我正在编写基于客户端服务器的Java应用程序,我遇到了一个问题,因为它在客户端和服务器中构造ObjectInputStream时都会挂起。
客户端:
Socket socket = new Socket("localhost", 9999);
outCiph = new CipherOutputStream(socket.getOutputStream(), AES.getEncryptCipher("key"));
out = new ObjectOutputStream(outCiph);
inCiph = new CipherInputStream(socket.getInputStream(), AES.getDecryptCipher("key"));
in = new ObjectInputStream(inCiph);
try
{
String text = "test!";
out.writeObject(text);
out.flush();
if (out != null)
out.close();
if (in != null)
in.close();
}
catch (IOException ex)
{
System.err.println(ex.toString());
}
服务器:
ServerSocket serverSocket = new ServerSocket(9999);
Socket socket = serverSocket.accept();
outCiph = new CipherOutputStream(socket.getOutputStream(), AES.getEncryptCipher("key"));
out = new ObjectOutputStream(outCiph);
inCiph = new CipherInputStream(socket.getInputStream(), AES.getDecryptCipher("key"));
in = new ObjectInputStream(inCiph);
try
{
String rec = (String) in.readObject();
System.out.println("Received from client: " + rec);
if (out != null)
out.close();
if (in != null)
in.close();
}
catch (IOException ex)
{
System.err.println(ex.toString() + " in start()");
}
catch (ClassNotFoundException ex)
{
System.err.println(ex.toString());
}
AES:
// I'm not author of generateKey method so I've no idea if is it correct
private static byte[] generateKey(String pass) throws UnsupportedEncodingException, NoSuchAlgorithmException
{
MessageDigest sha = MessageDigest.getInstance("SHA-256");
byte[] passBytes = pass.getBytes("ASCII");
byte[] sha256Bytes = sha.digest(passBytes);
byte[] key = new byte[16];
int j = 0;
for (int i = 0; i < sha256Bytes.length; i++)
{
if (i % 2 == 0)
{
key[j] = sha256Bytes[i];
j++;
}
}
return key;
}
public static Cipher getEncryptCipher(String pass)
{
try
{
SecretKeySpec skeySpec = new SecretKeySpec(generateKey(pass), "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
return cipher;
}
catch (Exception ex) // just for clarity
{
Logger.getLogger(AES.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
public static Cipher getDecryptCipher(String pass)
{
try
{
SecretKeySpec skeySpec = new SecretKeySpec(generateKey(pass), "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
return cipher;
}
catch (Exception ex) // just for clarity
{
Logger.getLogger(AES.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
当我不使用CipherInput / OutputStream时,一切正常,所以问题与CipherInput / OutputStream有某种关系。
答案 0 :(得分:1)
只有在发送所有信息后才需要创建ObjectInputStream,因为ObjectInputStream的构造函数因为需要读取头而阻塞。
通常,所有字节都是由ObjectOutputStream写的,但是现在CipherOutputStream一直等到它有一个完整的16字节块(在AES的情况下),然后才发送(最后一部分)头。也许流式密码模式(CTR或GCM)中的AES在这里会更有用,因为它使用每字节加密,并且能够直接发送每个字节。