		while(it.hasNext()){
			Integer num = it.next();
			System.out.println(num);
		}


Map<String, Integer> people = new HashMap<>(){
			{
				put("tom", 19);
				put("lily", 18);
			}
		};
		
		Iterator<Integer> it = people.keySet().iterator();
		while(it.hasNext()){
			String key = it.next();
			Integer value = people.get(key);
			System.out.println(key + "," + value);
		}

增强for

 for (String s : listNames) {
            System.out.println(s);
        }