提交作业，不足之处请大家指正

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class Start {
   CaiPan cp;
   List<Pai> pailist,pailist2;
   public Start(){
       cp=new CaiPan();
       System.out.println("----------创建扑克牌----------");
       cp.getpai();
       System.out.println("\n----------开始洗牌----------");
       pailist=cp.xipai();
       System.out.println("----------创建玩家----------");
       System.out.println("请输入第一位玩家的ID和姓名：");
       WanJia wj1=new WanJia();
       System.out.println("请输入第二位玩家的ID和姓名：");
       WanJia wj2=new WanJia();
       System.out.println("-----欢迎玩家："+wj1.name);
       System.out.println("-----欢迎玩家："+wj2.name);
       System.out.println("----------开始发牌----------");
       System.out.println("-----玩家"+wj1.name+"拿牌...");
       wj1.getPai(pailist);
       System.out.println("-----玩家"+wj2.name+"拿牌...");
       wj2.getPai(pailist);
       System.out.println("-----玩家"+wj1.name+"拿牌...");
       wj1.getPai(pailist);
       System.out.println("-----玩家"+wj2.name+"拿牌...");
       wj2.getPai(pailist);
       System.out.println("----------发牌结束----------\n----------开始游戏----------");
       Collections.sort(wj1.shoupai);
       System.out.println("玩家"+wj1.name+"最大的手牌为："+wj1.shoupai.get(1).name);
       Collections.sort(wj2.shoupai);
       System.out.println("玩家"+wj2.name+"最大的手牌为："+wj2.shoupai.get(1).name);
       pailist2=new ArrayList<Pai>();
       pailist2.add(wj1.shoupai.get(1));
       pailist2.add(wj2.shoupai.get(1));
       cp.bipai(pailist2,wj1,wj2);
       System.out.print("玩家1的手牌为:");
       for (Pai pai : wj1.shoupai) {
           System.out.print(pai.name+"、");
       }
       System.out.print("\n玩家2的手牌为:");
       for (Pai pai : wj2.shoupai) {
           System.out.print(pai.name+"、");
       }
   }
   public static void main(String[] args) {
       Start st=new Start();
   }
}

//------------------------------------------------------------------------------------------------------------------------

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.Collections;
import java.util.Map.Entry;

public class CaiPan {
   Map<Integer,Pai> paimap;
   List<Pai> pailist;
   Random sjs;

   public CaiPan(){
       paimap=new HashMap<Integer,Pai>();
       pailist=new ArrayList<Pai>();
       sjs=new Random();
   }
   public void getpai(){
       Integer key=0;
       Pai pai;
       String[] nums={"2","3","4","5","6","7","8","9","10","J","Q","K","A"};
       String[] huas={"红桃","黑桃","梅花","方块"};
       for(int i=0;i<13;i++){
           for(int j=3;j>=0;j--){
               pai=new Pai(nums[i],huas[j]);
               pai.daxiao=key;
               paimap.put(key, pai);
               key++;
           }
       }
       System.out.print("----------扑克牌创建成功----------\n为：[");
       for (int i=0;i<paimap.size();i++) {
           System.out.print(paimap.get(i).name+"、");
       }
       System.out.print("]");
   }
   public List<Pai> xipai(){
       Set<Entry<Integer,Pai>> jianzhi=paimap.entrySet();
       for (Entry<Integer,Pai> entry: jianzhi) {
           pailist.add(entry.getValue());
       }
       for(int i=0;i<pailist.size();i++){
           pailist.add(sjs.nextInt(pailist.size()),pailist.get(0));
           pailist.remove(0);
       }
       System.out.println("----------洗牌结束！----------");
       return pailist;
   }
   public void bipai(List<Pai> pailist2,WanJia wj1,WanJia wj2){
       Collections.sort(pailist2);
       if(wj1.shoupai.contains(pailist2.get(1))){
           System.out.println("玩家"+wj1.name+"获胜！");
       }else{
           System.out.println("玩家"+wj2.name+"获胜！");
       }
   }
}

//-----------------------------------------------------------------------------------------------------------------------

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class WanJia {
   int id;
   String name;
   List<Pai> shoupai;
   Scanner sc;
   public WanJia(){
       shoupai=new ArrayList<Pai>();
       sc=new Scanner(System.in);

       while(true){
           System.out.println("请输入ID：");
           try{
               this.id=sc.nextInt();
           }catch(Exception e){
               System.out.println("ID无效，请重新输入！");
               String s=sc.next();    //把scanner中的数据吐掉，不然会一直循环
               continue;
           }
           break;
       }
       System.out.println("请输入姓名：");
       this.name=sc.next();
   }
   public void getPai(List<Pai> pailist){
       Pai pai=pailist.get(0);
       this.shoupai.add(pai);
       pailist.remove(0);
   }
}

//---------------------------------------------------------------------------------------------------------------

public class Pai implements Comparable<Pai>{
   public String name;
   public String number;
   public String hua;
   public Integer daxiao;
   public Pai(String num,String hua){
       this.number=num;
       this.hua=hua;
       this.name=hua+num;
   }
   public int compareTo(Pai pai){
       return this.daxiao.compareTo(pai.daxiao);
   }
}