jdk1.8,FtpClientUtil 上传、下载单个文件

  <!-- https://mvnrepository.com/artifact/commons-net/commons-net -->
        <dependency>
            <groupId>commons-net</groupId>
            <artifactId>commons-net</artifactId>
            <version>3.8.0</version>
        </dependency>

import java.io.*;

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


public class FtpClientUtil {
    private FTPClient ftp = new FTPClient();
    private String server = "192.168.1.10";
    private String username = "dev";
    private String password = "123456";

    /**
     * 上传单个文件
     *
     * @param filename
     * @param pathName
     * @param remoteFileName
     */
    public void upload(String filename, String pathName, String remoteFileName) {

//      ftp.configure(config);
        boolean error = false;
        try {
            int reply;
            ftp.connect(server);
            ftp.login(username, password);
            ftp.setFileType(FTP.BINARY_FILE_TYPE);
            ftp.changeWorkingDirectory(pathName);
            try (final InputStream input = new FileInputStream(filename)) {
                ftp.storeFile(remoteFileName, input);
            }
            System.out.println("Connected to " + server + ".");
            System.out.print(ftp.getReplyString());

            // After connection attempt, you should check the reply code to verify
            // success.
            reply = ftp.getReplyCode();

            if (!FTPReply.isPositiveCompletion(reply)) {
                ftp.disconnect();
                System.err.println("FTP server refused connection.");
                System.exit(1);
            }
            // transfer files
            ftp.logout();
        } catch (IOException e) {
            error = true;
            e.printStackTrace();
        } finally {
            if (ftp.isConnected()) {
                try {
                    ftp.disconnect();
                } catch (IOException ioe) {
                    // do nothing
                }
            }
            System.exit(error ? 1 : 0);
        }
    }
    public void download(String filename, String pathName, String remoteFileName) {

//      ftp.configure(config);
        boolean error = false;
        try {
            int reply;
            ftp.connect(server);
            ftp.login(username, password);
            ftp.setFileType(FTP.BINARY_FILE_TYPE);
            ftp.changeWorkingDirectory(pathName);
            try (final OutputStream output = new FileOutputStream(filename)) {
                ftp.retrieveFile(remoteFileName, output);
            }
            System.out.println("Connected to " + server + ".");
            System.out.print(ftp.getReplyString());

            // After connection attempt, you should check the reply code to verify
            // success.
            reply = ftp.getReplyCode();

            if (!FTPReply.isPositiveCompletion(reply)) {
                ftp.disconnect();
                System.err.println("FTP server refused connection.");
                System.exit(1);
            }
            // transfer files
            ftp.logout();
        } catch (IOException e) {
            error = true;
            e.printStackTrace();
        } finally {
            if (ftp.isConnected()) {
                try {
                    ftp.disconnect();
                } catch (IOException ioe) {
                    // do nothing
                }
            }
            System.exit(error ? 1 : 0);
        }
    }


    public static void main(String[] args) {

        String fileName = "D:/a.png";
        String pathName = "test";
        String remoteFileName = "a1.png";

        FtpClientUtil ftpc = new FtpClientUtil();
        //将D:/a.png 上传到/test/a1.png
        ftpc.upload(fileName, pathName, remoteFileName);

        fileName="D:/a2.jpg";
        //将/test/a1.png 下载到D:/a2.png
        ftpc.download(fileName, pathName, remoteFileName);

    }

}