(一)androidpn-server tomcat版源码解析之--项目启动

最新项目在搞安卓推送,选用的xmpp协议,用了一套androidpn推送框架服务端是tomcat的版本的androidpn-server,网上对于这套服务端源码的理解比较少,于是我抽空把源码给解析了一遍并且了解到了整个服务的启动过程。

下面是项目的git地址:https://github.com/msdx/androidpn/tree/master/androidpn-server-bin-tomcat

工程本身是一套tomcat的web工程,有控制台,本文将从工程建立的视角来观察源码

  •  入口web.xml

和大多数web工程一样,本项目的入口也是web.xml,通过web.xml启动spring,下面是源码

web.xml

<context-param>									
		<param-name>contextConfigLocation</param-name>							
		<param-value>							
			/WEB-INF/applicationContext*.xml						
        </param-value>									
</context-param>

 实际上WEB-INF下并没有applicationContext*.xml(估计是没有配置正确),而是使用了dispatcher-servlet.xml

dispatcher-servlet.xml

<bean id="notificationController"			
	class="org.androidpn.server.console.controller.NotificationController">		
	<property name="methodNameResolver" ref="paramResolver" />		
</bean>

 在dispatcher-servlet.xml中配置了一个Controller,spring初始化时候会去调用NotificationController的构造方法来生成一个实例

NotificationApiController的构造方法

public NotificationApiController() {				
        notificationManager = new NotificationManager();				
    }

NotificationManager的构造方法

/**			
     * Constructor.			
     */			
public NotificationManager() {			
   sessionManager = SessionManager.getInstance();			
   notificationService = ServiceLocator.getNotificationService();			
   userService = ServiceLocator.getUserService();			
}

 ServiceLocator.getNotificationService()和ServiceLocator.getUserService()其实就是从spirng的bean工程中获取service方法不用太在意,下一步到SessionManager.getInstance()

SessionManager

private SessionManager() {				
   serverName = XmppServer.getInstance().getServerName();//####启动了XmppServer,成为了重要线索			
}				
	
			
    /**				
     * Returns the singleton instance of SessionManager.				
     * 				
     * @return the instance				
     */				
public static SessionManager getInstance() {				
     if (instance == null) {				
        synchronized (SessionManager.class) {				
           instance = new SessionManager();				
          }				
      }				
      return instance;				
    }
  • Mina  server

他的名字虽然是XmppServer,但其实只是load了另外一个spirng的xml,从整体的角度来说,XmppServer的作用是开启一个mina的监听server端,下面先来补充一下mina的知识

一句话概括:mina为开发高性能和高可用性的网络应用程序提供了非常便利的框架。也就是说它是一套网络通信框架,基于socket的。

他的demo如下

public class HelloServer {

	private static final int PORT = 8080;

	/**
	 * @param args
	 * @throws IOException
	 */
	public static void main(String[] args) throws IOException {
		IoAcceptor acceptor = new SocketAcceptor();
		IoAcceptorConfig config = new SocketAcceptorConfig();
		DefaultIoFilterChainBuilder chain = config.getFilterChain();
		// 使用字符串编码
		chain.addLast("codec", new ProtocolCodecFilter(new TextLineCodecFactory()));
		// 启动HelloServer
		acceptor.bind(new InetSocketAddress(PORT), new HelloHandler(), config);
		System.out.println("HelloServer started on port " + PORT);
	}
}

/**
 * HelloServer的处理逻辑
 * 
 * @author liudong
 */
class HelloHandler extends IoHandlerAdapter {
	/**
	 * 当有异常发生时触发
	 */
	@Override
	public void exceptionCaught(IoSession ssn, Throwable cause) {
		cause.printStackTrace();
		ssn.close();
	}

	/**
	 * 有新连接时触发
	 */
	@Override
	public void sessionOpened(IoSession ssn) throws Exception {
		System.out.println("session open for " + ssn.getRemoteAddress());
	}

