java 遍历map时删除元素

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import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

public class TestMap {

/* 在遍历Map过程中,不能用map.put(key,value),map.remove(key)来修改和删除元素，会引发并发修改异常*/

   public static void main(String[] args) {
       HashMap<String, String> testMap = new HashMap<String,String>();
       testMap.put("1","test1");
       testMap.put("2","test2");
       testMap.put("2","test2");
       testMap.put("2","test2");
       testMap.put("3","test3");
       testMap.put("4","test4");
       testMap.put("4","test4");
       testMap.put("4","test4");

       Set mapSet = testMap.entrySet();
       Iterator iterator = mapSet.iterator();
       while(iterator.hasNext())
       {
           Map.Entry mapEntry = (Map.Entry) iterator.next();

           String key = mapEntry.getKey().toString();
           String value = mapEntry.getValue().toString();

           System.out.printf("key: %s value:%s\r\n", key, value);
       }

          System.out.printf("***************deleting************\r\n");

          Iterator<Map.Entry<String, String>> it = testMap.entrySet().iterator();
          while(it.hasNext())
          {
              Map.Entry<String,String> entry = it.next();
              String key = entry.getKey();
              int k = Integer.parseInt(key);
              if(k%2==1)
              {
                  System.out.printf("delete key:%s value:%s\r\n", key, entry.getValue());
                  it.remove();
              }
          }

          System.out.printf("*****************result***********\r\n");


          iterator = mapSet.iterator();

          while(iterator.hasNext())
          {
              Map.Entry mapEntry = (Map.Entry)iterator.next();
              String key = mapEntry.getKey().toString();
              String value = mapEntry.getValue().toString();

              System.out.printf("key:%s value:%s\r\n", key,value);

          }
   }
}

出自http://www.dedecms.com/knowledge/program/jsp-java/2012/0810/4490.html