本文使用FTPClient对FTP进行文件操作，FTPClient工具需要添加Maven依赖。
<!-- commons-net FTP工具类--><dependency><groupId>commons-net</groupId><artifactId>commons-net</artifactId><version>3.6</version></dependency>
在测试文件上传过程中，发现中文名称的文件上传到FTP服务器乱码。
问题解决的思路是设置上传文件名称的编码格式为UTF-8，那么怎么设置呢？为了一劳永逸的方式解决文件上传下载均不会乱码，在FTP登录的时候设置字符编码，这样就不用担心乱码问题了。下面看代码
public static FTPClient connectFTP(String ip, int port, String uname, String pwd) throws IOException {FTPClient ftpClient = new FTPClient();// 优先设置编码格式，避免中文乱码ftpClient.setAutodetectUTF8(true);ftpClient.setCharset(CharsetUtil.UTF_8);ftpClient.setControlEncoding(CharsetUtil.UTF_8.name());ftpClient.connect(ip, port);boolean login = ftpClient.login(uname, pwd);if (!login) {throw new BusinessException("ftp连接失败，请检查配置");}ftpClient.enterLocalPassiveMode();ftpClient.setFileType(FTP.BINARY_FILE_TYPE);ftpClient.setBufferSize(DEFAULT_BUFFER_SIZE);return ftpClient;}
其中CharsetUtil使用的依赖包是netty的依赖，需要在Maven添加netty依赖。
<!-- netty-common --><dependency><groupId>ty</groupId><artifactId>netty-common</artifactId><version>4.1.77.Final</version></dependency>
下面提供一个简单的FTP工具类
import xxx.xxx.xxx.BusinessException;import ty.util.CharsetUtil;import lombok.extern.slf4j.Slf4j;import press.utils.IOUtils;import .ftp.FTP;import .ftp.FTPClient;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;/*** @author * @date /8/2 15:53* @description*/@Slf4jpublic class FtpUtils {private static final int DEFAULT_BUFFER_SIZE = 4096;/*** 上传文件** @param input输入流* @param uploadPath 保存路径* @param fileName 文件名（包含格式后缀）* @param ftpClient FTP客户端连接* @throws IOException*/public static void upload(InputStream input, String uploadPath, String fileName, FTPClient ftpClient) {try {// 判断路径是否存在，不存在则新建checkFTPPath(ftpClient, uploadPath);// 保存文件到路径ftpClient.storeFile(fileName, input);log.info("您的文件【{}】上传成功。", fileName);} catch (IOException e) {log.error("FTP上传文件时出错", e);throw new BusinessException("sys.file.fail");} finally {// 关闭连接IOUtils.closeQuietly(input);closeFTP(ftpClient);}}/*** 上传文件** @param input输入流* @param uploadPath 保存路径* @param fileName 文件名（包含格式后缀）* @param ip* @param port* @param uname* @param pwd* @throws IOException*/public static void upload(InputStream input, String uploadPath, String fileName, String ip, int port, String uname, String pwd) {FTPClient ftpClient = new FTPClient();try {// 获取FTP客户端ftpClient = connectFTP(ip, port, uname, pwd);// 判断路径是否存在，不存在则新建checkFTPPath(ftpClient, uploadPath);// 保存文件到路径ftpClient.storeFile(fileName, input);log.info("您的文件【{}】上传成功。", fileName);} catch (IOException e) {log.error("FTP上传文件时出错", e);throw new BusinessException("sys.file.fail");} finally {// 关闭连接IOUtils.closeQuietly(input);closeFTP(ftpClient);}}/*** 删除文件** @param path文件地址* @param ftpClient FTP客户端* @return* @throws IOException*/public static Boolean deleteFile(String path, FTPClient ftpClient) {Boolean flag = false;try {//删除if (ftpClient != null) {flag = ftpClient.deleteFile(path);log.info("您的文件【{}】删除成功。", path);}} catch (IOException e) {log.error("FTP删除文件时出错", e);throw new BusinessException("sys.file.delete.fail");} finally {closeFTP(ftpClient);}return flag;}/*** 删除文件** @param path 文件地址* @param ip* @param port* @param uname* @param pwd* @return* @throws IOException*/public static Boolean deleteFile(String path, String ip, int port, String uname, String pwd) {Boolean flag = false;FTPClient ftpClient = new FTPClient();try {// 获取FTP客户端ftpClient = connectFTP(ip, port, uname, pwd);//删除if (ftpClient != null) {flag = ftpClient.deleteFile(path);log.info("您的文件【{}】删除成功。", path);}} catch (IOException e) {log.error("FTP删除文件时出错", e);throw