Java之集合常见例题（1、统计字符出现次数2、集合嵌套遍历。3、斗地主）

一、统计字符串中字符出现的次数（数字、字母、汉字都可以）

package com.westos.GuessNumber;

import java.util.Scanner;

/** * 猜数字：随机生成1-100之间的数字。由用户输入值进行比对，返回猜测的次数 * 不足：无法完成连续多次持续玩游戏。 * @author 大虾 * */
public class GuessNumber {
   

    public static int getRandom (int start,int end) {
        return (int) (Math.random()*(end-start)+start);

    }
    public void guessNumber() {
        System.out.println("============猜数字游戏开始=========\n");
        System.out.println("请输入1-100之间的数字");
        int random = getRandom(1, 100);
        int count = 0;
        while(true) {
            Scanner sc = new Scanner(System.in);
            String str = sc.next();
            Integer num = Integer.parseInt(str);
            if(num == 0) {
                System.out.println("再玩一次！");
                guessNumber();
                break;
            }
            if(num == -1) {
                System.out.println("游戏结束，再见！");
                System.exit(0);
            }
            if(num > random) {
                System.out.println("您输入的值" + num + "大了" );
                count++;
            }
            if(num < random) {
                System.out.println("您输入的值" + num + "小了");
                count++;
            }
            if(num == random) {
                count++;
                System.out.println("Congratulations!经过"+ count + "次, 您猜对了");
                System.out.println("======Continue? 0继续/-1退出=========\n");
                continue;
            }   
    }
    }
    public static void main(String[] args) {
                GuessNumber gn = new GuessNumber();
                gn.guessNumber();

                }
    }

二、集合的嵌套遍历（万剑不离其宗，只举一个例子）

package org.wests.HomeWork03;

import java.util.HashMap;

/** * 集合的嵌套 * A:案例演示 集合嵌套之HashMap嵌套HashMap 网星软件 jc 基础班 张三 20 李四 22 jy 就业班 王五 21 赵六 23 * @author 代虎 * */
public class HomeWork01 {
   

    public static void main(String[] args) {
        HashMap<String,HashMap<String,Integer>> map = new HashMap<String, HashMap<String,Integer>>();

        HashMap<String, Integer> hashMap01 = new HashMap<String,Integer>();
        hashMap01.put("张三", 20);
        hashMap01.put("李四", 22);

        HashMap<String, Integer> hashMap02 = new HashMap<String,Integer>();
        hashMap02.put("王五", 21);
        hashMap02.put("赵六", 23);

        map.put("基础班", hashMap01);
        map.put("就业班", hashMap02);

        for(String str:map.keySet()) {
            System.out.println(str);
            for(String str01:map.get(str).keySet()) {
                System.out.println("\t" + str01 + map.get(str).get(str01));
            }
        }

    }

}

三、编写程序完成斗地主模式

package com.westos.chinesePoker;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;

/** *加强版的斗地主 EnhancedVersion *在version1.0的基础上加入扑克排序. * @author 大虾 * @version 2.0 */
public class ChinesePokerEnhanced {

    public static void main(String[] args) {
        //0-53代表每个对应的扑克
        Map<Integer, String> map = new HashMap<Integer,String>();
        List<String> list = new ArrayList<>();
        String[] color = {
  "♥","♠","♣","◆"};
        String[] num = {
  "A","2","3","4","5","6","7","8","9","10","J","Q","K"};
        for(String str:num) {
            for(String str1:color) {
                String poker = str1.concat(str);
                list.add(poker);
            }
        }
        list.add("♀");
        list.add("♂");
        for(int i=0;i<54;i++) {
   
                map.put(i, list.get(i));
            }
        Set<Integer> keyset = map.keySet();
        List<Integer> list1 = new ArrayList<>();
        for(Integer count:keyset){
            list1.add(count);
            }
        //洗牌三次
        Collections.shuffle(list1);
        Collections.shuffle(list1);
        Collections.shuffle(list1);

        Set<Integer> player01 = new TreeSet<>();
        Set<Integer> player02 = new TreeSet<>();
        Set<Integer> player03 = new TreeSet<>();
        Set<Integer> dipai = new TreeSet<>();
        //发牌
        for(int i=0;i<list1.size();i++) {
   
            if(i<51&&i%3 == 0) {
                player01.add(list1.get(i));
            }
            if(i<51&&i%3 == 1) {
                player02.add(list1.get(i));
            }
            if(i<51&&i%3 == 2) {
                player03.add(list1.get(i));
            }if(i>=51)
                dipai.add(list1.get(i));


        }
        //玩家一的牌
        System.out.println("玩家一：");
        for(Integer i:player01) {
            System.out.print(map.get(i)+" ");
        }
        System.out.println("\n玩家二：");
        //玩家二的牌
        for(Integer i:player02) {
            System.out.print(map.get(i)+ " ");
        }

        System.out.println("\n玩家三：");
        //玩家三的牌
        for(Integer i:player03) {
            System.out.print(map.get(i)+ " ");
        }
        System.out.println("\n底牌：");
        //玩家一的牌
        for(Integer i:dipai) {
            System.out.print(map.get(i)+ " ");
        }
    }
}