本文實例講述了JAVA實現FTP斷點上傳的方法。分享給大家供大家參考。具體分析如下：
這里主要使用apache中的net包來實現。網址http://commons.apache.org/net/。具體包的下載和API文檔請看官網。 斷點上傳就是在上傳的過程中設置傳輸的起始位置。并設置二進制傳輸。
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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(); public ContinueFTP(){ //設置將過程中使用到的命令輸出到控制臺 this.ftpClient.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out))); } /** * java編程中用于連接到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 */ 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("本地文件大小大于遠程文件大小，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 */ 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("192.168.21.171", 21, "test", "test"); System.out.println(myFtp.upload("E:\\VP6.flv", "/MIS/video/VP6.flv")); myFtp.disconnect(); } catch (IOException e) { System.out.println("連接FTP出錯："+e.getMessage()); } } } |
希望本文所述對大家的java程序設計有所幫助。
