package com.crossoverjie.basic; import java.security.Key; import java.util.HashMap; import java.util.Iterator; import java.util.Map; /** * Function: * * @author crossoverJie * Date: 05/05/2018 12:42 * @since JDK 1.8 */ public class HashMapTest { public static void main(String[] args) { Map map = new HashMap<>(16); map.put("1", 1); map.put("2", 2); map.put("3", 3); map.put("4", 4); Iterator> entryIterator = map.entrySet().iterator(); while (entryIterator.hasNext()) { Map.Entry next = entryIterator.next(); System.out.println("key=" + next.getKey() + " value=" + next.getValue()); } System.out.println("============="); Iterator iterator = map.keySet().iterator(); while (iterator.hasNext()){ String key = iterator.next(); System.out.println("key=" + key + " value=" + map.get(key)); } System.out.println("============="); map.forEach((key, value) -> { System.out.println("key=" + key + " value=" + map.get(key)); }); } }