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一、前言：
最近刚好需要实现这个功能：实现ftp的上传和下载。在网上找了下资料，总结了下。直接上代码：
二、代码示例：
首先使用到的maven依赖：
<dependency>
<groupId>commons-net</groupId>
<artifactId>commons-net</artifactId>
<version>1.4.1</version>
</dependency>
ftp工具类：
package com.left.util;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;
import org.apache.commons.net.ftp.FTPReply;
import java.io.*;
import java.net.SocketException;
/**
* <pre>
* @author : orange
* e-mail : [email protected]
* time : 2018/10/09 14:18
* desc : ftp下载工具
* version: 1.0
* </pre>
*/
@Slf4j
public class FtpUtil {
/**
* 获取FTPClient对象
*
* @param ftpHost FTP主机服务器
* @param ftpPassword FTP 登录密码
* @param ftpUserName FTP登录用户名
* @param ftpPort FTP端口 默认为21
* @return
*/
public static FTPClient getFTPClient(String ftpHost, String ftpUserName,
String ftpPassword, int ftpPort) {
FTPClient ftpClient = new FTPClient();
try {
ftpClient = new FTPClient();
ftpClient.connect(ftpHost, ftpPort);// 连接FTP服务器
ftpClient.login(ftpUserName, ftpPassword);// 登陆FTP服务器
if (!FTPReply.isPositiveCompletion(ftpClient.getReplyCode())) {
System.out.println("未连接到FTP，用户名或密码错误。");
ftpClient.disconnect();
} else {
System.out.println("FTP连接成功。");
}
} catch (SocketException e) {
e.printStackTrace();
System.out.println("FTP的IP地址可能错误，请正确配置。");
} catch (Exception e) {
e.printStackTrace();
System.out.println("FTP的端口错误,请正确配置。");
}
return ftpClient;
}
/*
* 从FTP服务器下载文件
*
* @param ftpHost FTP IP地址
* @param ftpUserName FTP 用户名
* @param ftpPassword FTP用户名密码
* @param ftpPort FTP端口
* @param ftpPath FTP服务器中文件所在路径 格式： ftptest/aa
* @param localPath 下载到本地的位置 格式：H:/download
* @param fileName 文件名称
*/
public static boolean downloadFtpFile(String ftpHost, String ftpUserName,
String ftpPassword, int ftpPort, String ftpPath, String localPath,
String fileName) {
FTPClient ftpClient = null;
try {
ftpClient = getFTPClient(ftpHost, ftpUserName, ftpPassword, ftpPort);
ftpClient.setControlEncoding("UTF-8"); // 中文支持
ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
ftpClient.enterLocalPassiveMode();
ftpClient.changeWorkingDirectory(ftpPath);
File localFile = new File(localPath + File.separatorChar + fileName);
OutputStream os = new FileOutputStream(localFile);
ftpClient.retrieveFile(fileName, os);
os.close();
ftpClient.logout();
} catch (FileNotFoundException e) {
log.info("没有找到" + ftpPath + "文件");
e.printStackTrace();
return false;
} catch (SocketException e) {
log.info("连接FTP失败.");
e.printStackTrace();
return false;
} catch (Exception e) {
log.info("文件读取错误。");
e.printStackTrace();
return false;
}
return true;
}
/**
* Description: 向FTP服务器上传文件
*
* @param ftpHost FTP服务器hostname
* @param ftpUserName 账号
* @param ftpPassword 密码
* @param ftpPort 端口
* @param ftpPath FTP服务器中文件所在路径 格式： ftptest/aa
* @param fileName ftp文件名称
* @param input 文件流
* @return 成功返回true，否则返回false
*/
public static boolean uploadFile(String ftpHost, String ftpUserName,
String ftpPassword, int ftpPort, String ftpPath,
String fileName, InputStream input) {
boolean success = false;
FTPClient ftpClient = null;
try {
int reply;
ftpClient = getFTPClient(ftpHost, ftpUserName, ftpPassword, ftpPort);
reply = ftpClient.getReplyCode();
if (!FTPReply.isPositiveCompletion(reply)) {
ftpClient.disconnect();
return success;
}
ftpClient.setControlEncoding("UTF-8"); // 中文支持
ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
ftpClient.enterLocalPassiveMode();
ftpClient.changeWorkingDirectory(ftpPath);
ftpClient.storeFile(fileName, input);
input.close();
ftpClient.logout();
success = true;
} catch (Exception e) {
e.printStackTrace();
} finally {
if (ftpClient.isConnected()) {
try {
ftpClient.disconnect();
} catch (IOException ioe) {
}
}
}
return success;
}
/**
* 方法描述：检验指定路径的文件是否存在ftp服务器中
*
* @param filePath 指定绝对路径的文件/TEST/20161010
* @return 存在返回true，不存在返回false
*/
public static boolean isFTPFileExist(String ftpHost, String ftpUserName,
String ftpPassword, int ftpPort, String fileName, String filePath) {
FTPClient ftpClient = null;
try {
ftpClient = getFTPClient(ftpHost, ftpUserName, ftpPassword, ftpPort);
ftpClient.setControlEncoding("GBK"); // 中文支持
ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
ftpClient.enterLocalPassiveMode();
// 进入文件所在目录，注意编码格式，以能够正确识别中文目录
ftpClient.changeWorkingDirectory(new String(filePath.getBytes("GBK"),
FTP.DEFAULT_CONTROL_ENCODING));
// 检验文件是否存在
InputStream is = ftpClient.retrieveFileStream(new String(fileName
.getBytes("GBK"), FTP.DEFAULT_CONTROL_ENCODING));
if (is == null || ftpClient.getReplyCode() == FTPReply.FILE_UNAVAILABLE) {
log.info("文件" + filePath + "/" + fileName + "不存在");
return false;
}
log.info("文件" + filePath + "/" + fileName + "存在");
if (is != null) {
is.close();
ftpClient.completePendingCommand();
}
} catch (Exception e) {
e.printStackTrace();
return false;
} finally {
if (ftpClient != null) {
try {
ftpClient.disconnect();
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
}
return true;
}
public static void main(String[] args) {
String ftpHost = "60.12.107.83";
String ftpUserName = "sl0571";
String ftpPassword = "sl123456";
int ftpPort = 10021;
String ftpPath = "/data/yzf_ftp/kwy_ftp";
String localPath = "E:\\card";
String fileName = "20181014.txt";
// FTPClient ftpClient = getFTPClient(ftpHost, ftpUserName, ftpPassword, ftpPort);
boolean ftpFileExist = isFTPFileExist(ftpHost, ftpUserName, ftpPassword, ftpPort, fileName, ftpPath);
if(ftpFileExist) {
boolean downloadFtpFile = downloadFtpFile(ftpHost, ftpUserName, ftpPassword, ftpPort, ftpPath, localPath, fileName);
System.out.println("下载结果:" + downloadFtpFile);
}
// }
}
}