用Java代码多线程，集合，网络通信，GUI,IO,写一个租车App

好的，下面是一个简单的租车App的Java代码示例，它包含多线程、集合、网络通信、GUI和IO等功能。

1. 首先创建一个Car类，表示汽车：

public class Car {
    private String id;  // 汽车编号
    private String name;  // 汽车名称
    private String type;  // 汽车类型
    private double price;  // 汽车租金
    private boolean isRented;  // 汽车是否已经租出

    public Car(String id, String name, String type, double price) {
        this.id = id;
        this.name = name;
        this.type = type;
        this.price = price;
        this.isRented = false;
    }

    // getter和setter方法
    // ...
}

2. 然后创建一个CarRentalSystem类，表示租车系统，其中包含了所有可租的汽车，以及租车和还车的功能：

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

public class CarRentalSystem {
    private List<Car> cars;  // 所有可租的汽车列表

    public CarRentalSystem() {
        this.cars = new ArrayList<>();
        // 初始化所有可租的汽车
        cars.add(new Car("001", "奔驰", "豪华车", 500.0));
        cars.add(new Car("002", "宝马", "豪华车", 450.0));
        cars.add(new Car("003", "别克", "商务车", 300.0));
        cars.add(new Car("004", "雪佛兰", "家庭车", 200.0));
        cars.add(new Car("005", "丰田", "家庭车", 180.0));
    }

    // 获取所有可租的汽车列表
    public List<Car> getCars() {
        return cars;
    }

    // 根据编号查找汽车
    public Car findCarById(String id) {
        for (Car car : cars) {
            if (car.getId().equals(id)) {
                return car;
            }
        }
        return null;
    }

    // 租车
    public synchronized boolean rentCar(String id) {
        Car car = findCarById(id);
        if (car != null && !car.isRented()) {
            car.setRented(true);
            return true;
        }
        return false;
    }

    // 还车
    public synchronized boolean returnCar(String id) {
        Car car = findCarById(id);
        if (car != null && car.isRented()) {
            car.setRented(false);
            return true;
        }
        return false;
    }
}

3. 接下来创建一个客户端界面，包含租车和还车的操作：

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.List;

public class CarRentalClient extends JFrame implements ActionListener {
    private static final long serialVersionUID = 1L;

    private JTextArea taInfo;  // 显示租车信息
    private JButton btnRent;  // 租车按钮
    private JButton btnReturn;  // 还车按钮
    private JComboBox<String> cbCars;  // 可租的汽车列表
    private CarRentalSystem rentalSystem;  // 租车系统
    private Socket socket;  // 与服务器连接的套接字
    private BufferedReader reader;  // 从服务器读取数据的输入流
    private PrintWriter writer;  // 向服务器发送数据的输出流

    public CarRentalClient() {
        setTitle("租车系统客户端");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 600, 400);
        setLayout(new BorderLayout());

        taInfo = new JTextArea();
        add(new JScrollPane(taInfo), BorderLayout.CENTER);

        JPanel panel = new JPanel();
        add(panel, BorderLayout.SOUTH);

        rentalSystem = new CarRentalSystem();
        List<Car> cars = rentalSystem.getCars();
        String[] carNames = new String[cars.size()];
        for (int i = 0; i < cars.size(); i++) {
            carNames[i] = cars.get(i).getName() + " (" + cars.get(i).getId() + ")";
        }
        cbCars = new JComboBox<>(carNames);
        panel.add(cbCars);

        btnRent = new JButton("租车");
        btnRent.addActionListener(this);
        panel.add(btnRent);

        btnReturn = new JButton("还车");
        btnReturn.addActionListener(this);
        panel.add(btnReturn);

        setVisible(true);

        connectToServer();
    }

    // 连接到服务器
    private void connectToServer() {
        try {
            socket = new Socket("localhost", 8888);
            reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            writer = new PrintWriter(socket.getOutputStream(), true);
            new Thread(new ServerListener()).start();
        } catch (Exception e) {
            taInfo.append("连接服务器失败：" + e.getMessage() + "\n");
        }
    }

    // 处理按钮事件
    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == btnRent) {
            String carId = rentalSystem.getCars().get(cbCars.getSelectedIndex()).getId();
            writer.println("rent," + carId);
        } else if (e.getSource() == btnReturn) {
            String carId = rentalSystem.getCars().get(cbCars.getSelectedIndex()).getId();
            writer.println("return," + carId);
        }
    }

    // 从服务器读取信息的线程
    private class ServerListener implements Runnable {
        @Override
        public void run() {
            try {
                while (true) {
                    String msg = reader.readLine();
                    if (msg != null) {
                        String[] parts = msg.split(",");
                        if (parts.length == 2) {
                            String action = parts[0];
                            String carId = parts[1];
                            if (action.equals("rent")) {
                                boolean success = rentalSystem.rentCar(carId);
                                if (success) {
                                    taInfo.append("租车成功！\n");
                                } else {
                                    taInfo.append("租车失败！\n");
                                }
                            } else if (action.equals("return")) {
                                boolean success = rentalSystem.returnCar(carId);
                                if (success) {
                                    taInfo.append("还车成功！\n");
                                } else {
                                    taInfo.append("还车失败！\n");
                                }
                            }
                        }
                    }
                }
            } catch (Exception e) {
                taInfo.append("与服务器连接断开：" + e.getMessage() + "\n");
            }
        }
    }

    public static void main(String[] args) {
        new CarRentalClient();
    }
}

4. 最后创建一个服务器程序，处理租车和还车的请求：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class CarRentalServer {
    private static CarRentalSystem rentalSystem = new CarRentalSystem();

    public static void main(String[] args) {
        try {
            ServerSocket serverSocket = new ServerSocket(8888);
            System.out.println("服务器已启动，等待客户端连接...");

            while (true) {
                Socket socket = serverSocket.accept();
                new Thread(new ClientHandler(socket)).start();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    // 处理客户端请求的线程
    private static class ClientHandler implements Runnable {
        private Socket socket;
        private BufferedReader reader;
        private PrintWriter writer;

        public ClientHandler(Socket socket) throws Exception {
            this.socket = socket;
            this.reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            this.writer = new PrintWriter(socket.getOutputStream(), true);
        }

        @Override
        public void run() {
            try {
                while (true) {
                    String msg = reader.readLine();
                    if (msg != null) {
                        String[] parts = msg.split(",");
                        if (parts.length == 2) {
                            String action = parts[0];
                            String carId = parts[1];
                            if (action.equals("rent")) {
                                boolean success = rentalSystem.rentCar(carId);
                                if (success) {
                                    writer.println("rent," + carId);
                                } else {
                                    writer.println("rent_fail," + carId);
                                }
                            } else if (action.equals("return")) {
                                boolean success = rentalSystem.returnCar(carId);
                                if (success) {
                                    writer.println("return," + carId);
                                } else {
                                    writer.println("return_fail," + carId);
                                }
                            }
                        }
                    }
                }
            } catch (Exception e) {
                System.out.println("客户端断开连接：" + e.getMessage());
            } finally {
                try {
                    reader.close();
                    writer.close();
                    socket.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

这个租车App的实现比较简单，仅供参考。实际上，一个完整的租车系统还需要考虑更多的功能，比如用户注册、登录、结算等等。