Java常用工具类 - 综合案例 - 《【后端】Java 技术基础》

Song.java

package com.player;
import java.util.Objects;
public class Song {
    private String id;
    private String name;
    private String singer;
    public Song(String id, String name, String singer) {
        this.id = id;
        this.name = name;
        this.singer = singer;
    }
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSinger() {
        return singer;
    }
    public void setSinger(String singer) {
        this.singer = singer;
    }
    @Override
    public String toString() {
        return "【歌曲信息】：" + "id为：" + id + ", 名称为：" + name + ", 演唱者为：" + singer;
    }
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Song)) return false;
        Song song = (Song) o;
        return getId().equals(song.getId()) &&
                getName().equals(song.getName()) &&
                getSinger().equals(song.getSinger());
    }
    @Override
    public int hashCode() {
        return Objects.hash(getId(), getName(), getSinger());
    }
}

PlayList.java

package com.player;
import java.util.ArrayList;
import java.util.List;
public class PlayList {
    private String playListName;
    private List<Song> musicList;
    public PlayList(String playListName) {
        this.playListName = playListName;
        musicList = new ArrayList<Song>();
    }
    // 将歌曲添加都播放列表
    public void addToPlayList(Song song) {
        boolean isExist = false;
        for (Song dbSong : musicList) {
            if (dbSong.equals(song)) {
                isExist = true;
                break;
            }
        }
        if (!isExist) {
            musicList.add(song);
        } else {
            System.out.println(song.getName() + "已经存在于播放列表中，添加失败！");
        }
    }
    // 通过歌曲id查询
    public Song searchSongById(String id) {
        Song song = null;
        for (Song dbSong : musicList) {
            if (dbSong.getId().equals(id)) {
                song = dbSong;
                break;
            }
        }
        return song;
    }
    // 通过歌曲名称查询
    public Song searchSongByName(String name) {
        Song song = null;
        for (Song dbSong : musicList) {
            if (dbSong.getName().equals(name)) {
                song = dbSong;
                break;
            }
        }
        return song;
    }
    // 修改播放列表中的歌曲信息
    public void updateSong(String id, Song song) {
        Song dbSong = searchSongById(id);
        if (dbSong == null) {
            System.out.println("没有找到id为" + id + "对应的歌曲信息");
        } else {
            musicList.remove(dbSong);
            musicList.add(song);
            System.out.println("修改成功！");
        }
    }
    // 删除播放列表中的歌曲信息
    public void deleteSong(String id) {
        Song dbSong = searchSongById(id);
        if (dbSong == null) {
            System.out.println("没有找到id为" + id + "对应的歌曲信息");
        } else {
            musicList.remove(dbSong);
            System.out.println("删除成功！");
        }
    }
    // 显示播放列表中的所有数据
    public void displayAllSong() {
        System.out.println("播放列表中的所有歌曲为：");
        for (Song song : musicList) {
            System.out.println(song);
        }
    }
    public String getPlayListName() {
        return playListName;
    }
    public void setPlayListName(String playListName) {
        this.playListName = playListName;
    }
    public List<Song> getMusicList() {
        return musicList;
    }
    public void setMusicList(List<Song> musicList) {
        this.musicList = musicList;
    }
}

PlayListCollection.java

package com.player;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
public class PlayListCollection {
    // 为什么这里用Map，是因为可以比较好的管理播放器
    // 试想一下，如果也像PlayList一样定义仅仅定义name和list属性，那么要在哪里管理这些name和list呢
    Map<String, PlayList> playListMap;  // 存放播放列表的集合
    public PlayListCollection() {
        playListMap = new HashMap<String, PlayList>();
    }
    // 添加播放列表
    public void addPlayList(PlayList playList) {
        playListMap.put(playList.getPlayListName(), playList);
    }
    // 删除播放列表
    public void deletePlayList(PlayList playList) {
        playListMap.remove(playList.getPlayListName());
        System.out.println("删除成功！");
    }
    // 查询播放列表
    public PlayList searchPlayListByName(String playListName) {
        PlayList playList = null;
        Set<String> playListSet = playListMap.keySet();
        for (String key : playListSet) {
            if (key.equals(playListName)) {
                playList = playListMap.get(key);
                break;
            }
        }
        return playList;
    }
    // 显示所有播放列表的名称
    public void displayListName() {
        Set<String> playListSet = playListMap.keySet();
        System.out.println("播放列表名称为：");
        for (String key : playListSet) {
            System.out.println(key);
        }
    }
    public Map<String, PlayList> getPlayListMap() {
        return playListMap;
    }
    public void setPlayListMap(Map<String, PlayList> playListMap) {
        this.playListMap = playListMap;
    }
}

