java - 将 ArrayList 添加到 SQL 数据库？ (文件管理)

Question

我正在为我的数据结构编程课做大学作业。我们正在为这项任务分组工作，所以我目前正在处理我的一个队友项目。我添加了本地 READ/WRITE 代码，这样我就可以将数组列表保存到本地 .dat 文件中。但是，对于额外的标记，我可以进行高级文件处理。

我决定采用 MySQL 方法。

该程序是一个篮球运动员 CRUD 系统，您可以在其中添加一名球员、他们所在的球队、地址、姓名和号码。

我有 5 个类(class)。一个教练类(目前什么都不做)，一个球员类和一个团队类。这些类只有 set、get 和 toString 方法。

最后两个类是 BasketBallSystem 类，它具有所有 GUI、方法、菜单等。

package ie.wit.basketball;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

public class BasketballSystem {

public ArrayList<Team> getTeams() {
    return teams;
}

private ArrayList<Team> teams = new ArrayList<>();

public BasketballSystem() throws Exception {
    teams=BasketballFile.ArrayListFromFile();
    if (teams.size() == 0)
    {       Team t = new Team("Golden State Warriors", 10);
    teams.add(t);

    t.getPlayers().add(new Player("Donna Kinsella", 666));
    t.getPlayers().add(new Player("Tommy White", 21));

    t.setTheCoach(new Coach("Tom Jones"));

    for (Player p : t.getPlayers()) {
        System.out.println(p.getPlayerName());
    }

    t = new Team("Florida Falcons", 10);
    t.getPlayers().add(new Player("Don Keating", 76));
    t.getPlayers().add(new Player("Tom Green", 22));
    teams.add(t);
    }

}

public int menuMain() {

    JLabel addPlayer = new JLabel("1. Add a Player");
    JLabel listPlayers = new JLabel("2. List all Players");
    JLabel updateDetails = new JLabel("3. Update Players Details");
    JLabel deletePlayers = new JLabel("4. Delete a player");
    JLabel exitSys = new JLabel("5. Exit");
    JTextField optionField = new JTextField();

    Object[] message = new Object[6];

    message[0] = addPlayer;
    message[1] = listPlayers;
    message[2] = updateDetails;
    message[3] = deletePlayers;
    message[4] = exitSys;
    message[5] = optionField;

    JOptionPane.showMessageDialog(null, message);
    try{
    return Integer.parseInt(optionField.getText());
    }
    catch(NumberFormatException e)
    {
        return 5;
    }
}

public static void main(String[] args) throws Exception {
    // TODO Auto-generated method stub
    // new BasketballSystem();

    int choice;

    BasketballSystem b = new BasketballSystem();

    do {

        choice = b.menuMain();

        switch (choice) {
        case 1:
            b.addPlayer();
            break;
        case 2:
            b.listPlayers();
            break;
        case 3:
            b.updatePlayersDetails();
            break;
        case 4:
            b.removePlayer();
            break;
        case 5:
            JOptionPane.showMessageDialog(null, "Thank you for using this system.");
            BasketballFile.ArrayListToFile(b.getTeams());
            break;
        default:
            JOptionPane.showMessageDialog(null, "Invalid Entry, Please try again.");
        }
    } while (choice != 5);

}

private void updatePlayersDetails() {
    // TODO Auto-generated method stub

    String playerNumber = new String("Player Number");
    JTextField number = new JTextField("");
    String playerName = new String("Player Name");
    JTextField name = new JTextField("");
    String playerAddress = new String("Player Address");
    JTextField address = new JTextField("");

    String[] teamnames = new String[teams.size()];
    for (int i = 0; i < teams.size(); i++)
        teamnames[i] = teams.get(i).getTeamName();
    JComboBox<String> teamnamescombo = new JComboBox<String>(teamnames);

    Object message[] = new Object[6];

    message[0] = playerNumber;
    message[1] = number;
    message[2] = playerName;
    message[3] = name;
    message[4] = playerAddress;
    message[5] = address;

    int response = JOptionPane.showConfirmDialog(null, message, "Player Details Update",
            JOptionPane.OK_CANCEL_OPTION);

    if (response == JOptionPane.OK_OPTION) {
        try {
            int pnum = Integer.parseInt(number.getText());
            List<Player> players = teams.get(teamnamescombo.getSelectedIndex()).getPlayers();
            Iterator<Player> it = players.iterator();

            while (it.hasNext()) {
                Player p = it.next();
                if (p.getPlayerNumber() == pnum) {
                    p.setPlayerName(playerName);
                    p.setPlayerNumber(playerNumber);
                    p.setPlayerName(playerName);
                }
                // if (p.getPlayerAddress()==pAdd){
                JOptionPane.showMessageDialog(null, "Player's address has been successfully updated");
            }
        } catch (Exception e) {
            JOptionPane.showMessageDialog(null, "Error: Player number invalid");
        }
    }
}

private void removePlayer() {
    // TODO Auto-generated method stub

    String playerNumber = new String("Player Number");
    JTextField number = new JTextField("");

