1.展示多部电影信息
新建一个实体类Movie
package com.test.集合框架.p137;
public class Movie {
private String name;//电影名称
private double score;//电影评分
private String actor;//电影主演
public Movie() {
}
public Movie(String name, double score, String actor) {
this.name = name;
this.score = score;
this.actor = actor;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getScore() {
return score;
}
public void setScore(double score) {
this.score = score;
}
public String getActor() {
return actor;
}
public void setActor(String actor) {
this.actor = actor;
}
@Override
public String toString() {
return "Movie{" +
"name='" + name + '\'' +
", score=" + score +
", actor='" + actor + '\'' +
'}';
}
}
新建一个MovieTest类
package com.test.集合框架.p137;
import java.util.ArrayList;
import java.util.Collection;
/**
* 目标：完成电影信息的展示。
* new Movie("《肖生克的救赎》" , 9.7 , "罗宾斯")
* new Movie("《霸王别姬》" , 9.6 , "张国荣、张丰毅")
* new Movie("《阿甘正传》" , 9.5 , "汤姆.汉克斯")
*/
public class MovieTest {
public static void main(String[] args) {
// 1、创建一个集合容器负责存储多部电影对象。
Collection<Movie> movies = new ArrayList<>();
movies.add( new Movie("《肖生克的救赎》" , 9.7 , "罗宾斯"));
movies.add( new Movie("《霸王别姬》" , 9.6 , "张国荣、张丰毅"));
movies.add( new Movie("《阿甘正传》" , 9.5 , "汤姆.汉克斯"));
System.out.println(movies);
for (Movie movie : movies) {
System.out.println("电影名：" + movie.getName());
System.out.println("评分：" + movie.getScore());
System.out.println("主演：" + movie.getActor());
System.out.println("---------------------------------------------");
}
}
}
运行结果：
2.两个内容一样的对象，让HashSet集合去重
自定义的类型的对象，比如两个内容一样的学生对象，如果让HashSet集合能够去重复！
现象举例：
新建一个学生类
package com.test.集合框架.p140;
public class Student {
private String name;
private int age;
private double height;
public Student() {
}
public Student(String name, int age, double height) {
this.name = name;
this.age = age;
this.height = height;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public double getHeight() {
return height;
}
public void setHeight(double height) {
this.height = height;
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
", height=" + height +
'}';
}
}
再创建一个HashSetTest类
package com.test.集合框架.p140;
import java.util.HashSet;
import java.util.Set;
/**
* 目标：自定义的类型的对象，比如两个内容一样的学生对象，如果让HashSet集合能够去重复！
*/
public class HashSetTest {
public static void main(String[] args) {
Set<Student> students = new HashSet<>();
Student s1 = new Student("至尊宝", 28, 169.6);
Student s2 = new Student("蜘蛛精", 23, 169.6);
Student s3 = new Student("蜘蛛精", 23, 169.6);
Student s4 = new Student("牛魔王", 48, 169.6);
students.add(s1);
students.add(s2);
students.add(s3);
students.add(s4);
System.out.println(students);
}
}
结论：如果希望Set集合认为2个内容一样的对象是重复的， 必须重写对象的hashCode()和equals()方法
修改学生类-重写hashCode()和equals()方法
再运行HashSetTest类-就没有两个“蜘蛛精”对象了
3.斗地主游戏
分析业务需求
- 总共有54张牌
- 点数: "3","4","5","6","7","8","9","10","J","Q","K","A","2“
- 花色: "♠", "♥", "♣", "♦“
- 大小王: "👲" , "🃏“
- 斗地主：发出51张牌，剩下3张做为底牌。
分析实现
- 在启动游戏房间的时候，应该提前准备好54张牌
- 接着，需要完成洗牌、发牌、对牌排序、看牌
新建Card类（牌）
package com.test.集合框架.p144;
/**
* @description:牌类
* @author： Admin
* @create： 2024/9/27 9:30
*/
public class Card {
private String number;//点数
private String color;//牌的花色
private int size;//每张牌是存在大小的
public Card() {
}
public Card(String number, String color, int size) {
this.number = number;
this.color = color;
this.size = size;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public String getColor() {
return color;
}
public void setColor(String color) {
this.color = color;
}
public int getSize() {
return size;
}
public void setSize(int size) {
this.size = size;
}
@Override
public String toString() {
return color+number+"-->"+size;
}
}
新建房间类Room
package com.test.集合框架.p144;
import java.util.*;
/**
* @description:房间类
* @author： Admin
* @create： 2024/9/27 9:32
*/
public class Room {
//必须有一副牌
private List<Card> allCards=new ArrayList<>();
public Room() {
//点数：一个数确定了，类型确定
String[] numbers={"3","4","5","6","7","8","9","10","J","Q","K","A","2"};
//花色
String[] colors={"♠", "♥", "♣", "♦"};
int size=0;//表示每张牌的大小
//点色与花色组合起来
for (String number : numbers) {
size++;
for (String color : colors) {
Card c=new Card(number,color,size);
allCards.add(c);
}
}
//单独存入大小王
Card c1 = new Card("", "🃏" , ++size);
Card c2 = new Card("", "👲" , ++size);
Collections.addAll(allCards,c1,c2);
System.out.println("这是一副新牌："+allCards);
}
//游戏启动方法
public void start() {
//1.洗牌
Collections.shuffle(allCards);
System.out.println("洗牌后："+allCards);
//2发牌
List<Card> LinHuChong=new ArrayList<>();
List<Card> JiuGuoZhi=new ArrayList<>();
List<Card> RenYingYing=new ArrayList<>();
// 正式发牌给这三个玩家，依次发出51张牌，剩余3张做为底牌。
// allCards = [♥3, ♣10, ♣4, ♥K, ♦Q, ♣2, 🃏, ♣8, ....
