Java通过FTP实现上传下载

今天是2022年9月27日，突发灵感再java中如何通过ftp实现上传以及下载，那么此文Java通过FTP实现上传下载为大家讲述一整套流程。

添加依赖

<!-- Sftp工具 -->
<dependency>
    <groupId>com.jcraft</groupId>
    <artifactId>jsch</artifactId>
    <version>0.1.54</version>
</dependency>

SFTP工具类

import java.io.File;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;
import java.util.Vector;

import org.apache.log4j.Logger;

import com.jcraft.jsch.*;
import com.jcraft.jsch.ChannelSftp.LsEntry;

public class SftpClientUtil
{
  private static final Logger logger = Logger.getLogger(SftpClientUtil.class);

  /** Sftp */
  private ChannelSftp sftp = null;
  /** 主机 */
  private String host = "";
  /** 端口 */
  private int port = 0;
  /** 用户名 */
  private String username = "";
  /** 密码 */
  private String password = "";

  /**
   * 构造函数
   *
   * @param host
   *            主机
   * @param port
   *            端口
   * @param username
   *            用户名
   * @param password
   *            密码
   *
   */
  public SftpClientUtil(String host, int port, String username, String password)
  {

    this.host = host;
    this.port = port;
    this.username = username;
    this.password = password;
  }

  /**
   * 连接sftp服务器
   * 
   * @throws Exception
   */
  public void connect() throws Exception
  {

    JSch jsch = new JSch();
    Session sshSession = jsch.getSession(this.username, this.host, this.port);
    logger.debug(SftpClientUtil.class + "Session created.");

    sshSession.setPassword(password);
    Properties sshConfig = new Properties();
    sshConfig.put("StrictHostKeyChecking", "no");
    sshSession.setConfig(sshConfig);
    sshSession.connect(20000);
    logger.debug(SftpClientUtil.class + " Session connected.");

    logger.debug(SftpClientUtil.class + " Opening Channel.");
    Channel channel = sshSession.openChannel("sftp");
    channel.connect();
    this.sftp = (ChannelSftp) channel;
    logger.debug(SftpClientUtil.class + " Connected to " + this.host + ".");
  }

  /**
   * Disconnect with server
   * 
   * @throws Exception
   */
  public void disconnect() throws Exception
  {
    if (this.sftp != null)
    {
      if (this.sftp.isConnected())
      {
        this.sftp.disconnect();
      } else if (this.sftp.isClosed())
      {
        logger.debug(SftpClientUtil.class + " sftp is closed already");
      }
    }
  }

  /**
   * 下载单个文件
   *
   * @param directory
   *            下载目录
   * @param downloadFile
   *            下载的文件
   * @param saveDirectory
   *            存在本地的路径
   * 
   * @throws Exception
   */
  public void download(String directory, String downloadFile, String saveDirectory) throws Exception
  {
    File pathFile = new File(saveDirectory);
    if (!pathFile.exists())
    {
      pathFile.mkdirs();
    }

    String saveFile = saveDirectory + "//" + downloadFile;

    this.sftp.cd(directory);
    File file = new File(saveFile);
    this.sftp.get(downloadFile, new FileOutputStream(file));
  }

  /**
   * 下载目录下全部文件
   *
   * @param directory
   *            下载目录
   * 
   * @param saveDirectory
   *            存在本地的路径
   * 
   * @throws Exception
   */
  public void downloadByDirectory(String directory, String saveDirectory) throws Exception
  {
    String downloadFile = "";
    List<String> downloadFileList = this.listFiles(directory);
    Iterator<String> it = downloadFileList.iterator();

    while (it.hasNext())
    {
      downloadFile = it.next().toString();
      if (downloadFile.toString().indexOf(".") < 0)
      {
        continue;
      }
      this.download(directory, downloadFile, saveDirectory);
    }
  }

  /**
   * 新建子目录
   *
   * @param dst 远程服务器路径
   *
   * @throws Exception
   */
  public void mkdir(String dst, String subDir) throws Exception
  {
    this.sftp.cd(dst);
    try {
      if(this.sftp.ls(subDir).size() > 0) {
        return;
      }
    } catch (SftpException se) {
      logger.error(se.getMessage());
    }

    this.sftp.mkdir(subDir);
  }

  /**
   * 上传单个文件
   *
   * @param src 本地文件
   * @param dst 远程服务器路径
   *
   * @throws Exception
   */
  public void upload(String src, String dst) throws Exception
  {
    this.sftp.put(src, dst);
  }

  /**
   * 列出目录下的文件
   *
   * @param directory
   *            要列出的目录
   * 
   * @return list 文件名列表
   *
   * @throws Exception
   */
  @SuppressWarnings("unchecked")
  public List<String> listFiles(String directory) throws Exception
  {

    Vector fileList;
    List<String> fileNameList = new ArrayList<String>();

    fileList = this.sftp.ls(directory);
    Iterator it = fileList.iterator();

    while (it.hasNext())
    {
      String fileName =((LsEntry) it.next()).getFilename();
      if (".".equals(fileName) || "..".equals(fileName))
      {
        continue;
      }
      fileNameList.add(fileName);

    }

    return fileNameList;
  }
  
  public ChannelSftp getSftp()
  {
    return sftp;
  }

  public void setSftp(ChannelSftp sftp)
  {
    this.sftp = sftp;
  }
}

SFTP测试类

public static void main(String[] args) {
        String host = "192.xx.xx.xxx";// 主机地址
        String port = "22";// 主机端口
        String username = "xxxx";// 服务器用户名
        String password = "xxxxx";// 服务器密码
        SftpClientUtil sftpClientUtil = new SftpClientUtil(host, Integer.parseInt(port), username, password);
        try {
            logger.info("开始连接sftp服务器");
            try {
                sftpClientUtil.connect();
            } catch (Exception e) {
                logger.error("开始连接sftp服务器报错:{}" + e.getMessage());
            }
            // 文件所在本地路径
            String srcUrl = "/Users/zhuangjy/Desktop/";
            // 上传到服务器路径
            String dstUrl = "/usr/local/test" + File.separator;
            // SFTP 创建路径
            sftpClientUtil.mkdir("/usr/local/", "test");
            // 上传文件
            sftpClientUtil.upload("/Users/zhuangjy/Desktop/test.txt", dstUrl + "test.txt");
            // 下载文件
            sftpClientUtil.download("/usr/local/test/", "test.txt", "/Users/zhuangjy/Desktop/");
        } catch (Exception e) {
            logger.error("下载文件出错" + e.getMessage());
        }  finally {
            try {
                sftpClientUtil.disconnect();
            } catch (Exception e) {
                logger.error("获取文件：" + e.getMessage());
            }
        }
}