    String[] teamnames = new String[teams.size()];
    for (int i = 0; i < teams.size(); i++)
        teamnames[i] = teams.get(i).getTeamName();
    JComboBox<String> teamnamescombo = new JComboBox<String>(teamnames);

    Object message[] = new Object[3];

    message[0] = playerNumber;
    message[1] = number;
    message[2] = teamnamescombo;

    int response = JOptionPane.showConfirmDialog(null, message, "Player Removal", JOptionPane.OK_CANCEL_OPTION);

    if (response == JOptionPane.OK_OPTION) {

        int pnum = Integer.parseInt(number.getText());
        List<Player> players = teams.get(teamnamescombo.getSelectedIndex()).getPlayers();
        Iterator<Player> it = players.iterator();

        while (it.hasNext()) {
            Player p = it.next();
            if (p.getPlayerNumber() == pnum) {
                it.remove();
                JOptionPane.showMessageDialog(null, "Player has been successfully removed");
            }
        }
    }

}

private void listPlayers() {
    // TODO Auto-generated method stub
    // String

    for (Team t : teams) // for all teams
    {

        System.out.println("Team: " + t.getTeamName());
        for (Player p : t.getPlayers()) // for all player
        {
            System.out.println(
                    "Player: " + p.getPlayerName() + " " + p.getPlayerNumber() + " " + p.getPlayerAddress());

        }
    }
}

private void addPlayer() {
    // TODO Auto-generated method stub
    // String teamName
    String playerName = new String("Player name");
    String playerNumber = new String("Player Number");
    String playerAddress = new String("Player Address");
    JTextField name = new JTextField("");
    JTextField number = new JTextField("");
    JTextField address = new JTextField("");

    String[] teamnames = new String[teams.size()];
    for (int i = 0; i < teams.size(); i++)
        teamnames[i] = teams.get(i).getTeamName();
    JComboBox<String> teamnamescombo = new JComboBox<String>(teamnames);

    Object message[] = new Object[7];

    message[0] = playerName;
    message[1] = name;
    message[2] = playerNumber;
    message[3] = number;
    message[4] = playerAddress;
    message[5] = address;
    message[6] = teamnamescombo;

    int response = JOptionPane.showConfirmDialog(null, message, "Player Entry", JOptionPane.OK_CANCEL_OPTION);

    if (response == JOptionPane.OK_OPTION) {


        int pnum = Integer.parseInt(number.getText());
        Player newPlay = new Player(name.getText(), pnum);
        teams.get(teamnamescombo.getSelectedIndex()).getPlayers().add(newPlay);
        JOptionPane.showMessageDialog(null, "Player has been successfully Added");
    }   
        {

        }
        }



}

最后一个类是 BasketBallFile 类，它处理文件管理。

package ie.wit.basketball;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;

public class BasketballFile {

public static void ArrayListToFile(ArrayList<Team> al) throws Exception {


    try{
        File f=new File("mydata.dat");
        FileOutputStream fos=new FileOutputStream(f);
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(al);

        System.out.println("Written to file!");
        oos.close();
        fos.close();

    }catch(Exception e) { 
        System.out.println("Error: "+e.getMessage());
        throw e;
    }


}

public static ArrayList<Team> ArrayListFromFile() throws Exception {
    ArrayList<Team> al=new ArrayList<Team>();

    try{
        File f=new File("mydata.dat");
        FileInputStream fis=new FileInputStream(f);
        ObjectInputStream ois = new ObjectInputStream(fis);
        al=(ArrayList<Team>)ois.readObject();

        System.out.println("Read from file!");
        ois.close();
        fis.close();

    }catch(Exception e) { 
        System.out.println("Error: "+e.getMessage());

    }

    return al;

}


}

我不希望你告诉我具体怎么做，我只是不知道从哪里开始。我已经尝试用谷歌搜索这个，我尝试搜索教程，但我尝试的一切都没有用。我的 Java 知识非常基础，所以如果您能提供帮助，那就太好了。谢谢。

对不起，如果我也没有正确设置格式，这是我第一次使用这个网站。谢谢!

Answer 1

Java 中数据库管理的关键是 Java Persistence API .这是一个很大的话题，我个人只从 Java EE 的上下文中知道它，但是 it also works with Java SE .

仅具备基本的 Java 知识，这可能是一个巨大的飞跃，也许您应该在进入 ORM 的美妙世界之前充分了解关系数据库以及如何使用它们。对于大学作业中的额外分数，我可能只是将读/写转换为随机文件访问，而不是将整个列表一起序列化到文件中。 (这也不容易，但不需要您学习新概念。)