遍历Map的三种常用方法 java

import java.io.UnsupportedEncodingException;import java.util.Collection;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set;/** * @author hpjianhua * */public class TestUtils {/** * @param args * @throws UnsupportedEncodingException  */public static void main(String[] args) throws UnsupportedEncodingException {Map<String, String> map = new HashMap<String, String>();//初始化map.put("A", "米国");map.put("C", "中国");map.put("J", "日本");//第一种遍历方法: 直接遍历Map中的内容ValuesCollection values = map.values();Iterator it1 = values.iterator();while(it1.hasNext()){System.out.println(it1.next());}//第二种遍历方法: 先拿到Key的Set再根据Key去遍历ValueSet<String> set = map.keySet();Iterator it2 = set.iterator();while(it2.hasNext()){String key   = (String)it2.next();String value = (String) map.get(key);System.out.println("Key: " + key +" value: " + value);}//第三种遍历方法: 用Map的Entry对象去拿,然后再取Key 与ValueSet<Map.Entry<String, String>> setEntry = map.entrySet();Iterator<Map.Entry<String, String>> it3 = setEntry.iterator();while(it3.hasNext()){Map.Entry<String, String> entry = it3.next();System.out.println(entry.getKey() + " ___ " +entry.getValue());}}}