我正在进行财务消息传递集成，如下所示：
服务器具有一个接口，用于侦听来自特定IP和端口上的客户端套接字的请求
服务器将每个请求的响应发送回客户端套接字
另外，服务器将请求发送到同一客户端套接字
以下是完美的工作方式：
客户端套接字（Java IO的Socket对象）成功将请求发送到服务器接口
客户端套接字成功收到每个请求的响应
try {
Socket clientSocket = new Socket("example.com", 8888);
BufferedWriter output = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));
output.write(data);
output.flush();
BufferedReader input = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
// Read responses or new request from input
} catch (IOException e) {
e.printStackTrace();
}
客户端套接字应该可以接收来自服务器的任何请求，就像接收来自同一服务器的响应一样。但是，当服务器向客户端套接字发起请求时，永远不会收到该请求。但是，我们可以在客户端环境中跟踪来自tcpdump的流量。
如何使客户端套接字监听服务器发出的请求，而不仅仅是响应？
更新资料
可能有助于阐明有关此集成的一些信息：
一种。在这种情况下，“服务器”是第三方系统，具有集成规则
b。我的客户端套接字将消息发布到服务器（上面）
C。我的实现侦听来自第三方系统服务器的响应和请求，方法是创建自己的服务器套接字（排除），或者使用与我一起发送的客户端套接字（我正在寻找的解决方案）
最佳答案
这是一个非常常见的错误，您在编写消息时没有在末尾写“ \ n”（结束行标识符），因此不会读取任何消息。要解决此问题，请在PrintWriter中使用println。
这会将一条线发送到另一个插座。
这是服务器的每客户端线程模型的示例
//create a new server socket with the port as a parameter, this will bind it to the specified port: 6000
ServerSocket server = new ServerSocket(6000);
System.out.println("Binded");
//create a while loop accepting sockets
while(true)
{
//accept a socket
Socket client = server.accept();
System.out.println("Client has connected");
//create a new thread for this socket
new Thread(() ->
{
try
{
/*
create a print writer so you can write a line, not only a message like BufferedWriter does,
if for some reason you still want to use BufferedWriter use
writer.write(message + "\n");
*/
PrintWriter writer = new PrintWriter(new OutputStreamWriter(client.getOutputStream()));
//Create a new reader
BufferedReader reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
System.out.println("Waiting for requests...");
//create a while loop reading requests (lines)
String request;
while((request = reader.readLine()) != null)
{
System.out.println("Received message: " + request);
//here find the correct response and return it, I just sent a message, replace it with the correct response
writer.println("Hello there! How are you today?");
//flush, flushing will write the data to the client
writer.flush();
}
} catch(IOException e)
{
//print an exception if it occurred, if an exception occurrs its most likely just a disconnection exception
e.printStackTrace();
}
}).start();
}
这是一个客户的例子
//connect to the server at "localhost" on port 6000
Socket client = new Socket("localhost", 6000);
System.out.println("Connected");
/*
create a print writer so you can write a line, not only a message like BufferedWriter does,
if for some reason you still want to use BufferedWriter use
writer.write(message + "\n");
*/
PrintWriter writer = new PrintWriter(new OutputStreamWriter(client.getOutputStream()));
//Create a new reader
BufferedReader reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
//write a request
writer.println("Hi there!");
//flush, flushing will write the data to the server
writer.flush();
System.out.println("Written");
System.out.println("Waiting for responses...");
//create a while loop reading responses (lines)
//you may want to do this while loop in another thread
String response;
while((response = reader.readLine()) != null)
{
System.out.println("Received response: " + response);
}
另外，如果这与财务信息有关，我建议使用TLS (SSL)。
您不必担心Java已经实现并使其易于使用，这是服务器的示例
//create a new SSL server socket with the port as a parameter, this will bind it to the specified port: 6000
//you create it by getting the default SSLServerSocketFactory which will create a new SSLServerSocket
//you need to cast it since it actually returns ServerSocket but SSLServerSocket extends ServerSocket and this returns SSLServerSocket so it is safe
SSLServerSocket server = (SSLServerSocket) SSLServerSocketFactory.getDefault().createServerSocket(6000);
System.out.println("Binded");
//set the enabled ciphersuites, until you buy a certificate set only to ciphersuites with "anon" more info on ciphersuites on https://en.wikipedia.org/wiki/Cipher_suite
server.setEnabledCipherSuites(new String[]{"TLS_ECDH_anon_WITH_AES_256_CBC_SHA"});
//create a while loop accepting sockets
while(true)
{
//accept a socket a SSLSocket
SSLSocket client = (SSLSocket) server.accept();
System.out.println("Client has connected");
//create a new thread for this socket
new Thread(() ->
{
try
{
//begin a handshake more info about handshakes in https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_7.1.0/com.ibm.mq.doc/sy10660_.htm
client.startHandshake();
/*
create a print writer so you can write a line, not only a message like BufferedWriter does,
if for some reason you still want to use BufferedWriter use
writer.write(message + "\n");
*/
PrintWriter writer = new PrintWriter(new OutputStreamWriter(client.getOutputStream()));
//Create a new reader
BufferedReader reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
System.out.println("Waiting for requests...");
//create a while loop reading requests (lines)
String request;
while((request = reader.readLine()) != null)
{
System.out.println("Received message: " + request);
//here find the correct response and return it, I just sent a message, replace it with the correct response
writer.println("Hello there! How are you today?");
//flush, flushing will write the data to the client
writer.flush();
}
} catch(IOException e)
{
//print an exception if it occurred, if an exception occurrs its most likely just a disconnection exception
e.printStackTrace();
}
}).start();
}
这是一个客户的例子
//connect to the server at "localhost" on port 6000
//you create a SSLSocket by getting the default SSLSocketFactory which will create a new SSLSocket
//you need to cast it since it actually returns Socket but SSLSocket extends Socket and this returns SSLSocket so it is safe
SSLSocket client = (SSLSocket) SSLSocketFactory.getDefault().createSocket("localhost", 6000);
System.out.println("Connected");
//set the enabled ciphersuites to everything supported so the server can decide the ciphersuite, you can modify this to specified ciphersuites
client.setEnabledCipherSuites(client.getSupportedCipherSuites());
//begin a handshake more info about handshakes in https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_7.1.0/com.ibm.mq.doc/sy10660_.htm
client.startHandshake();
/*
create a print writer so you can write a line, not only a message like BufferedWriter does,
if for some reason you still want to use BufferedWriter use
writer.write(message + "\n");
*/
PrintWriter writer = new PrintWriter(new OutputStreamWriter(client.getOutputStream()));
//Create a new reader
BufferedReader reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
//write a request
writer.println("Hi there!");
//flush, flushing will write the data to the server
writer.flush();
System.out.println("Written");
System.out.println("Waiting for responses...");
//create a while loop reading responses (lines)
//you may want to do this while loop in another thread
String response;
while((response = reader.readLine()) != null)
{
System.out.println("Received response: " + response);
}