Spring集成TCP服务器无法接收消息

Question

我正在尝试创建一个TCP服务器，它从外部程序接受端口5002上的消息。但是，它没有从外部程序接收消息。

@Bean
public TcpReceivingChannelAdapter inbound(AbstractServerConnectionFactory cf) {
   TcpReceivingChannelAdapter adapter = new TcpReceivingChannelAdapter();
   adapter.setConnectionFactory(cf);
   adapter.setOutputChannel(tcpIn());
   return adapter;
 }

@Bean
public MessageChannel tcpIn() {
    return new DirectChannel();
}

@Bean
@Transformer(inputChannel = "tcpIn", outputChannel = "serviceChannel")
public ObjectToStringTransformer transformer() {
    return new ObjectToStringTransformer();
}

@ServiceActivator(inputChannel = "serviceChannel")
public void messageToService(String in) {
    // Message received
}

@Bean
public AbstractServerConnectionFactory serverConnectionFactory() {
    TcpNetServerConnectionFactory tcpNetServerConnectionFactory = new TcpNetServerConnectionFactory(5002);
    tcpNetServerConnectionFactory.setSoTimeout(5000);
    tcpNetServerConnectionFactory.setMapper(new TimeoutMapper());
    return tcpNetServerConnectionFactory;
}

为了验证我的TCP服务器是否正常工作，我使用了telnet，并且程序确实得到了“hello”文本。

telnet 192.168.1.2 5002
Trying 192.168.1.2...
Connected to 192.168.1.2.
Escape character is '^]'.
hello

设置wireshark我可以看到计算机正在从端口5002上的外部程序（我期待的）接收消息。为什么我的程序无法接收这些消息？

最终解决方案更新：

由于有效载荷没有停止线，我必须按照@Artem Bilan的描述实现我自己的反序列化器。我使用'〜'字符表示来自客户端的行尾。

@Bean
public AbstractServerConnectionFactory serverConnectionFactory() {
    TcpNetServerConnectionFactory tcpNetServerConnectionFactory = new TcpNetServerConnectionFactory(tcpPort);
    tcpNetServerConnectionFactory.setSoTimeout(0);
  tcpNetServerConnectionFactory.setDeserializer(endOfLineSerializer());
    tcpNetServerConnectionFactory.setSerializer(endOfLineSerializer());
    tcpNetServerConnectionFactory.setMapper(new TimeoutMapper());
    return tcpNetServerConnectionFactory;
}

我实施的示例序列化器：

public class EndOfLineSerializer extends AbstractPooledBufferByteArraySerializer {

private static final char MANUAL_STOP_LINE = '~';
private static final char AUTO_STOP_LINE = '\t';
private static final byte[] CRLF = "\r\n".getBytes();

/**
 * Reads the data in the inputStream to a byte[]. Data must be terminated
 * by a single byte. Throws a {@link SoftEndOfStreamException} if the stream
 * is closed immediately after the terminator (i.e. no data is in the process of
 * being read).
 */
@Override
protected byte[] doDeserialize(InputStream inputStream, byte[] buffer) throws IOException {
    int n = 0;
    int bite;

    try {
        while (true) {

            try {
                bite = inputStream.read();
            } catch (SocketTimeoutException e) {
                bite = -1;
            }

            if (bite < 0) {
                // Payload complete
                break;
            }

            if ((n > 0 && bite == '\n' && buffer[n - 1] == '\r') || bite == this.MANUAL_STOP_LINE || bite == this.AUTO_STOP_LINE) {
                break;
            }

            buffer[n++] = (byte) bite;
            if (n >= this.maxMessageSize) {
                throw new IOException("Terminator not found before max message length: " + this.maxMessageSize);
            }
        }
        return copyToSizedArray(buffer, n);
    } catch (IOException e) {
        publishEvent(e, buffer, n);
        throw e;
    } catch (RuntimeException e) {
        publishEvent(e, buffer, n);
        throw e;
    }
}

/**
 * Writes the byte[] to the stream and appends the CRLF.
 */
@Override
public void serialize(byte[] bytes, OutputStream outputStream) throws IOException {
    outputStream.write(bytes);
    outputStream.write(this.CRLF);
    }
}

Answer 1

TcpNetServerConnectionFactory默认情况下使用ByteArrayCrLfSerializer，其中这是消息分隔符：

private static final byte[] CRLF = "\r\n".getBytes();

因此，您应该确保您的客户端最后发送带有正确符号的消息。

您可以选择一堆开箱即用的序列化程序：

https://docs.spring.io/spring-integration/docs/5.0.3.RELEASE/reference/html/ip.html#tcp-connection-factories

或者您可以实现自己的Deserializer并注入serverConnectionFactory bean定义。

Answer 2

见the documentation;向下滚动到

  

TCP是一种流媒体协议;这意味着必须为通过TCP传输的数据提供一些结构，因此接收器可以将数据划分为离散消息。连接工厂配置为使用（反）序列化器在消息有效负载和通过TCP发送的位之间进行转换。这是通过分别为入站和出站消息提供解串器和串行器来实现的。提供了许多标准（de）序列化器。

并阅读标准反序列化器。使用您的配置，标准反序列化程序正在等待终止\r\n（CRLF）。

Telnet附加CRLF，这就是它工作的原因。