// 0 1 2 3 4 5 6 ... % 3
for(int i=0;i<allCards.size()-3;i++){
Card c=allCards.get(i);
//判断牌发给谁
if(i%3==0){
//给LinHuChong发牌
LinHuChong.add(c);
} else if (i%3==1) {
//给JiuGuoZhi发牌
JiuGuoZhi.add(c);
} else if (i%3==2) {
//给Renyingying发牌
RenYingYing.add(c);
}
}
//对3个玩家的牌排序
sortCards(LinHuChong);
sortCards(JiuGuoZhi);
sortCards(RenYingYing);
//4.看牌
System.out.println("啊冲："+LinHuChong);
System.out.println("啊智："+JiuGuoZhi);
System.out.println("茵茵："+RenYingYing);
List<Card> lastThreadCards=allCards.subList(allCards.size()-3,allCards.size());
System.out.println("最后三张底牌："+lastThreadCards);
//假设JiuGuoZhi抢到地主
JiuGuoZhi.addAll(lastThreadCards);
sortCards(JiuGuoZhi);
System.out.println("啊智抢到地主后的牌："+JiuGuoZhi);
}
private void sortCards(List<Card> cards){
Collections.sort(cards, new Comparator<Card>() {
@Override
public int compare(Card o1, Card o2) {
return o2.getSize()- o1.getSize();//降序
}
});
}
}
新建Demo类
package com.test.集合框架.p144;
/**
* @description
* @author： Admin
* @create： 2024/9/27 9:56
*/
public class Demo {
public static void main(String[] args) {
Room r=new Room();
r.start();
}
}
运行：
4.统计投票人数 -Map集合
分析：
- 将80个学生选择的数据拿到程序中去，[A, A, B , A, B, C, D, ...]
- 准备一个Map集合用于存储统计的结果，Map<String，Integer>，键是景点，值代表投票数量。
- 遍历80个学生选择的景点，每遍历一个景点，就看Map集合中是否存在该景点，不存在存入“景点=1“，存在则其对应值+1
package com.test.集合框架;
import java.util.*;
/**
* @description
* @author： Admin
* @create： 2024/9/23 14:55
*/
public class p146 {
public static void main(String[] args) {
//建一个list集合，存放80位选择的景点信息
List<String> all=new ArrayList<>();
//数组存放景点
String[] view={"A","B","C","D"};
//生成一个随机数
Random r =new Random();
for (int i=1;i<=80;i++){
int number=r.nextInt(0,4);//包前不包后 0 1 2 3
all.add(view[number]);
}
//生成80个景点
System.out.println("所有景点信息："+all);
//统计
Map<String,Integer> result=new HashMap<>();
for (String s : all) {
if(result.containsKey(s)){
//包含该键，值就得+1
result.put(s,result.get(s)+1);
}else {
//不包含该键，值设为1---第一次有这个键
result.put(s,1);
}
}
System.out.println(result);
}
}
运行
5.记录省份以及对应的城市信息-Map集合案例（嵌套的集合）
package com.test.集合框架;
import java.util.*;
public class p148 {
public static void main(String[] args) {
// 1、定义一个Map集合存储全部的省份信息，和其对应的城市信息。
Map<String, List<String>> map = new HashMap<>();
List<String> cities1 = new ArrayList<>();
Collections.addAll(cities1, "南京市","扬州市","苏州市" ,"无锡市","常州市");
map.put("江苏省", cities1);
List<String> cities2 = new ArrayList<>();
Collections.addAll(cities2, "武汉市","孝感市","十堰市","宜昌市","鄂州市");
map.put("湖北省", cities2);
List<String> cities3 = new ArrayList<>();
Collections.addAll(cities3, "石家庄市","唐山市", "邢台市", "保定市", "张家口市");
map.put("河北省", cities3);
System.out.println(map);
List<String> cities = map.get("湖北省");
for (String city : cities) {
System.out.println(city);
}
map.forEach((p, c) -> {
System.out.println(p + "----->" + c);
});
}
}
运行：
