这个写法我试过可以用，项目中用到的，记录一下。
代码：
1 import org.apache.commons.net.ftp.FTPClient; 2 import org.apache.commons.net.ftp.FTPFile; 3 import org.apache.commons.net.ftp.FTPReply; 4 5 import java.io.*; 6 import java.net.MalformedURLException; 7 8 public class FtpUtils { 9 //ftp服务器地址 10 public String hostname = "192.168.1.249"; 11 //ftp服务器端口号默认为21 12 public Integer port = 21 ; 13 //ftp登录账号 14 public String username = "root"; 15 //ftp登录密码 16 public String password = "123"; 17 18 public FTPClient ftpClient = null; 19 20 /** 21 * 初始化ftp服务器 22 */ 23 public void initFtpClient() { 24 ftpClient = new FTPClient(); 25 ftpClient.setControlEncoding("utf-8"); 26 try { 27 System.out.println("connecting...ftp服务器:"+this.hostname+":"+this.port); 28 ftpClient.connect(hostname, port); //连接ftp服务器 29 ftpClient.login(username, password); //登录ftp服务器 30 int replyCode = ftpClient.getReplyCode(); //是否成功登录服务器 31 if(!FTPReply.isPositiveCompletion(replyCode)){ 32 System.out.println("connect failed...ftp服务器:"+this.hostname+":"+this.port); 33 } 34 System.out.println("connect successfu...ftp服务器:"+this.hostname+":"+this.port); 35 }catch (MalformedURLException e) { 36 e.printStackTrace(); 37 }catch (IOException e) { 38 e.printStackTrace(); 39 } 40 } 41 42 /** 43 * 上传文件 44 * @param pathname ftp服务保存地址 45 * @param fileName 上传到ftp的文件名 46 * @param originfilename 待上传文件的名称（绝对地址） * 47 * @return 48 */ 49 public boolean uploadFile( String pathname, String fileName,String originfilename){ 50 boolean flag = false; 51 InputStream inputStream = null; 52 try{ 53 System.out.println("开始上传文件"); 54 inputStream = new FileInputStream(new File(originfilename)); 55 initFtpClient(); 56 ftpClient.setFileType(ftpClient.BINARY_FILE_TYPE); 57 CreateDirecroty(pathname); 58 ftpClient.makeDirectory(pathname); 59 ftpClient.changeWorkingDirectory(pathname); 60 ftpClient.storeFile(fileName, inputStream); 61 inputStream.close(); 62 ftpClient.logout(); 63 flag = true; 64 System.out.println("上传文件成功"); 65 }catch (Exception e) { 66 System.out.println("上传文件失败"); 67 e.printStackTrace(); 68 }finally{ 69 if(ftpClient.isConnected()){ 70 try{ 71 ftpClient.disconnect(); 72 }catch(IOException e){ 73 e.printStackTrace(); 74 } 75 } 76 if(null != inputStream){ 77 try { 78 inputStream.close(); 79 } catch (IOException e) { 80 e.printStackTrace(); 81 } 82 } 83 } 84 return true; 85 } 86 /** 87 * 上传文件 88 * @param pathname ftp服务保存地址 89 * @param fileName 上传到ftp的文件名 90 * @param inputStream 输入文件流 91 * @return 92 */ 93 public boolean uploadFile( String pathname, String fileName,InputStream inputStream){ 94 boolean flag = false; 95 try{ 96 System.out.println("开始上传文件"); 97 initFtpClient(); 98 ftpClient.setFileType(ftpClient.BINARY_FILE_TYPE); 99 CreateDirecroty(pathname); 100 ftpClient.makeDirectory(pathname); 101 ftpClient.changeWorkingDirectory(pathname); 102 ftpClient.storeFile(fileName, inputStream); 103 inputStream.close(); 104 ftpClient.logout(); 105 flag = true; 106 System.out.println("上传文件成功"); 107 }catch (Exception e) { 108 System.out.println("上传文件失败"); 109 e.printStackTrace(); 110 }finally{ 111 if(ftpClient.isConnected()){ 112 try{ 113 ftpClient.disconnect(); 114 }catch(IOException e){ 115 e.printStackTrace(); 116 } 117 } 118 if(null != inputStream){ 119 try { 120 inputStream.close(); 121 } catch (IOException e) { 122 e.printStackTrace(); 123 } 124 } 125 } 126 return true; 127 } 128 //改变目录路径 129 public boolean changeWorkingDirectory(String directory) { 130 boolean flag = true; 131 try { 132 flag = ftpClient.changeWorkingDirectory(directory); 133 if (flag) { 134 System.out.println("进入文件夹" + directory + " 成功！"); 135 136 } else { 137 System.out.println("进入文件夹" + directory + " 失败！