遍历map的几种方式

package com.chili.test;

import java.util.HashMap;

import java.util.Iterator;

import java.util.Map;

/*

* 遍历Map的几种方式

* @author sunset

*/

public class TraversalMap {

public static void main(String[] args)

{

//测试

Map<String, String> map1 = new HashMap<String, String>();

map1.put("key1", "val1");

map1.put("key2", "val2");

map1.put("key3", "val3");

traversalMapForKeySet(map1);

traversalMapByIterator(map1);

traversalMapByEntrySet(map1);

traversalMapByValues(map1);

}

/*

* 遍历Map方式一：通过Map.keySet遍历key和value

* 入参：Map<String, String> map

*/

private static void traversalMapForKeySet(Map<String, String> map)

{

for(String key : map.keySet())

{

System.out.println(key+"=======>"+map.get(key));

}

}

/*

* 遍历Map的方式二：通过Iterator以及map.entrySet()

* 入参：Map<String, String> map

*/

private static void traversalMapByIterator(Map<String, String> map)

{

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

while(it.hasNext())

{

Map.Entry<String, String> entry = it.next();

System.out.println(entry.getKey()+">>>"+entry.getValue());

}

}

/*

* 遍历Map的方式三：通过Map.entrySet遍历key和value 推荐使用

* 入参：Map<String, String> map

*/

private static void traversalMapByEntrySet(Map<String, String> map)

{

for(Map.Entry<String, String> entry : map.entrySet())

{

System.out.println(entry.getKey()+"~~~~~~~~~~>>"+entry.getValue());

}

}

/*

* 遍历Map的方式四：通过Map.values()遍历所有的value

* 注意：此方式不能遍历key

* 入参：Map<String, String> map

*/

private static void traversalMapByValues(Map<String, String> map)

{

for(String val : map.values())

{

System.out.println(val);

}

}

}