这篇文章主要讲解了“Java怎么实现FTP的上传与下载功能”，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习“Java怎么实现FTP的上传与下载功能”吧！
JAVA操作FTP服务器，只需要创建一个FTPClient即可，所有的操作都封装在FTPClient中，JDK自带的有FTPClient（sun.net.ftp.FtpClient），也可以用第三方的FTPClient，一般使用apache的FTPClient（org.apache.commons.net.ftp.FTPClient），本文将使用apache的FTPClient，API都大同小异
关键依赖：commons-net
对常用操作（上传、下载）封装成工具类
package com.day0322;import org.apache.commons.io.IOUtils;import org.apache.commons.lang3.StringUtils;import org.apache.commons.net.ftp.FTPClient;import org.apache.commons.net.ftp.FTPReply;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;public class FTPUtil { private static final Logger log = LoggerFactory.getLogger(FTPUtil.class); private static final int BUFFER_SIZE = 1024 * 1024 * 4; private static String LOCAL_CHARSET = "GBK"; private static final String CHARSET_UTF8 = "UTF-8"; private static final String OPTS_UTF8 = "OPTS UTF8"; private static final String SERVER_CHARSET = "ISO-8859-1"; private static FTPClient ftpClient = null; private static void login(OaFtp oaFtp) { ftpClient = new FTPClient(); try { ftpClient.connect(oaFtp.getIp(), Integer.valueOf(oaFtp.getPort())); ftpClient.login(oaFtp.getName(), oaFtp.getPwd()); ftpClient.setBufferSize(BUFFER_SIZE); ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE); int reply = ftpClient.getReplyCode(); if (!FTPReply.isPositiveCompletion(reply)) { closeConnect(); } } catch (Exception e) { log.error("",e); throw new RuntimeException(e); } } private static void closeConnect() { if (ftpClient != null && ftpClient.isConnected()) { try { ftpClient.logout(); ftpClient.disconnect(); } catch (IOException e) { log.error("",e); } } } private static String changeEncoding(String ftpPath) { String directory = null; try { if (FTPReply.isPositiveCompletion(ftpClient.sendCommand(OPTS_UTF8, "ON"))) { LOCAL_CHARSET = CHARSET_UTF8; } directory = new String(ftpPath.getBytes(LOCAL_CHARSET), SERVER_CHARSET); } catch (Exception e) { log.error("",e); } return directory; } private static void changeAndMakeWorkingDir(String path) { try { ftpClient.changeWorkingDirectory("/"); path = path.replaceAll("\\\\","/"); String[] path_array = path.split("/"); for (String s : path_array) { boolean b = ftpClient.changeWorkingDirectory(s); if (!b) { ftpClient.makeDirectory(s); ftpClient.changeWorkingDirectory(s); } } } catch (IOException e) { log.error("",e); throw new RuntimeException(e); } } public static boolean upload (OaFtp oaFtp, String filename, String dirPath, InputStream in) { login(oaFtp); if (!ftpClient.isConnected()) { return false; } boolean isSuccess = false; if (ftpClient != null) { try { if (FTPReply.isPositiveCompletion(ftpClient.sendCommand(OPTS_UTF8, "ON"))) { LOCAL_CHARSET = CHARSET_UTF8; } ftpClient.setControlEncoding(LOCAL_CHARSET); String path = changeEncoding(dirPath); changeAndMakeWorkingDir(path); isSuccess = ftpClient.storeFile(new String(filename.getBytes(), SERVER_CHARSET), in); } catch (Exception e) { log.error("",e); } finally { closeConnect(); } } return isSuccess; } public static void download (OaFtp oaFtp, String filename, String dirPath, FileOutputStream out) { // 登录 login(oaFtp); if (ftpClient != null) { try { String path = changeEncoding(dirPath); changeAndMakeWorkingDir(path); String[] fileNames = ftpClient.listNames(); if (fileNames == null || fileNames.length == 0) { return; } for (String fileName : fileNames) { String ftpName = new String(fileName.getBytes(SERVER_CHARSET), LOCAL_CHARSET); if (StringUtils.equals(ftpName,filename)) { InputStream in = ftpClient.retrieveFileStream(fileName); IOUtils.copy(in,out); } } } catch (IOException e) { log.error("",e); } finally { closeConnect(); } } }}测试
上传
下载
感谢各位的阅读，以上就是“Java怎么实现FTP的上传与下载功能”的内容了，经过本文的学习后，相信大家对Java怎么实现FTP的上传与下载功能这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是编程网，小编将为大家推送更多相关知识点的文章，欢迎关注！