开始创建文件夹"); 138 } 139 } catch (IOException ioe) { 140 ioe.printStackTrace(); 141 } 142 return flag; 143 } 144 145 //创建多层目录文件，如果有ftp服务器已存在该文件，则不创建，如果无，则创建 146 public boolean CreateDirecroty(String remote) throws IOException { 147 boolean success = true; 148 String directory = remote + "/"; 149 // 如果远程目录不存在，则递归创建远程服务器目录 150 if (!directory.equalsIgnoreCase("/") && !changeWorkingDirectory(new String(directory))) { 151 int start = 0; 152 int end = 0; 153 if (directory.startsWith("/")) { 154 start = 1; 155 } else { 156 start = 0; 157 } 158 end = directory.indexOf("/", start); 159 String path = ""; 160 String paths = ""; 161 while (true) { 162 String subDirectory = new String(remote.substring(start, end).getBytes("GBK"), "iso-8859-1"); 163 path = path + "/" + subDirectory; 164 if (!existFile(path)) { 165 if (makeDirectory(subDirectory)) { 166 changeWorkingDirectory(subDirectory); 167 } else { 168 System.out.println("创建目录[" + subDirectory + "]失败"); 169 changeWorkingDirectory(subDirectory); 170 } 171 } else { 172 changeWorkingDirectory(subDirectory); 173 } 174 175 paths = paths + "/" + subDirectory; 176 start = end + 1; 177 end = directory.indexOf("/", start); 178 // 检查所有目录是否创建完毕 179 if (end <= start) { 180 break; 181 } 182 } 183 } 184 return success; 185 } 186 187 //判断ftp服务器文件是否存在 188 public boolean existFile(String path) throws IOException { 189 boolean flag = false; 190 FTPFile[] ftpFileArr = ftpClient.listFiles(path); 191 if (ftpFileArr.length > 0) { 192 flag = true; 193 } 194 return flag; 195 } 196 //创建目录 197 public boolean makeDirectory(String dir) { 198 boolean flag = true; 199 try { 200 flag = ftpClient.makeDirectory(dir); 201 if (flag) { 202 System.out.println("创建文件夹" + dir + " 成功！"); 203 204 } else { 205 System.out.println("创建文件夹" + dir + " 失败！"); 206 } 207 } catch (Exception e) { 208 e.printStackTrace(); 209 } 210 return flag; 211 } 212 213 /** * 下载文件 * 214 * @param pathname FTP服务器文件目录 * 215 * @param filename 文件名称 * 216 * @param localpath 下载后的文件路径 * 217 * @return */ 218 public boolean downloadFile(String pathname, String filename, String localpath){ 219 boolean flag = false; 220 OutputStream os=null; 221 try { 222 System.out.println("开始下载文件"); 223 initFtpClient(); 224 //切换FTP目录 225 ftpClient.changeWorkingDirectory(pathname); 226 FTPFile[] ftpFiles = ftpClient.listFiles(); 227 for(FTPFile file : ftpFiles){ 228 if(filename.equalsIgnoreCase(file.getName())){ 229 File localFile = new File(localpath + "/" + file.getName()); 230 os = new FileOutputStream(localFile); 231 ftpClient.retrieveFile(file.getName(), os); 232 os.close(); 233 } 234 } 235 ftpClient.logout(); 236 flag = true; 237 System.out.println("下载文件成功"); 238 } catch (Exception e) { 239 System.out.println("下载文件失败"); 240 e.printStackTrace(); 241 } finally{ 242 if(ftpClient.isConnected()){ 243 try{ 244 ftpClient.disconnect(); 245 }catch(IOException e){ 246 e.printStackTrace(); 247 } 248 } 249 if(null != os){ 250 try { 251 os.close(); 252 } catch (IOException e) { 253 e.printStackTrace(); 254 } 255 } 256 } 257 return flag; 258 } 259 260 /** * 删除文件 * 261 * @param pathname FTP服务器保存目录 * 262 * @param filename 要删除的文件名称 * 263 * @return */ 264 public boolean deleteFile(String pathname, String filename){ 265 boolean flag = false; 266 try { 267 System.out.println("开始删除文件"); 268 initFtpClient(); 269 //切换FTP目录 270 ftpClient.changeWorkingDirectory(pathname); 271 ftpClient.dele(filename); 272 ftpClient.logout(); 273 flag = true; 274 System.out.println("删除文件成功"); 275 } catch (Exception e) { 276 System.out.println("删除文件失败"); 277 e.printStackTrace(); 278 } finally { 279 if(ftpClient.isConnected()){ 280 try{ 281 ftpClient.disconnect(); 282 }catch(IOException e){ 283 e.printStackTrace(); 284 } 285 } 286 } 287 return flag; 288 } 289 290 public static void main(String[] args) { 291 FtpUtils ftp =new FtpUtils(); 292 //ftp.uploadFile("ftpFile/data", "123.docx", "E://123.docx"); 293 //ftp.downloadFile("ftpFile/data", "123.docx", "F://"); 294 ftp.deleteFile("ftpFile/data", "123.docx"); 295 System.out.println("ok"); 296 } 297 }