java.net.ConnectException:调用SocketChannel.open时连接被拒绝

问题描述

我正在尝试编写一个简单的程序来打开到本地地址的套接字通道.每当我运行此程序时，我都会收到连接被拒绝的异常

I am trying to write a simple program to open a socket channel to a local address. I get a connection refused exception whenever I run this program

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.channels.SocketChannel;

public class testSocket {

        public static void main(String [] args) {
                try {
                        InetAddress addr = InetAddress.getByName("localhost");
                        InetSocketAddress remoteAddress = new InetSocketAddress(addr, 19015);

                        // Open a new Socket channel and set it to non-blocking
                        SocketChannel socketChannel = SocketChannel.open();
                        socketChannel.configureBlocking(false);

                        // Issue the Connect call on the remote address.
                        socketChannel.connect(remoteAddress);
                } catch (Exception e) {
                        e.printStackTrace();
                }
        }
}

我得到的例外是

java.net.ConnectException: Connection refused
        at sun.nio.ch.Net.connect(Native Method)
        at sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:464)
        at testSocket.main(testSocket.java:17)

我在Sun Solaris和HP-UX上遇到此问题.在Linux机器上似乎工作正常.谁能让我知道为什么拒绝连接?我做了一个netstat -a并确认该端口未被使用.

I encounter this issue with Sun Solaris and HP - UX. It seems to work fine on a Linux machine. Can anyone let me know why the connection is being refused? I did a netstat -a and confirmed that the port is not in use.

提前谢谢！

推荐答案

从Javadoc中获取SocketChannel.connect()

From the Javadoc for SocketChannel.connect()

当我在Linux上运行您的代码时，connect()返回false，因此没有异常.如果添加对socketChannel.finishConnect()的调用，您将看到与在Solaris/HP-UX上相同的拒绝连接异常.

When I run your code on Linux, connect() returns false hence there is no exception. If you add a call to socketChannel.finishConnect() you will see the same connection refused exception as you get on Solaris/HP-UX.

我怀疑在Solaris/HP-UX上connect()返回true，因此会立即引发异常.

I suspect that on Solaris/HP-UX connect() returns true hence the exception is thrown immediately.

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