基於Apache FTP實現文件上傳下載工具，上傳文件時需要考慮以下問題（實例是續傳功能）：
（1）、 FTP服務器是否存在改目錄，如果不存在目錄則需要創建目錄。
（2）、判斷上傳文件是否已經存在，如果存在是需要刪除後再上傳還是續傳。
1、上傳或下載狀態的枚舉類：
package com.scengine.wtms.utils.ftp; public enum UploadStatus { File_Exits(0), Create_Directory_Success(1), Create_Directory_Fail(2), Upload_From_Break_Success(3), Upload_From_Break_Faild(4), Download_From_Break_Success(5), Download_From_Break_Faild(6), Upload_New_File_Success(7), Upload_New_File_Failed(8), Delete_Remote_Success(9), Delete_Remote_Faild(10),Remote_Bigger_Local(11),Remote_smaller_locall(12); private int status; public int getStatus() { return status; } public void setStatus(int status) { this.status = status; } UploadStatus(int status) { this.status = status; } }2、工具類代碼：
package com.scengine.wtms.utils.ftp; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.PrintWriter; import org.apache.commons.net.PrintCommandListener; 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; public class ContinueFTP { private FTPClient ftpClient = new FTPClient(); /** * 對象構造設置將過程中使用到的命令輸出到控制台*/ public ContinueFTP() { this.ftpClient.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out))); } /** * * java編程中用於連接到FTP服務器* * @param hostname * 主機名* * @param port * 端口* * @param username * 用戶名* * @param password * 密碼* * @return 是否連接成功* * @throws IOException */ public boolean connect(String hostname, int port, String username, String password) throws IOException { ftpClient.connect(hostname, port); if (FTPReply.isPositiveCompletion(ftpClient.getReplyCode())) { if (ftpClient.login(username, password)) { return true; } } disconnect(); return false; } /** * * 從FTP服務器上下載文件* * @param remote * 遠程文件路徑* * @param local * 本地文件路徑* * @return 是否成功* * @throws IOException */ @SuppressWarnings("resource") public boolean download(String remote, String local) throws IOException { ftpClient.enterLocalPassiveMode(); ftpClient.setFileType(FTP.BINARY_FILE_TYPE); boolean result; File f = new File(local); FTPFile[] files = ftpClient.listFiles(remote); if (files.length != 1) { System.out.println("遠程文件不唯一"); return false; } long lRemoteSize = files[0].getSize(); if (f.exists()) { OutputStream out = new FileOutputStream(f, true); System.out.println("本地文件大小為:" + f.length()); if (f.length() >= lRemoteSize) { System.out.println("本地文件大小大於遠程文件大小，下載中止"); return false; } ftpClient.setRestartOffset(f.length()); result = ftpClient.retrieveFile(remote, out); out.close(); } else { OutputStream out = new FileOutputStream(f); result = ftpClient.retrieveFile(remote, out); out.close(); } return result; } /** * * 上傳文件到FTP服務器，支持斷點續傳* * @param local * 本地文件名稱，絕對路徑* * @param remote * 遠程文件路徑，使用/home/directory1/subdirectory/file.ext * 按照Linux上的路徑指定方式，支持多級目錄嵌套，支持遞歸創建不存在的目錄結構* * @return 上傳結果* * @throws IOException */ @SuppressWarnings("resource") public UploadStatus upload(String local, String remote) throws IOException { // 設置PassiveMode傳輸ftpClient.enterLocalPassiveMode(); // 設置以二進制流的方式傳輸ftpClient.setFileType(FTP.BINARY_FILE_TYPE); UploadStatus result; // 對遠程目錄的處理String remoteFileName = remote; if (remote.contains("/")) { remoteFileName = remote.substring(remote.lastIndexOf("/") + 1); String directory = remote.substring(0, remote.lastIndexOf("/") + 1); if (!directory.equalsIgnoreCase("/") && !ftpClient.changeWorkingDirectory(directory)) { // 如果遠程目錄不存在，則遞歸創建遠程服務器目錄int start = 0; int end = 0; if (directory.startsWith("/")) { start = 1; } else { start = 0; } end = directory.indexOf("/", start); while (true) { String subDirectory = remote.substring(start, end); if (!ftpClient.changeWorkingDirectory(subDirectory)) { if (ftpClient.makeDirectory(subDirectory)) { ftpClient.changeWorkingDirectory(subDirectory); } else { System.out.println("創建目錄失敗"); return UploadStatus.Create_Directory_Fail; } } start = end + 1; end = directory.indexOf("/", start); // 檢查所有目錄是否創建完畢if (end <= start) { break; } } } } // 檢查遠程是否存在文件FTPFile[] files = ftpClient.listFiles(remoteFileName); if (files.length == 1) { long remoteSize = files[0].getSize(); File f = new File(local); long localSize = f.length(); if (remoteSize == localSize) { return UploadStatus.File_Exits; } else if (remoteSize > localSize) { return UploadStatus.Remote_Bigger_Local; } // 嘗試移動文件內讀取指針,實現斷點續傳InputStream is = new FileInputStream(f); if (is.skip(remoteSize) == remoteSize) { ftpClient.setRestartOffset(remoteSize); if (ftpClient.storeFile(remote, is)) { return UploadStatus.Upload_From_Break_Success; } } // 如果斷點續傳沒有成功，則刪除服務器上文件，重新上傳if (!ftpClient.deleteFile(remoteFileName)) { return UploadStatus.Delete_Remote_Faild; } is = new FileInputStream(f); if (ftpClient.storeFile(remote, is)) { result = UploadStatus.Upload_New_File_Success; } else { result = UploadStatus.Upload_New_File_Failed; } is.close(); } else { InputStream is = new FileInputStream(local); if (ftpClient.storeFile(remoteFileName, is)) { result = UploadStatus.Upload_New_File_Success; } else { result = UploadStatus.Upload_New_File_Failed; } is.close(); } return result; } /** * * 斷開與遠程服務器的連接* * @throws IOException */ public void disconnect() throws IOException { if (ftpClient.isConnected()) { ftpClient.disconnect(); } } public static void main(String[] args) { ContinueFTP myFtp = new ContinueFTP(); try { myFtp.connect("192.168.1.200", 21, "duser", "HTPDuserXP32"); System.out.println(myFtp.upload("C://Users//Administrator//Desktop//swing.drawer.jar", "/jars/swing.drawer.jar")); myFtp.disconnect(); } catch (IOException e) { System.out.println("連接FTP出錯：" + e.getMessage()); } } }以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。