【JAVA】List和map的简单示例代码

package com.app.listmap;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;

public class Classes {
/**
* 1.List、Map中讲到方法调用
* 2.创建班级的List列表并打印
* 3.创建班级集合，且能够区分一班、二班，并打印每个班级的人员信息。
* @param name
*/
List<String> Members;
Classes(String name){
//用来随机产生班级人数。
Random r = new Random();
Members = new ArrayList<String>();
for (int i=0;i<r.nextInt(20);i++) {
Members.add(name+" "+i+"号");
}
System.out.println(name+"班级成员名单：");
for(int i = 0; i<Members.size();i++){
System.out.print(Members.get(i)+"     ");
}
}

public static void main(String[] args) {
Classes One = new Classes("大白兔");
System.out.println();
Classes Two = new Classes("小灰狼");
Map<Integer, List<String>> Record = new HashMap<Integer, List<String>>();
Record.put(1, One.Members);
Record.put(2, Two.Members);

System.out.println('\n'+"下面开始遍历班级集合：");
System.out.println("序 列 号            "+"成 员 名");
for(Map.Entry<Integer, List<String>> map: Record.entrySet()){
System.out.print(map.getKey()+"班             ");
System.out.println(map.getValue());
}

System.out.println("遍历key:");
for (Integer i: Record.keySet()){
//遍历出key用i,遍历出value用get(i)
Record.get(i);
System.out.print(Record.get(i)+"班             ");
}
Record.remove(1);
System.out.println('\n'+"Remove之后");
for(Map.Entry<Integer, List<String>> map: Record.entrySet()){
System.out.print(map.getKey()+"班             ");
System.out.println(map.getValue());
}
}
}