HashMap Demo

package com.test.collection;import java.util.HashMap;import java.util.Map;import java.util.Set;public class MapTest {public static void main(String[] args) {Map<Character, String> m = new HashMap<Character, String>();//存放元素m.put('A', "American");m.put('B', "Blundon");m.put('C',"Canada");//得到valueSystem.out.println(m.get('A'));//删除keym.remove('A');System.out.println(m);//key setSet<Character> keySet = m.keySet();System.out.println(keySet);//putAllm.putAll(m);//添加self不起作用System.out.println(m);Map<Character, String> m1 = new HashMap<Character, String>();m1.put('D', "Diga");m1.put('H', "Huhanon");m.putAll(m1);System.out.println(m);}}

American{B=Blundon, C=Canada}[B, C]{B=Blundon, C=Canada}{D=Diga, B=Blundon, C=Canada, H=Huhanon}