java 双线程实现拷贝2个文件

在 Java 中，你可以通过创建两个独立的线程来并行地复制两个文件。以下是使用 `java.util.concurrent` 包中的 `ExecutorService` 和 `Callable` 接口的一个简单示例：

import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.concurrent.*;

public class FileCopyWithThreads {
    private static final int BUFFER_SIZE = 4096;

    public static void main(String[] args) throws IOException, InterruptedException {
        String sourcePath = "sourceFile.txt";
        String destinationPath = "destinationFile.txt";

        ExecutorService executor = Executors.newFixedThreadPool(2); // 创建固定大小的线程池

        CopyTask copyTaskSource = new CopyTask(sourcePath, destinationPath + "_source");
        CopyTask copyTaskDestination = new CopyTask(sourcePath, destinationPath);

        Future<Void> futureSource = executor.submit(copyTaskSource);
        Future<Void> futureDestination = executor.submit(copyTaskDestination);

        futureSource.get(); // 等待源文件复制完成
        futureDestination.get(); // 等待目标文件复制完成

        executor.shutdown(); // 关闭线程池

        System.out.println("Both files copied successfully.");
    }

    static class CopyTask implements Callable<Void> {
        private final String sourcePath;
        private final String outputPath;

        public CopyTask(String sourcePath, String outputPath) {
            this.sourcePath = sourcePath;
            this.outputPath = outputPath;
        }

        @Override
        public Void call() throws IOException {
            Path source = Paths.get(sourcePath);
            Path target = Paths.get(outputPath);

            try (BufferedInputStream in = Files.newInputStream(source);
                 BufferedOutputStream out = Files.newOutputStream(target)) {

                byte[] buffer = new byte[BUFFER_SIZE];
                while (in.read(buffer) != -1) {
                    out.write(buffer);
                }
            }
            return null;
        }
    }
}

在这个例子中，我们创建了两个 `CopyTask` 类的实例，每个任务负责复制其中一个文件。然后将它们提交给线程池处理。`call()` 方法实现了实际的文件复制操作。