JAVA實現FTP斷點上傳

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。

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());  
         }  
     }  
 }