一.HashSet的遍历

1.foreach遍历

Set<String> set = new HashSet<String>();
set.add("a");
set.add("b");
set.add("c");
for (String s:set) 
{
			System.out.println(s);
}

2.通过迭代器遍历

Set<String> set = new HashSet<String>();
set.add("a");
set.add("b");
set.add("c");
Iterator<String> iterator = set.iterator();
while(iterator.hasNext())
{
	System.out.print(iterator.next()+" ");
}

二.HashMap的遍历

1.entry进行遍历

Map<String, Integer> map = new HashMap<String, Integer>();
		map.put("1", 1);
		map.put("2", 2);
        map.put("3", 3);
		for (Map.Entry<String, Integer> entry : map.entrySet()) {
			System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
		}

2.foreach分别对key和value遍历

Map<String, Integer> map = new HashMap<String, Integer>();
		map.put("1", 1);
		map.put("2", 2);
        map.put("3", 3);
// key
		for (String key : map.keySet()) {
			System.out.println("Key = " + key);
            
            System.out.println("value is "+ map.get(key));//通过key取出value
		}
 
		// value
		for (Integer value : map.values()) {
			System.out.println("Value = " + value);
		}

3.迭代器进行遍历

Map<String, Integer> map = new HashMap<String, Integer>();
		map.put("1", 1);
		map.put("2", 2);
        map.put("3", 3);
Iterator<Map.Entry<String, Integer>> iterator = map.entrySet().iterator();
		while (iterator.hasNext()) {
			Map.Entry<String, Integer> entry = iterator.next();
			System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
		}