java实验代码实现多态，线程，文件读写

好的，我来为您展示一下 Java 实验代码实现多态、线程和文件读写的示例代码。

多态实现示例代码：

public class Shape {
    public void draw() {
        System.out.println("Drawing a shape");
    }
}

public class Circle extends Shape {
    public void draw() {
        System.out.println("Drawing a circle");
    }
}

public class Square extends Shape {
    public void draw() {
        System.out.println("Drawing a square");
    }
}

public class Main {
    public static void main(String[] args) {
        Shape shape1 = new Circle();
        Shape shape2 = new Square();
        
        shape1.draw();
        shape2.draw();
    }
}

线程实现示例代码：

public class MyThread extends Thread {
    public void run() {
        for(int i = 1; i <= 5; i++) {
            System.out.println("Thread " + Thread.currentThread().getId() + ": " + i);
        }
    }
}

public class Main {
    public static void main(String[] args) {
        MyThread thread1 = new MyThread();
        MyThread thread2 = new MyThread();
        
        thread1.start();
        thread2.start();
    }
}

文件读写实现示例代码：

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        // 写入文件
        try {
            FileWriter writer = new FileWriter("test.txt");
            writer.write("Hello World!");
            writer.close();
        } catch (IOException e) {
            System.out.println("An error occurred.");
            e.printStackTrace();
        }
        
        // 读取文件
        try {
            File file = new File("test.txt");
            Scanner scanner = new Scanner(file);
            while (scanner.hasNextLine()) {
                String data = scanner.nextLine();
                System.out.println(data);
            }
            scanner.close();
        } catch (IOException e) {
            System.out.println("An error occurred.");
            e.printStackTrace();
        }
    }
}

以上就是 Java 实验代码实现多态、线程和文件读写的示例代码，希望能对您有所帮助！