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:774346810@qq.com
  * @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());
         }
     }
 }