Java - FTP程序在传输过程中损坏文件(Java - FTP program corrupting file during transfer)

 我使用套接字创建了一个基本的客户端服务器FTP程序，但由于某些原因，文件在传输过程中被破坏了。 在下面的例子中，我正在从客户端将文件推送到服务器。 它几乎可以工作，因为一些文件（如.png）传输和打开罚款，但其他文件（.docx）则不然。 我传输的任何文件都与我发送的MD5不同。 
 
 客户代码： 
 
File file = null;
            FTPDataBlock transferBlock;
            int numBytesRead = 0;
            int blockNumber = 1;
            int blockSize = 1024;
            byte[] block = new byte[blockSize];
            fc = new JFileChooser();

            // select file to upload
            int returnVal = fc.showOpenDialog(Client.this);
            if (returnVal == JFileChooser.APPROVE_OPTION) {
                file = fc.getSelectedFile();

                try {
                    // get total number of blocks and send to server
                    int totalNumBlocks = (int)Math.ceil((file.length()*1.0) / blockSize);
                    System.out.println("File length is: " + file.length());
                    FTPCommand c = new FTPCommand("PUSH", Integer.toString(totalNumBlocks));
                    oos = new ObjectOutputStream(sock.getOutputStream());
                    oos.writeObject(c);
                    oos.flush();

                    // send to server block by block
                    FileInputStream fin = new FileInputStream(file);
                    while ((numBytesRead = fin.read(block)) != -1){
                        transferBlock = new FTPDataBlock(file.getName(), blockNumber, block);
                        blockNumber++;
                        System.out.println("Sending block " + transferBlock.getBlockNumber() + " of " + totalNumBlocks);
                        oos = new ObjectOutputStream(sock.getOutputStream());
                        oos.writeObject(transferBlock);
                        oos.flush();
                    }

                    fin.close();
                    System.out.println("PUSH Complete");

                    // get response from server
                    ois = new ObjectInputStream(sock.getInputStream());
                    FTPResponse response = (FTPResponse)ois.readObject();
                    statusArea.setText(response.getResponse());


                } catch (IOException | ClassNotFoundException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            }
 
 服务器代码： 
 
else if (cmd.getCommand().equals("PUSH")){
                    // get total number of file blocks
                    int totalNumBlocks = Integer.parseInt(cmd.getParameters());

                    // get first block
                    in = new ObjectInputStream(sock.getInputStream());
                    FTPDataBlock currentBlock = (FTPDataBlock)in.readObject();

                    // create file and write first block to file
                    File file = new File (workingDirectory + File.separator + currentBlock.getFilename());
                    FileOutputStream fOut = new FileOutputStream(file);
                    fOut.write(currentBlock.getData());
                    fOut.flush();

                    // get remaining blocks
                    while(currentBlock.getBlockNumber()+1 <= totalNumBlocks){
                        in = new ObjectInputStream(sock.getInputStream());
                        currentBlock = (FTPDataBlock)in.readObject();
                        fOut.write(currentBlock.getData());
                        fOut.flush();
                    }

                    fOut.close();

                    // send response
                    FTPResponse response = new FTPResponse("File Received OK");
                    out = new ObjectOutputStream(sock.getOutputStream());
                    out.writeObject(response);
                }
 
 FTPDataBlock类： 
 
public class FTPDataBlock implements Serializable{

    private static final long serialVersionUID = 1L;
    private String filename;
    private int blockNumber; // current block number
    private byte[] data;
    //constructors & accessors
}
 
 我确定这是我在这里失踪的小事。 有任何想法吗？ 

I've made a basic client server FTP program using sockets, but for some reason files are getting corrupted during the transfer. In the case below, I'm pushing a file to the server from the client. It almost works, since some files (such as a .png) transfer and open fine, but others (a .docx) don't. Any file that I transfer has a different MD5 to the one I sent.
 
Client code:
 
File file = null;
            FTPDataBlock transferBlock;
            int numBytesRead = 0;
            int blockNumber = 1;
            int blockSize = 1024;
            byte[] block = new byte[blockSize];
            fc = new JFileChooser();

            // select file to upload
            int returnVal = fc.showOpenDialog(Client.this);
            if (returnVal == JFileChooser.APPROVE_OPTION) {
                file = fc.getSelectedFile();

                try {
                    // get total number of blocks and send to server
                    int totalNumBlocks = (int)Math.ceil((file.length()*1.0) / blockSize);
                    System.out.println("File length is: " + file.length());
                    FTPCommand c = new FTPCommand("PUSH", Integer.toString(totalNumBlocks));
                    oos = new ObjectOutputStream(sock.getOutputStream());
                    oos.writeObject(c);
                    oos.flush();

                    // send to server block by block
                    FileInputStream fin = new FileInputStream(file);
                    while ((numBytesRead = fin.read(block)) != -1){
                        transferBlock = new FTPDataBlock(file.getName(), blockNumber, block);
                        blockNumber++;
                        System.out.println("Sending block " + transferBlock.getBlockNumber() + " of " + totalNumBlocks);
                        oos = new ObjectOutputStream(sock.getOutputStream());
                        oos.writeObject(transferBlock);
                        oos.flush();
                    }

                    fin.close();
                    System.out.println("PUSH Complete");

                    // get response from server
                    ois = new ObjectInputStream(sock.getInputStream());
                    FTPResponse response = (FTPResponse)ois.readObject();
                    statusArea.setText(response.getResponse());


                } catch (IOException | ClassNotFoundException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            }
 
Server Code:
 
else if (cmd.getCommand().equals("PUSH")){
                    // get total number of file blocks
                    int totalNumBlocks = Integer.parseInt(cmd.getParameters());

                    // get first block
                    in = new ObjectInputStream(sock.getInputStream());
                    FTPDataBlock currentBlock = (FTPDataBlock)in.readObject();

                    // create file and write first block to file
                    File file = new File (workingDirectory + File.separator + currentBlock.getFilename());
                    FileOutputStream fOut = new FileOutputStream(file);
                    fOut.write(currentBlock.getData());
                    fOut.flush();

                    // get remaining blocks
                    while(currentBlock.getBlockNumber()+1 <= totalNumBlocks){
                        in = new ObjectInputStream(sock.getInputStream());
                        currentBlock = (FTPDataBlock)in.readObject();
                        fOut.write(currentBlock.getData());
                        fOut.flush();
                    }

                    fOut.close();

                    // send response
                    FTPResponse response = new FTPResponse("File Received OK");
                    out = new ObjectOutputStream(sock.getOutputStream());
                    out.writeObject(response);
                }
 
FTPDataBlock class:
 
public class FTPDataBlock implements Serializable{

    private static final long serialVersionUID = 1L;
    private String filename;
    private int blockNumber; // current block number
    private byte[] data;
    //constructors & accessors
}
 
I'm sure it's something small that I'm missing here. Any ideas?

原文：https://stackoverflow.com/questions/21606473