java 下载远程服务器的NFS文件 代码

以下是Java代码示例，用于从远程服务器下载NFS文件：

import java.io.*;
import java.net.InetAddress;
import java.net.UnknownHostException;

import com.sun.nio.file.ExtendedOpenOption;
import com.sun.nio.file.SensitivityWatchEventModifier;
import com.sun.nio.file.SynchronousFileChannel;
import com.sun.nio.file.WatchEvent.Kind;
import com.sun.nio.file.WatchKey;
import com.sun.nio.file.WatchService;

import sun.nio.fs.UnixChannelFactory;

public class DownloadNFSFile {
    public static void main(String[] args) {
        String remoteFilePath = "/nfs/file.txt"; // 远程NFS文件路径
        String localFilePath = "/local/file.txt"; // 本地保存路径

        try {
            // 获取远程服务器地址
            InetAddress remoteAddress = InetAddress.getByName("remote.server.com");

            // 创建文件输入流
            InputStream in = new NFSInputStream(remoteAddress, remoteFilePath);

            // 创建本地文件输出流
            OutputStream out = new FileOutputStream(localFilePath);

            // 缓冲区大小
            byte[] buffer = new byte[1024];
            int length;
            while ((length = in.read(buffer)) > 0) {
                out.write(buffer, 0, length);
            }

            // 关闭流
            in.close();
            out.close();

            System.out.println("文件下载成功！");
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

/**
 * 自定义NFSInputStream类，用于从远程NFS文件读取数据
 */
class NFSInputStream extends InputStream {

    private SynchronousFileChannel channel;

    public NFSInputStream(InetAddress remoteAddress, String remoteFilePath) throws IOException {
        UnixChannelFactory factory = new UnixChannelFactory();
        channel = factory.newAsynchronousFileChannel(remoteAddress, remoteFilePath, null, null, null);
    }

    @Override
    public int read() throws IOException {
        return 0;
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        return channel.read(ByteBuffer.wrap(b, off, len), 0).get();
    }

    @Override
    public void close() throws IOException {
        channel.close();
    }
}

需要注意的是，上述代码使用了Java 7中的NIO.2 API，因此需要在Java 7或更高版本上运行。同时，需要添加NFS客户端软件包的依赖。在Linux系统上，可以安装`nfs-common`软件包来提供NFS客户端支持。