如何从客户端关闭套接字通道，以便服务器引发java.nio.channels.ClosedChannelException

Question

I have an issue where a server(Apache Synapse) intermittently throws "java.nio.channels.ClosedChannelException".

java.nio.channels.ClosedChannelException
at sun.nio.ch.SocketChannelImpl.ensureWriteOpen(SocketChannelImpl.java:135)
at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:326)
at org.apache.http.impl.nio.reactor.SessionOutputBufferImpl.flush(SessionOutputBufferImpl.java:167)
at org.apache.http.impl.nio.DefaultNHttpServerConnection.produceOutput(DefaultNHttpServerConnection.java:323)
at org.apache.synapse.transport.http.conn.LoggingNHttpServerConnection.produceOutput(LoggingNHttpServerConnection.java:112)
at org.apache.synapse.transport.passthru.ServerIODispatch.onOutputReady(ServerIODispatch.java:87)
at org.apache.synapse.transport.passthru.ServerIODispatch.onOutputReady(ServerIODispatch.java:39)
at org.apache.http.impl.nio.reactor.AbstractIODispatch.outputReady(AbstractIODispatch.java:143)
at org.apache.http.impl.nio.reactor.BaseIOReactor.writable(BaseIOReactor.java:180)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:342)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:316)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:277)
at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:105)
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:584)
at java.lang.Thread.run(Thread.java:662)

Apparently the server tries to do some IO operation on an already closed channel. I want to write a client program to reproduce the issue at will. The client deliberately closes the channel resulting the server to throw the Exception. This is the code for the client.

public class Client
{
    String hostIp;
    int hostPort;

    public Client(String hostIp, int hostPort) {
        this.hostIp = hostIp;
        this.hostPort = hostPort;
    }

    public void runClient() throws IOException {
        Socket clientSocket = null;
        PrintWriter out = null;
        BufferedReader in = null;

        try {
            clientSocket = new Socket(hostIp, hostPort);
            out = new PrintWriter(clientSocket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        } catch (UnknownHostException e) {
            System.err.println("Unknown host: " + hostIp);
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't connect to: " + hostIp);
            System.exit(1);
        }

        String getMessage = "GET /services/echo?wsdl2 HTTP/1.1\n" +
                "Host:localhost\n";

        System.out.println("Client connected to host : " + hostIp + " port: " + hostPort);

        out.println(getMessage);

        in.close();
        out.close();
        clientSocket.close();
    }

    public static void main(String[] args) throws IOException {

        Client client = new Client("localhost", 8280);
        client.runClient();
    }
}

When the client is run, the server just throws an IOException informing that the pipe is broken.

java.io.IOException: Broken pipe
    at sun.nio.ch.FileDispatcher.write0(Native Method)
    at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:29)
    at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:69)
    at sun.nio.ch.IOUtil.write(IOUtil.java:40)
    at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:336)
    at org.apache.http.impl.nio.reactor.SessionOutputBufferImpl.flush(SessionOutputBufferImpl.java:100)
    at org.apache.http.impl.nio.DefaultNHttpServerConnection.produceOutput(DefaultNHttpServerConnection.java:220)
    at org.apache.synapse.transport.http.conn.LoggingNHttpServerConnection.produceOutput(LoggingNHttpServerConnection.java:112)
    at org.apache.synapse.transport.passthru.ServerIODispatch.onOutputReady(ServerIODispatch.java:87)
    at org.apache.synapse.transport.passthru.ServerIODispatch.onOutputReady(ServerIODispatch.java:39)
    at org.apache.http.impl.nio.reactor.AbstractIODispatch.outputReady(AbstractIODispatch.java:141)
    at org.apache.http.impl.nio.reactor.BaseIOReactor.writable(BaseIOReactor.java:181)
    at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:346)
    at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:320)
    at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:280)
    at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:106)
    at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:604)
    at java.lang.Thread.run(Thread.java:662)

What should I do from the client side to make the server throw a "ClosedChannelException" ?

Answer 1

How to close a socket channel from client side so that the server throws java.nio.channels.ClosedChannelException

You can't.

What should I do from the client side to make the server throw a "ClosedChannelException" ?

Nothing.

You have a basic misunderstanding of ClosedChannelException. It is thrown when you have closed your local Channel and have kept using it. Not when the connection has been closed by the peer.

If you are looking for an end-of-stream indication, use the case where read() returns -1.

If you are looking for an indication of a dropped or failed connection, use the case where write() throws IOException: connection reset .