去除map中鍵爲偶數的元素

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
public class TestMap {
	public static void main(String[] args) {
		HashMap<Integer,String> hm=new HashMap<Integer,String>();
		hm.put(1, "星期一");
		hm.put(2, "星期二");
		hm.put(3, "星期三");
		hm.put(4, "星期四");
		hm.put(5, "星期五");
		hm.put(6, "星期六");
		hm.put(7, "星期七");
		/*下面註釋的方法會報錯,報錯原因以後詳細分析*/
		/*for(Map.Entry<Integer, String> entry:hm.entrySet()){
			Integer temp=entry.getKey();
			if(temp%2==0){
				hm.remove(1);
			}
		}*/
		Iterator<Map.Entry<Integer, String>> it = hm.entrySet().iterator();
		while(it.hasNext()){
			Map.Entry<Integer, String> entry = it.next();
            Integer key = entry.getKey();
            if(key%2==0){
            	it.remove();
            }
		}
		for(Map.Entry<Integer, String> entry:hm.entrySet()){
			System.out.println(entry.getKey());
		}
	}
}

運行結果

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