关闭没有 DataOutputStream & Socket 的 CipherOutputStream

Question

我正在与 Cipher 合作，其中在基础 socket 和 dataoutputstream 上保持连接。现在根据 CipherOutputStream 文档，为了让最后一个块从加密器中出来，我们需要调用 close()。因此，将它与 try-with-resource 一起使用也会关闭我不想要的底层流，因为我需要它们进行进一步的操作。

那么有没有什么方法或实现可以帮助我在没有 dataoutputstream 和 socket 的情况下关闭 cipheroutputstream？我听说过 FilterOutputStream 但我不知道如何使用它们。

我的代码：

public class ClientHandler implements Runnable {
Socket msock;
DataInputStream dis;
DataOutputStream dos;
String ip;
private miniClientHandler(Socket msock) {
            this.msock = msock;
        }
@Override
public void run() {
    try {
        dis = new DataInputStream(msock.getInputStream());
        dos = new DataOutputStream(msock.getOutputStream());

        ip = msock.getInetAddress().getHostAddress();

        String msg = dis.readLine();
        System.out.println(msg);

        if (msg.equals("Download")) {

                    String file2dl = dis.readLine(); //2
                    File file = new File(sharedDirectory.toString() + "\" + file2dl);
                    dos.writeLong(file.length()); //3+

                    //AES-128 bit key initialization.
                    byte[] keyvalue = "AES128BitPasswd".getBytes();
                    SecretKey key = new SecretKeySpec(keyvalue, "AES");

                    //Initialize the Cipher.
                    Cipher encCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
                    encCipher.init(Cipher.ENCRYPT_MODE, key);

                    //Get the IV from cipher.
                    IvParameterSpec spec = null;
                    try {
                        spec = encCipher.getParameters().getParameterSpec(IvParameterSpec.class);
                    } catch (InvalidParameterSpecException ex) {
                        Logger.getLogger(PeersController.class.getName()).log(Level.SEVERE, null, ex);
                    }

                    byte[] iv = spec.getIV();

                    dos.write(iv, 0, iv.length); //4+

                    //Encryption Mechanism.
                    try (FileInputStream fis = new FileInputStream(file)) {
                        try (CipherOutputStream cos = new CipherOutputStream(dos, encCipher)) {
                            int read;
                            byte[] buffer = new byte[1024 * 1024];
                            while ((read = fis.read(buffer)) != -1) {
                                cos.write(buffer, 0, read); //5+ due to dos as underlying parameter of cos.
                            }
                        }
                    }

                    String message = dis.readLine();
                    System.out.println(message);
                    if (message.equals("Fetching Done")) {
                        System.out.println("Fetching Done!");
                    } else if (message.equals("Fetching Drop")) {
                        System.out.println("Fetching Denied!");
                    }
                }
            } catch (IOException | NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException e) {
                System.out.println(e.getMessage());
            }
        }

    }

现在因为 cos 被包裹在 try-with-resource 中，当 while 循环结束时，它关闭流和底层 dos 流，后者进一步包裹 msock 导致整个套接字关闭和我剩余的代码没用了。

剩余代码：

    String message = dis.readLine();
    System.out.println(message);
    if (message.equals("Fetching Done")) {
        System.out.println("Fetching Done!");
     } else if (message.equals("Fetching Drop")) {
                 System.out.println("Fetching Denied!");
     }

Answer 1

在@EJP 建议的帮助下，我设法自己解决了我的问题，通过 update() & doFinal().

创建了我自己的 Cipher 对象 代码：

//Encryption Mechanism.
  try (FileInputStream fis = new FileInputStream(file)) {

       byte[] buffer = new byte[1024 * 1024];
       byte[] cipherBlock = new byte[encCipher.getOutputSize(buffer.length)];
       int cipherBytes;
       int read;
       while ((read = fis.read(buffer)) != -1) {
              cipherBytes = encCipher.update(buffer, 0, read, cipherBlock);
              dos.write(cipherBlock, 0, cipherBytes);
        }
        cipherBytes = encCipher.doFinal(cipherBlock, 0); //let out the last block out of the encryptor.
        dos.write(cipherBlock, 0, cipherBytes);
     } catch (ShortBufferException | IllegalBlockSizeException | BadPaddingException ex) {
              Logger.getLogger(PeersController.class.getName()).log(Level.SEVERE, null, ex);
       }

关闭没有 DataOutputStream & Socket 的 CipherOutputStream

Close CipherOutputStream without DataOutputStream & Socket

java

sockets

encryption

dataoutputstream