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());      }    } }