Java怎么实现FTP的上传与下载功能

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！