关于Map集合的遍历总结

转：http://www.cnblogs.com/lsgspace/p/4666020.html

以下是遍历Map集合的几种方式：

public static void main(String[] args)
{
Map<String, String> map = new HashMap<String, String>();
map.put("1", "张三");
map.put("2", "李四");
map.put("3", "王五");

//调用
}

　　

1、通过Map.keySet遍历key和value

private static void findKey(Map<String, String> map)
{
System.out.println("findKey");

for (String key : map.keySet())
{
System.out.println("key = " + key);
System.out.println("value = " + map.get(key));
}
}

2、通过Map.values遍历value

private static void findValue(Map<String, String> map)
{
System.out.println("findValue");

for (String value : map.values())
{
System.out.println("value = " + value);
}
}

3、通过Map.entrySet和迭代器遍历Map

private static void findIterator(Map<String, String> map)
{
System.out.println("findIterator");

Iterator<Map.Entry<String, String>> carIterator = map.entrySet()
.iterator();

while (carIterator.hasNext())
{
Map.Entry<String, String> entry = carIterator.next();
System.out.println("key = " + entry.getKey());
System.out.println("value = " + entry.getValue());
}
}

4、Map.entrySet加for in 循环（推荐）

private static void findEntrySet(Map<String, String> map)
{
System.out.println("findEntrySet");

for (Entry<String, String> entry : map.entrySet())
{
System.out.println("key = " + entry.getKey());
System.out.println("value = " + entry.getValue());
}
}