添加你喜欢的歌手以及你喜欢他唱过的歌曲，并遍历
package Test0726;import java.util.ArrayList;
import java.util.HashMap;
import java.util.*;public class SingerTest {public static void main(String[] args) {HashMap singers = new HashMap();String singer1 = "周杰伦";//添加一个歌手和歌曲ArrayList songs1 = new ArrayList();songs1.add("夜曲");songs1.add("晴天");songs1.add("七里香");songs1.add("发如雪");songs1.add("屋顶");songs1.add("青花瓷");singers.put(singer1, songs1);//再添加1个歌手和歌曲String singer2 = "林俊杰";ArrayList songs2 = new ArrayList<>();songs2.add("江南");songs2.add("曹操");songs2.add("小酒窝");songs2.add("可惜没如果");singers.put(singer2, songs2);Set entrySet = singers.entrySet();Iterator iterator = entrySet.iterator();while(iterator.hasNext()){Map.Entry entry = (Map.Entry) iterator.next();System.out.println("歌手：" + entry.getKey());System.out.println("歌曲有：" + entry.getValue());}}
}
//1获取Map，并遍历MAP中的所有的Key
/2根据提示，从键盘获取省份值，判断此省份是否存在，如果存在遍历其value 中的各个城市。 //如果不存在，提示用户重新输入
//3. 根据提示，从键盘获取城市，遍历各个城市构成的String[],判断输入的城市是否存在于此数组中 // 如果存在，信息登记完毕。如果不存在，提示用户重新输入。
package Test0726;import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;public class CityMap {public static void main(String[] args) {//1获取Map，并遍历MAP中的所有的KeyMap map = CityMapTest.model;Set provinces = map.keySet();for (Object province : provinces) {System.out.print(province + "\t\t");}System.out.println();//2根据提示，从键盘获取省份值，判断此省份是否存在，如果存在遍历其value 中的各个城市。//如果不存在，提示用户重新输入Scanner scan = new Scanner(System.in);String[] cities;while (true) {System.out.println("请选择你所在的省份：");String provtainsKey = scan.next();//获取省份对应的各个城市构成的String[]cities = (String[]) map.get(provtainsKey);if (cities == null) {System.out.println("你输入的省份有误，请重新输入");} else {break;//用户输入省份存在}}for (int i = 0; i < cities.length; i++) {System.out.print(cities[i] + "\t\t");}//3. 根据提示，从键盘获取城市，遍历各个城市构成的String[],判断输入的城市是否存在于此数组中// 如果存在，信息登记完毕。如果不存在，提示用户重新输入。l:while(true){System.out.println("\n请输入你所在的城市：");String city = scan.next();for (int i= 0; i< cities.length;i++){if(city.equals(cities[i])){System.out.println("信息登记完毕");break l;}}System.out.println("你输入的信息有误");}scan.close();}
}class CityMapTest{public static Map model = new HashMap();static{model.put("北京",new String[] {"北京"});model.put("辽宁",new String[] {"沈阳","盘锦","铁岭","丹东","大连","锦州","营口"});model.put("吉林",new String[] {"长春","延边","吉林","白山","白城","四平","松原"});model.put("河北",new String[] {"承德","沧州","邯郸","邢台","唐山","保定","石家庄"});model.put("河南",new String[] {"郑州","许昌","开封","洛阳","商丘","南阳","新乡"});model.put("山东",new String[] {"济南","青岛","日照","临沂","秦安","聊城","德州"});}
}
