Apache Mina使用

Apache Mina 入门 MINA 基本类的描述

IoAccepter 相当于网络应用程序中的服务器端

IoConnector 相当于客户端

IoSession 当前客户端到服务器端的一个连接实例

IoHandler 业务处理逻辑

IoFilter 过滤器用于悬接通讯层接口与业务层接口

 

服务器端：MinaServer.java
public class MinaServer {
             private static final int SERVER_PORT = 9990;
    
             public static void main(String[] args) throws Throwable{
                             //服务端入口
                            IoAcceptor acceptor = new SocketAcceptor();
                            SocketAcceptorConfig cfg = new SocketAcceptorConfig();
                            cfg.setReuseAddress( true);
                             //设定这个过滤器将以对象为单位读取数据
                            cfg.getFilterChain().addLast( "codec",
new ProtocolCodecFilter( new ObjectSerializationCodecFactory()));
                             //添加日志过滤器
                            cfg.getFilterChain().addLast( "logger", new LoggingFilter());
                             //接收访问的连接和到IoHandler触发事件
             acceptor.bind( new InetSocketAddress(SERVER_PORT), new ServerHandler(), cfg);
                            System.out.println( "The server Listening on port " + SERVER_PORT);
             }
}    
    
服务器端业务处理类：
public class ServerHandler extends IoHandlerAdapter
{
             /**
                * 有新连接时触发
                */
             public void sessionOpened(IoSession session) {
                            System.out.println( "sessionOpened");
             }
             /**
                * 收到来自客户端的消息
                */
             public void messageReceived(IoSession session, Object message) {
                            System.out.println( "server messageReceived!");
                            CityMessage cm = (CityMessage)message;
                            System.out.println(cm.getCode()+ ":"+cm.getName());
                             //将消息发向客户端
                            session.write(cm);
             }
             /**
                * 当有异常发生时触发
                */
             public void exceptionCaught(IoSession session, Throwable cause) {
                            session.close();
             }
             /**
                * 连接被关闭时触发
                */
             public void sessionClosed(IoSession ssn) throws Exception {
                            System.out.println( "session closed from " + ssn.getRemoteAddress());
             }
}    
    
要发送的消息对象：
public class CityMessage implements Serializable{
             private int code;
             private String name;
             public int getCode() {
                             return code;
             }
             public void setCode( int code) {
                             this.code = code;
             }
             public String getName() {
                             return name;
             }
             public void setName(String name) {
                             this.name = name;
             }
}    
    
客户端：
public class MinaClient {
             private static final String HOSTNAME = "localhost";        
         private static final int PORT = 9990;        
    
         public static void main( String[] args ) throws Throwable{        
                 //Connector为客户端入口
                     SocketConnector connector = new SocketConnector();                        
                SocketConnectorConfig cfg = new SocketConnectorConfig();        
                 //设定这个过滤器将以对象为单位读取数据
                cfg.getFilterChain().addLast( "codec",    
                                                                                                                         new ProtocolCodecFilter( new ObjectSerializationCodecFactory() ) );        
                 //添加日志过滤器
                cfg.getFilterChain().addLast( "logger", new LoggingFilter() );        
                 //向远程服务器发起连接，触发事件到IoHandler    
                connector.connect( new InetSocketAddress( HOSTNAME, PORT ),        
                                                 new ClientHandler(), cfg );        
        }        
}    
    
客户端业务处理类：
public class ClientHandler extends IoHandlerAdapter {
             public ClientHandler() {
                             super();
             }
             /**
                * 有新连接时触发
                */
             public void sessionOpened(IoSession session) {
                             // 创建一个cityMessage发送
                            CityMessage cm = new CityMessage();
                            cm.setCode(547600);
                            cm.setName( "凤山");
                            session.write(cm);
             }
             /**
                * 收到来自客户端的消息
                */
             public void messageReceived(IoSession session, Object message) {
                            System.out.println( "client messageReceived!");
                            CityMessage cm = (CityMessage)message;
                            System.out.println(cm.getCode()+ ":"+cm.getName());
             }
             /**
                * 当有异常发生时触发
                */
             public void exceptionCaught(IoSession session, Throwable cause) {
                            session.close();
             }
             /**
                * 连接被关闭时触发
                */
             public void sessionClosed(IoSession ssn) throws Exception {
                            System.out.println( "session closed from " + ssn.getRemoteAddress());
             }
}    

开发一个 Mina 应用，简单的说，就是创建连结，设定过滤规则，编写自己的消息处理器这三步！

 

过滤器：

ObjectSerializationCodecFactory ：设定这个过滤器将以对象为单位读取数据。

TextLineCodecFactory ：设定这个过滤器将一行一行 (/r/n) 的读取数据

 

注意：（摘抄自网上） 由 apache mina 建立的 socket 不管是采用 TCP 或是 UDP ，在 Filter 不添加 codec 选项的情况下，由 IoHandlerAdapter 派生的处理 handler 类中 public void messageReceived(IoSession session, Object message){} 函数里的 message 对象是 IoBuffer 的实例，如下：

@Override
         public void messageReceived(IoSession session, Object message)
                         throws Exception {

                 if (! (message instanceof IoBuffer)) {
                             return;
                     }

                IoBuffer rb = (IoBuffer) message;
                callback.messageReceived(java.nio.ByteBuffer.wrap(rb.array(), 0, rb.buf().limit()));
        }

如果你使用 mina 建立一个 socket 添加了如下：
IoFilter CODEC_FILTER = new ProtocolCodecFilter(
                new TextLineCodecFactory());
connector(acceptor).getFilterChain().addLast("codec", CODEC_FILTER);
如果发送数据的 socket 不是同样的设置或者不是利用 mina 建立的 socket 则发送数据的时候需要在数据末尾添加 ‘\n’ ，以表示字符串结束。