TestDemo.java

package com.player;
import java.util.Scanner;
public class TestDemo {
    // 主菜单
    public void mainMenu() {
        System.out.println("=======================================");
        System.out.println("                 主菜单                 ");
        System.out.println("            1 -- 播放列表管理            ");
        System.out.println("            2 -- 播放器管理              ");
        System.out.println("            0 -- 退出                   ");
        System.out.println("=======================================");
    }
    // 播放列表管理菜单
    public void playListMenu() {
        System.out.println("=======================================");
        System.out.println("          播放列表管理                   ");
        System.out.println("     1 -- 将歌曲添加到主播放列表          ");
        System.out.println("     2 -- 将歌曲添加到普通播放列表         ");
        System.out.println("     3 -- 通过歌曲id查询播放列表中的歌曲    ");
        System.out.println("     4 -- 通过歌曲名称查询播放列表中的歌曲  ");
        System.out.println("     5 -- 修改播放列表中的歌曲            ");
        System.out.println("     6 -- 删除播放列表中的歌曲            ");
        System.out.println("     7 -- 显示播放列表中的所有歌曲         ");
        System.out.println("     9 -- 返回上一级菜单                 ");
        System.out.println("=======================================");
    }
    // 播放器菜单
    public void playerMenu() {
        System.out.println("=======================================");
        System.out.println("          播放器管理                    ");
        System.out.println("     1 -- 向播放器添加播放列表            ");
        System.out.println("     2 -- 从播放器删除播放列表            ");
        System.out.println("     3 -- 通过名字查询播放列表信息         ");
        System.out.println("     4 -- 显示所有播放列表名称            ");
        System.out.println("     9 -- 返回上一级菜单                 ");
        System.out.println("=======================================");
    }
    // 主流程
    public void test() {
        TestDemo testDemo = new TestDemo();
        Scanner scanner = new Scanner(System.in);
        int input = 0;
        // 创建一个播放列表容器
        PlayListCollection playListCollection = new PlayListCollection();
        // 创建主播放列表
        PlayList mainPlayList = new PlayList("主播放列表");
        // 将主播放列表添加到播放器
        playListCollection.addPlayList(mainPlayList);
        while (true) {
            testDemo.mainMenu();
            System.out.println("请输入对应数字进行操作：");
            try {
                input = scanner.nextInt();
            } catch (Exception e) {
                System.out.println("请输入数字！");
                scanner.next();
                continue;
            }
            // 退出主菜单
            if (input == 0) {
                break;
            }
            switch (input) {
                case 1: // 播放列表管理
                    testDemo.playlistManage(playListCollection);
                    break;
                case 2: // 播放器管理
                    testDemo.playerManage(playListCollection);
                    break;
                default:
                    System.out.println("该数字没有对应的操作");
                    break;
            }
        }
    }
    // 播放列表管理
    public void playlistManage(PlayListCollection playListCollection) {
        TestDemo testDemo = new TestDemo();
        PlayList mainPlayList = playListCollection.searchPlayListByName("主播放列表");
        Scanner scanner = new Scanner(System.in);
        int input = 0;
        while (true) {
            testDemo.playListMenu();
            System.out.println("请输入对应的数字对播放列表进行管理：");
            try {
                input = scanner.nextInt();
            } catch (Exception e) {
                System.out.println("请输入数字！");
                scanner.next();
                continue;
            }
            // 退出列表管理
            if (input == 9) {
                break;
            }
            switch (input) {
                case 1: {
                    System.out.println("将歌曲添加到主播放列表");
                    System.out.println("请输入要添加的歌曲的数量：");
                    int count = scanner.nextInt();
                    for (int i = 1; i <= count; i++) {
                        System.out.println("请输入第" + i + "首歌曲");
                        System.out.println("请输入歌曲的id：");
                        String strId = scanner.next();
                        System.out.println("请输入歌曲的名称：");
                        String strName = scanner.next();
                        System.out.println("请输入演唱者：");
                        String strSinger = scanner.next();
                        // 创建歌曲类的对象
                        Song song = new Song(strId, strName, strSinger);
                        mainPlayList.addToPlayList(song);
                    }
                    break;
                }
                case 2: {
                    System.out.println("将歌曲添加到普通播放列表");
                    System.out.println("请输入要添加的播放列表名称：");
                    String sName = scanner.next();
                    // 根据名称判断列表是否在播放器中存在
                    PlayList commonPlayList = playListCollection.searchPlayListByName(sName);
                    if (commonPlayList == null) {
                        System.out.println("该播放列表不存在，请先将播放列表添加到播放器中");
                    } else {
                        System.out.println("请输入要添加的歌曲的数量");
                        int count = scanner.nextInt();
                        for (int i = 0; i < count; i++) {
                            System.out.println("请输入第" + i + "首歌曲：");
                            System.out.println("请输入歌曲id：");
                            String strId = scanner.next();
                            // 首先判断该id的歌曲是否在主播放列表存在
                            Song song = mainPlayList.searchSongById(strId);
                            if (song == null) {
                                System.out.println("请输入歌曲名称：");
                                String strName = scanner.next();
                                System.out.println("请输入演唱者：");
                                String strSinger = scanner.next();
                                // 创建一个Song类的对象
                                song = new Song(strId, strName, strSinger);
                                // 分别将歌曲添加到普通播放列表和主播放列表
                                mainPlayList.addToPlayList(song);
