package com.xhx.collection;import org.junit.Test;import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;/*** xuhaixing* 2018/7/15 19:59**/
public class TestHashMapApp {/*** 循环的几种方式*/@Testpublic void testHashMap1(){Map<String,String> map = new HashMap<String, String>();map.put("a","aaa");map.put("b","bbb");map.put("c","ccc");map.put("d","ddd");//通过key    Set<T> key = map.keySet()for(String key:map.keySet()){System.out.println("key="+key+" value="+map.get(key));}//key和value都循环for(Map.Entry<String,String> entry : map.entrySet()){System.out.println("key="+entry.getKey()+" value="+entry.getValue());}//通过迭代器Iterator<Map.Entry<String, String>> iterator = map.entrySet().iterator();while (iterator.hasNext()){Map.Entry<String, String> entry = iterator.next();System.out.println("key="+entry.getKey()+" value="+entry.getValue());}//只循环valuefor(String value : map.values()){System.out.println("value="+value);}}
}

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