	/**
	 * 连接被关闭时触发
	 */
	@Override
	public void sessionClosed(IoSession ssn) throws Exception {
		System.out.println("session closed from " + ssn.getRemoteAddress());
	}

	/**
	 * 收到来自客户端的消息
	 */
	public void messageReceived(IoSession ssn, Object msg) throws Exception {
		String ip = ssn.getRemoteAddress().toString();
		System.out.println("===> Message From " + ip + " : " + msg);
		ssn.write("Hello " + msg);
	}
}

 再引用一张架构图:

 
(一)androidpn-server  tomcat版源码解析之--项目启动
 整体表达的意思也就是,client的请求最后都会交给handler类去执行,用户自己的handler只要去继承IoHandlerAdapter这个父类,就可以拥有 sessionOpened,sessionClosed,messageReceived的功能,客户端的请求也最终分发到了handler类的对应方法

好了补充完了mina的知识再回到主题,刚才说到XmppServer去load了另外一个spirng.xml,下面是XmppServer.java的源码

/**	
     * Returns the singleton instance of XmppServer.	
     *	
     * @return the server instance.	
     */	
    public static XmppServer getInstance() {	
        // return instance;	
        if (instance == null) {	
            synchronized (XmppServer.class) {	
                instance = new XmppServer();	
            }	
        }	
        return instance;	
    }	
	
    /**	
     * Constructor. Creates a server and starts it.	
     */	
    public XmppServer() {	
        if (instance != null) {	
            throw new IllegalStateException("A server is already running");	
        }	
        instance = this;	
        start();	
    }	
	
    /**	
     * Starts the server using Spring configuration.	
     */	
    public void start() {	
        try {	
            if (isStandAlone()) {	
                Runtime.getRuntime().addShutdownHook(new ShutdownHookThread());	
            }	
	
          //  locateServer();	
            serverName = Config.getString("xmpp.domain", "127.0.0.1")	
                    .toLowerCase();	
            context = new ClassPathXmlApplicationContext("spring-config.xml");	 //#######################没错这个xml的名字在这里
            log.info("Spring Configuration loaded.");	
	
//            AdminConsole adminConsole = new AdminConsole(serverHomeDir);	
//            adminConsole.startup();	
//            if (adminConsole.isHttpStarted()) {	
//                log.info("Admin console listening at http://"	
//                        + adminConsole.getAdminHost() + ":"	
//                        + adminConsole.getAdminPort());	
//            }	
            log.info("XmppServer started: " + serverName);	
            log.info("Androidpn Server v" + version);	
	
        } catch (Exception e) {	
            e.printStackTrace();	
            shutdownServer();	
        }	
    }

 原来是spring-config.xml,下面则是spring-config.xml的关键内容

<bean id="xmppHandler" class="org.androidpn.server.xmpp.net.XmppIoHandler" />			
<bean id="ioAcceptor" class="org.apache.mina.transport.socket.nio.NioSocketAcceptor"			
	init-method="bind" destroy-method="unbind">		
		<property name="defaultLocalAddress" value=":5222" />	
		<property name="handler" ref="xmppHandler" />	
		<property name="filterChainBuilder" ref="filterChainBuilder" />	
		<property name="reuseAddress" value="true" />	
	</bean>

 原来,工程在spirng类中又配了一个bean,这个bean是org.apache.mina.transport.socket.nio.NioSocketAcceptor,并且ioc注入了监听的端口号,以及对应的handler类,打开工程中的org.androidpn.server.xmpp.net.XmppIoHandler类,我们就明白了,所有client的链接最初都被发到这个类中,然后再进行了相应的处理。

以上基本阐述了整个项目的基本流程,下篇文章,我将继续分析XmppIoHandler往下的流程,来看androidpn是如何实现实时推送和链接状态维护的

原创文章,转载请声名出处http://spjich.iteye.com/admin/blogs/2225830

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