遍历Map集合的几种方式

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.Map;

 import java.util.Map.Entry;

 /**

  * <p>遍历Map集合</p>

  * @author:[email protected]

  * @date:2017-5-30

  */

 public class Test {

     public static void main(String[] args) {

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

         map.put("username", "yujiwei");

         map.put("password", "12345");

         map.put("address", "hangzhou");

         map.put("love", "编程");

         //1.获取所有的key

         for(String key : map.keySet()){//返回的是map的key值

             String value = map.get(key);//通过key取value

             System.out.println("key = " + key + ",value = " + value);

         }

         System.out.println("----------------------------------");

         //2.通过map.entrySet的iterator来遍历Map集合

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

         while(it.hasNext()){

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

             System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());

         }

         System.out.println("----------------------------------");

         //3.通过Map.Entry来遍历Map集合

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

             System.out.println("key= " + entry.getKey() + " and value= "+ entry.getValue());

         }

     }

 }