new BusinessException("sys.file.delete.fail");} finally {closeFTP(ftpClient);}return flag;}/*** 删除目录** @param path目录地址* @param ftpClient FTP客户端* @return* @throws IOException*/public static Boolean deleteDirectory(String path, FTPClient ftpClient) {Boolean flag = false;try {//删除if (ftpClient != null) {flag = ftpClient.removeDirectory(path);log.info("您的目录【{}】删除成功。", path);}} catch (IOException e) {log.error("FTP删除目录时出错", e);throw new BusinessException("sys.file.delete.fail");} finally {closeFTP(ftpClient);}return flag;}/*** 删除目录** @param path 目录地址* @param ip* @param port* @param uname* @param pwd* @return* @throws IOException*/public static Boolean deleteDirectory(String path, String ip, int port, String uname, String pwd) {Boolean flag = false;FTPClient ftpClient = new FTPClient();try {// 获取FTP客户端ftpClient = connectFTP(ip, port, uname, pwd);//删除if (ftpClient != null) {flag = ftpClient.removeDirectory(path);log.info("您的目录【{}】删除成功。", path);}} catch (IOException e) {log.error("FTP删除目录时出错", e);throw new BusinessException("sys.file.delete.fail");} finally {closeFTP(ftpClient);}return flag;}/*** 从ftp上下载** @param output输出流* @param remoteFile 文件路径* @param ftpClient FTP客户端*/public static void download(OutputStream output, String remoteFile, FTPClient ftpClient) {try {ftpClient.enterLocalPassiveMode();ftpClient.retrieveFile(remoteFile, output);output.flush();log.info("您的文件【{}】下载成功。", remoteFile);} catch (Exception e) {log.error("下载文件出错：", e);} finally {IOUtils.closeQuietly(output);closeFTP(ftpClient);}}/*** 从ftp上下载** @param output输出流* @param remoteFile 文件路径* @param ip* @param port* @param uname* @param pwd*/public static void download(OutputStream output, String remoteFile, String ip, int port, String uname, String pwd) {FTPClient ftpClient = new FTPClient();try {// 获取FTP客户端ftpClient = connectFTP(ip, port, uname, pwd);ftpClient.enterLocalPassiveMode();ftpClient.retrieveFile(remoteFile, output);output.flush();log.info("您的文件【{}】下载成功。", remoteFile);} catch (Exception e) {log.error("下载文件出错：", e);} finally {IOUtils.closeQuietly(output);closeFTP(ftpClient);}}/*** 连接FTP服务器** @param ip* @param port* @param uname* @param pwd* @return* @throws IOException*/public static FTPClient connectFTP(String ip, int port, String uname, String pwd) throws IOException {FTPClient ftpClient = new FTPClient();// 优先设置编码格式，避免中文乱码ftpClient.setAutodetectUTF8(true);ftpClient.setCharset(CharsetUtil.UTF_8);ftpClient.setControlEncoding(CharsetUtil.UTF_8.name());ftpClient.connect(ip, port);boolean login = ftpClient.login(uname, pwd);if (!login) {throw new BusinessException("ftp连接失败，请检查配置");}ftpClient.enterLocalPassiveMode();ftpClient.setFileType(FTP.BINARY_FILE_TYPE);ftpClient.setBufferSize(DEFAULT_BUFFER_SIZE);return ftpClient;}/*** 关闭连接** @param ftpClient*/public static void closeFTP(FTPClient ftpClient) {if (ftpClient != null) {try {ftpClient.disconnect();} catch (IOException e) {log.error("关闭FTP连接出错", e);throw new BusinessException("sys.file.fail");}}}/*** 校验路径是否存在，不存在则新建** @param ftpClient* @param uploadPath* @throws IOException*/private static void checkFTPPath(FTPClient ftpClient, String uploadPath) throws IOException {//判断路径是否存在，不存在则新建if (uploadPath != null) {String[] paths = uploadPath.split("/");StringBuffer tempPath = new StringBuffer();for (String path : paths) {if ((path != null) && (!"".equals(path.trim()))) {String temp = tempPath.append("/").append(path.trim()).toString();if ((!ftpClient.changeWorkingDirectory(temp)) && (ftpClient.makeDirectory(temp))) {ftpClient.changeWorkingDirectory(temp);}}}}}}
