如果您正在使用 NIO，我还建议使用框架。我一直在与阿帕奇·米娜我会推荐它。
至于阻塞 IO，本质上您将需要一个侦听器线程来接受传入连接并生成额外的线程来处理每个连接。以下是此类侦听器代码的示例，最初贡献给 Apache Felix 项目。
如果您寻找完整但经过修改的版本，您可以在这里浏览源代码.
e.g.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.felix.shell.remote;
import java.io.IOException;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
/**
* Implements a simple listener that will accept a single connection.
* <p/>
*
* @author Dieter Wimberger (wimpi)
*/
class Listener
{
private int m_Port;
private Thread m_ListenerThread;
private boolean m_Stop = false;
private ServerSocket m_ServerSocket;
private AtomicInteger m_UseCounter;
private int m_MaxConnections;
/**
* Activates this listener on a listener thread (telnetconsole.Listener).
*/
public void activate()
{
//configure from system property
try
{
m_Port = Integer.parseInt( System.getProperty( "osgi.shell.telnet.port", "6666" ) );
}
catch ( NumberFormatException ex )
{
Activator.getServices().error( "Listener::activate()", ex );
}
try
{
m_MaxConnections = Integer.parseInt( System.getProperty( "osgi.shell.telnet.maxconn", "2" ) );
}
catch ( NumberFormatException ex )
{
Activator.getServices().error( "Listener::activate()", ex );
}
m_UseCounter = new AtomicInteger( 0 );
m_ListenerThread = new Thread( new Acceptor(), "telnetconsole.Listener" );
m_ListenerThread.start();
}//activate
/**
* Deactivates this listener.
* <p/>
* The listener's socket will be closed, which should cause an interrupt in the
* listener thread and allow for it to return. The calling thread joins the listener
* thread until it returns (to ensure a clean stop).
*/
public void deactivate()
{
try
{
m_Stop = true;
//wait for the listener thread
m_ServerSocket.close();
m_ListenerThread.join();
}
catch ( Exception ex )
{
Activator.getServices().error( "Listener::deactivate()", ex );
}
}//deactivate
/**
* Class that implements the listener's accept logic as a <tt>Runnable</tt>.
*/
private class Acceptor implements Runnable
{
/**
* Listens constantly to a server socket and handles incoming connections.
* One connection will be accepted and routed into the shell, all others will
* be notified and closed.
* <p/>
* The mechanism that should allow the thread to unblock from the ServerSocket.accept() call
* is currently closing the ServerSocket from another thread. When the stop flag is set,
* this should cause the thread to return and stop.
*/
public void run()
{
try
{
/*
A server socket is opened with a connectivity queue of a size specified
in int floodProtection. Concurrent login handling under normal circumstances
should be handled properly, but denial of service attacks via massive parallel
program logins should be prevented with this.
*/
m_ServerSocket = new ServerSocket( m_Port, 1 );
do
{
try
{
Socket s = m_ServerSocket.accept();
if ( m_UseCounter.get() >= m_MaxConnections )
{
//reject with message
PrintStream out = new PrintStream( s.getOutputStream() );
out.print( INUSE_MESSAGE );
out.flush();
//close
out.close();
s.close();
}
else
{
m_UseCounter.increment();
//run on the connection thread
Thread connectionThread = new Thread( new Shell( s, m_UseCounter ) );
connectionThread.start();
}
}
catch ( SocketException ex )
{
}
}
while ( !m_Stop );
}
catch ( IOException e )
{
Activator.getServices().error( "Listener.Acceptor::activate()", e );
}
}//run
}//inner class Acceptor
private static final String INUSE_MESSAGE = "Connection refused.\r\n"
+ "All possible connections are currently being used.\r\n";
}//class Listener
你可以找到其他例子here and here.
请注意，当负载较多时，NIO 相对于阻塞模型的优势就会发挥出来。从某一点开始，线程创建、管理和上下文切换的额外工作量将限制您的系统性能。
