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我有以下 java NIO 服务器和一个 python asyncore 客户端。服务器打印“Accepted...\n”，但是，客户端的 handle_connect 永远不会被调用。有人可以帮我解决服务器出了什么问题并帮助我使用客户端连接到服务器吗？

Java NIO 服务器：

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.channels.SelectableChannel;
import java.nio.channels.Selector;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Set;

class Server
{
    public Selector sel;
    public ServerSocketChannel ssc;
    public SocketChannel channel;
    public static void main(String[] args) throws Exception
    {
        Server s = new Server();
        s.openSocket(12000);
        s.run();
    }

    private void openSocket(int port) throws Exception
    {
        InetSocketAddress address = new InetSocketAddress("0.0.0.0", port);
        ssc = ServerSocketChannel.open();
        ssc.configureBlocking(false);
        ssc.socket().bind(address);
        sel = Selector.open();
        ssc.register(sel, SelectionKey.OP_ACCEPT);
    }

    public void run() throws Exception
    {
        while (true)
        {
            sel.select();
            Set<SelectionKey> keys = sel.selectedKeys();
            Iterator<SelectionKey> i = keys.iterator();
            while (i.hasNext())
            {
                SelectionKey key = (SelectionKey) i.next();
                i.remove();
                if (!key.isValid())
                {
                    continue;
                }
                if (key.isAcceptable())
                {
                    channel = ssc.accept();
                    channel.configureBlocking(false);
                    System.out.println("Accepted...\n");
                    channel.register(sel, SelectionKey.OP_READ);
                }
                if (key.isReadable())
                {
                    if (channel == key.channel())
                    {
                        System.out.println("Readable\n");
                        ByteBuffer buffer = ByteBuffer.wrap(new byte[1024]);
                        int pos = channel.read(buffer);
                        buffer.flip();
                        System.out.println(new String(buffer.array(), 0, pos));
                    }
                }
            }
        }
    }   
}

Python异步客户端：

import socket
import select
import asyncore

class Connector(asyncore.dispatcher):
    def __init__(self, host, port):
        asyncore.dispatcher.__init__(self)
        self.buffer = "hi"
        self.create_socket()
        self.connect((host, port))

    def handle_connect(self):
        print("[]---><---[]") # not called <------------------

    def handle_read(self):
        pass

    def writable(self):
        len(self.buffer) > 0

    def handle_write(self):
        sent = self.send(self.buffer)
        print("[]--->" + self.buffer[0:sent])
        self.buffer = self.buffer[sent:]

    def handle_close(self):
        print("[]...x...[]")
        self.close()


connector = Connector("localhost", 12000, Handler())
asyncore.loop()

Python正常工作客户端：

# Echo client program
import socket
import sys

HOST = 'localhost'    # The remote host
PORT = 12000              # The same port as used by the server
s = None
for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
    af, socktype, proto, canonname, sa = res
    try:
        s = socket.socket(af, socktype, proto)
        print("socket")
    except OSError as msg:
        s = None
        continue
    try:
        s.connect(sa)
        print("connected")
    except OSError as msg:
        s.close()
        s = None
        continue
    break
if s is None:
    print('could not open socket')
    sys.exit(1)
print("Sending")
s.sendall(bytes("Hey server", "UTF-8"))
data = s.recv(1024)
#    s.close()
print('Received', repr(data))

编辑向 Java 添加了 isReadable 并添加了正常工作的 python 客户端。

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1 回答 1

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您在实现其中一种乏味的异步方法时犯了两个错误：

def writable(self):
    len(self.buffer) > 0

此方法返回None（因为您忘记了return该语句的一部分）。第一个错误是None具有错误的布尔值，因此Connector永远不会被认为是可写的。第二个错误是您需要在尝试建立连接期间检查可写性。由于writable总是返回 false，包括在连接尝试期间，所以在建立连接方面没有取得任何进展。

我建议改为查看Twisted 。它不会让您自己实现低级缓冲区管理和连接设置代码，因此实际上会产生更高效的代码，这些代码更短且更容易编写。

asyncore 应该真正被视为历史文物，从未实际使用过。

于 2013-02-05T16:11:07.230 回答