java从网络设备读取文件

import org.apache.commons.net.ftp.FTPClient;

import java.io.FileOutputStream;
import java.io.IOException;

public class FTPExample {
    public static void main(String[] args) {
        FTPClient ftpClient = new FTPClient();
        try {
            ftpClient.connect("ftp.example.com");
            ftpClient.login("username", "password");
            ftpClient.enterLocalPassiveMode();

            FileOutputStream fos = new FileOutputStream("localFile.txt");
            ftpClient.retrieveFile("remoteFile.txt", fos);
            fos.close();

            ftpClient.logout();
            ftpClient.disconnect();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import com.jcraft.jsch.*;

import java.io.FileOutputStream;
import java.io.IOException;

public class SFTPExample {
    public static void main(String[] args) {
        JSch jsch = new JSch();
        Session session = null;
        ChannelSftp channelSftp = null;
        try {
            session = jsch.getSession("username", "sftp.example.com", 22);
            session.setPassword("password");
            session.setConfig("StrictHostKeyChecking", "no");
            session.connect();

            channelSftp = (ChannelSftp) session.openChannel("sftp");
            channelSftp.connect();

            FileOutputStream fos = new FileOutputStream("localFile.txt");
            channelSftp.get("remoteFile.txt", fos);
            fos.close();

            channelSftp.disconnect();
            session.disconnect();
        } catch (JSchException | SftpException | IOException e) {
            e.printStackTrace();
        }
    }
}

import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;

public class HTTPExample {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://example.com/remoteFile.txt");
            ReadableByteChannel readableByteChannel = Channels.newChannel(url.openStream());
            FileOutputStream fileOutputStream = new FileOutputStream("localFile.txt");

            fileOutputStream.getChannel().transferFrom(readableByteChannel, 0, Long.MAX_VALUE);

            fileOutputStream.close();
            readableByteChannel.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}