Map迭代

package gather;

import java.util.HashMap;
public class TestOne {

    public static void main(String[] args) {
        
        
        HashMap<String, String> map = new HashMap<String, String>();
        map.put("k1", "v1");
        map.put("k2", "v2");
        map.put("k3", "v3");
        
        
        /*
         Iterator<Entry<String, String>> iterator2 =  map.entrySet().iterator();  
         while(iterator2.hasNext()){
             Entry<String, String>entry =  iterator2.next();
             System.out.println(entry.getKey());
             System.out.println(entry.getValue());
         }
        
        Iterator<String> iterator =  map.keySet().iterator();
        while(iterator.hasNext()){
            System.out.println(iterator.next());
        }
         
         */
         
        /* 
         * 增强型for
         * for ( Entry<String, String> entry : map.entrySet()) { 
             System.out.println(entry.getKey());
             System.out.println(entry.getValue());
        }
        
         for ( String entry : map.keySet()) { 
             System.out.println(entry);
        }
        */
         
    }
    
}

 

 

 

 

http://www.trinea.cn/android/hashmap-loop-performance/