编写Java程序，使用List集合和Map集合输出 市和区

如图：

代码：

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;

public class Test1 {
		public static void main(String[] args) {
			//云南省的 - 市
			ArrayList<String> ynCity = new ArrayList<>();
			ynCity.add("昆明市");
			ynCity.add("昭通市");
			ynCity.add("大理市");
			ynCity.add("丽江市");
			//湖南省的 - 市
			ArrayList<String> hnCity = new ArrayList<>();
			hnCity.add("长沙市");
			hnCity.add("岳阳市");
			hnCity.add("常德市");
			hnCity.add("永州市");
			//将市 和 区 存入Map集合
			HashMap<String, ArrayList<String>> provinceCity = new HashMap<String, ArrayList<String>>();
			provinceCity.put("云南省",ynCity);
			provinceCity.put("湖南省",hnCity);
			//将省和市存入countries Map集合中
			HashMap<String, HashMap<String,ArrayList<String>>> countries = new HashMap<String,HashMap<String,ArrayList<String>>>();
			countries.put("中国",provinceCity);
//			countries.put("美国",provinceCity);//这里只写了中国的省和市这行注释掉

			Set<String> countriesMapkey = countries.keySet();//得到Map 集合 countries的键 存入countriesMapkey中
			Iterator it1 = countriesMapkey.iterator();//用键创建一个迭代器
			while (it1.hasNext()) {
				Object countriesMapkeys = it1.next();//遍历得到键集合存入countriesMapkeys
				System.out.println(countriesMapkeys);
				HashMap<String, ArrayList<String>> countriesMapValue = countries.get(countriesMapkeys);//得到键集合对应的值存入countriesMapValue
				Set<String> provinceCityMapKey = countriesMapValue.keySet();//得到Map集合中provinceCity的键

				Iterator it2 =  provinceCityMapKey.iterator();//创建一个迭代器
				while (it2.hasNext()) {
					Object provinceCityMapKeys = it2.next();//得到Map 集合 provinceCity的键 存入countriesMapkey中
					System.out.println("    "+provinceCityMapKeys);
					ArrayList<String> provinceCityValue = provinceCity.get(provinceCityMapKeys);//得到provinceCity的键对应的值集合
					for (int i = 0; i < provinceCityValue.size(); i++) {
						System.out.println("        "+provinceCityValue.get(i));//循环输出provinceCity的值
					}
				}
			}

		}
}