                                commonPlayList.addToPlayList(song);
                            } else {
                                commonPlayList.addToPlayList(song);
                            }
                        }
                        System.out.println("主播放列表");
                        mainPlayList.displayAllSong();
                        System.out.println("普通播放列表");
                        commonPlayList.displayAllSong();
                    }
                    break;
                }
                case 3: {
                    System.out.println("通过歌曲id查询播放列表中的歌曲");
                    System.out.println("请输入要查询的播放列表名称");
                    String sName = scanner.next();
                    // 查询播放列表是否存在
                    PlayList playList = playListCollection.searchPlayListByName(sName);
                    if (playList == null) {
                        System.out.println("该播放列表不存在！");
                    } else {
                        System.out.println("请输入要查询的歌曲id：");
                        String strId = scanner.next();
                        Song song = playList.searchSongById(strId);
                        if (song == null) {
                            System.out.println("该歌曲在播放列表" + sName + "中不存在！");
                        } else {
                            System.out.println(song);
                        }
                    }
                    break;
                }
                case 4: {
                    System.out.println("通过歌曲名称查询播放列表中的歌曲");
                    System.out.println("请输入要查询的播放列表名称");
                    String sName = scanner.next();
                    // 查询播放列表是否存在
                    PlayList playList = playListCollection.searchPlayListByName(sName);
                    if (playList == null) {
                        System.out.println("该播放列表不存在！");
                    } else {
                        System.out.println("请输入要查询的歌曲名称：");
                        String strName = scanner.next();
                        Song song = playList.searchSongByName(strName);
                        if (song == null) {
                            System.out.println("该歌曲在播放列表" + sName + "中不存在！");
                        } else {
                            System.out.println(song);
                        }
                    }
                    break;
                }
                case 5: {
                    System.out.println("修改播放列表中的歌曲");
                    break;
                }
                case 6:
                    System.out.println("删除播放列表中的歌曲");
                    break;
                case 7: {
                    System.out.println("显示播放列表中的所有歌曲");
                    System.out.println("请输入要显示的播放列表名称");
                    String sName = scanner.next();
                    // 查询播放列表是否存在
                    PlayList playList = playListCollection.searchPlayListByName(sName);
                    if (playList == null) {
                        System.out.println("该播放列表不存在！");
                    } else {
                        playList.displayAllSong();
                    }
                    break;
                }
                default:
                    System.out.println("该数字没有对应的操作");
                    break;
            }
        }
    }
    // 播放器管理
    public void playerManage(PlayListCollection playListCollection) {
        TestDemo testDemo = new TestDemo();
        Scanner scanner = new Scanner(System.in);
        int input = 0;
        while (true) {
            testDemo.playerMenu();
            System.out.println("请输入对应的数字对播放器进行管理：");
            try {
                input = scanner.nextInt();
            } catch (Exception e) {
                System.out.println("请输入数字！");
                scanner.next();
                continue;
            }
            // 退出列表管理
            if (input == 9) {
                break;
            }
            switch (input) {
                case 1: {
                    System.out.println("向播放器添加播放列表");
                    System.out.println("输入要添加的播放列表名称：");
                    String playerName = scanner.next();
                    // 创建一个新的播放列表对象
                    PlayList commonPlayList = new PlayList(playerName);
                    // 将播放列表添加到播放器Map
                    playListCollection.addPlayList(commonPlayList);
                    break;
                }
                case 2: {
                    System.out.println("从播放器删除播放列表");
                    System.out.println("请输入要删除的播放列表名称：");
                    String playListName = scanner.next();
                    if (playListName.equals("主播放列表")) {
                        System.out.println("主播放列表不能删除");
                        break;
                    }
                    // 查询播放列表是否存在
                    PlayList playList = playListCollection.searchPlayListByName(playListName);
                    if (playList == null) {
                        System.out.println("该播放列表不存在！");
                    } else {
                        playListCollection.deletePlayList(playList);
                    }
                    break;
                }
                case 3: {
                    System.out.println("通过名字查询播放列表信息");
                    System.out.println("请输入要查询的播放列表名称：");
                    String playListName = scanner.next();
                    PlayList playList = playListCollection.searchPlayListByName(playListName);
                    if (playList == null) {
                        System.out.println("该播放列表不存在");
                    } else {
                        // 显示该播放盒列表名称及其所有的歌曲
                        playList.displayAllSong();
                    }
                    break;
                }
                case 4: {
                    System.out.println("显示所有播放列表名称");
                    playListCollection.displayListName();
                    break;
                }
                default:
                    System.out.println("该数字没有对应的操作");
                    break;
            }
        }
    }
    public static void main(String[] args) {
        TestDemo td = new TestDemo();
        // td.testSong();
        // td.testPlayList();
        // td.testPlayListCollection();
        td.test();
    }
}