for(Map.Entry<String, String> entry: params.entrySet()) {
            String key = entry.getKey();
            String value = entry.getValue();
}

   Iterator<Entry<UserEntity, Long>> iter = countTaskOfUserMap.entrySet().iterator();      
       while(iter.hasNext()){      
          Map.Entry entry = (Map.Entry)iter.next();      
          UserEntity key = (UserEntity)entry.getKey();      
          long value = (Long)entry.getValue();      
   }      

 1 mport java.util.HashMap;  
 2 import java.util.Iterator;  
 3 import java.util.Map;  
 4   
 5 public class HashMapTest {  
 6    private static Map<Integer, String> map=new HashMap<Integer,String>();  
 7       
 8    /**  1.HashMap 类映射不保证顺序；某些映射可明确保证其顺序: TreeMap 类 
 9     *   2.在遍历Map过程中,不能用map.put(key,newVal),map.remove(key)来修改和删除元素， 
10     *   会引发 并发修改异常,可以通过迭代器的remove()： 
11     *   从迭代器指向的 collection 中移除当前迭代元素 
12     *   来达到删除访问中的元素的目的。   
13     *   */   
14    public static void main(String[] args) {  
15         map.put(1,"one");  
16         map.put(2,"two");  
17         map.put(3,"three");  
18         map.put(4,"four");  
19         map.put(5,"five");  
20         map.put(6,"six");  
21         map.put(7,"seven");  
22         map.put(8,"eight");  
23         map.put(5,"five");  
24         map.put(9,"nine");  
25         map.put(10,"ten");  
26         Iterator<Map.Entry<Integer, String>> it = map.entrySet().iterator();  
27         while(it.hasNext()){  
28             Map.Entry<Integer, String> entry=it.next();  
29             int key=entry.getKey();  
30             if(key%2==1){  
31                 System.out.println("delete this: "+key+" = "+key);  
32                 //map.put(key, "奇数");   //ConcurrentModificationException  
33                 //map.remove(key);      //ConcurrentModificationException  
34                 it.remove();        //OK   
35             }  
36         }  
37         //遍历当前的map；这种新的for循环无法修改map内容，因为不通过迭代器。  
38         System.out.println("-------\n\t最终的map的元素遍历：");  
39         for(Map.Entry<Integer, String> entry:map.entrySet()){  
40             int k=entry.getKey();  
41             String v=entry.getValue();  
42             System.out.println(k+" = "+v);  
43         }  
44     }  
45 }