Apache Mina 2.x 超详实例

　　首先，Mina是个什么东西？看下官方网站（http://mina.apache.org/）对它的解释：

　　Apache的Mina（Multipurpose Infrastructure Networked Applications）是一个网络应用框架，可以帮助用户开发高性能和高扩展性的网络应用程序；它提供了一个抽象的、事件驱动的异步API，使Java NIO在各种传输协议（如TCP/IP，UDP/IP协议等）下快速高效开发。

　　Apache Mina也称为：

• NIO框架
• 客户端/服务端框架（典型的C/S架构）
• 网络套接字（networking socket）类库
• 事件驱动的异步API(注意：在JDK7中也新增了异步API)

总之：我们简单理解它是一个封装底层IO操作，提供高级操作API的通讯框架！

在Mina的官网、以及网上都有比较丰富的文档了，这里我就稍微简单说一下Mina的结构和示例代码。

因为Mina2.X改进了Mina的代码结构和包结构，降低了使用的复杂性和增强了健壮性，所以使得API发生了比较大的改变，有许多地方已经和Mina1.x不兼容了。

这里使用的是Mina2.0.4

1.Mina的结构

Mina的通信流程大致如上图所示，各个组件功能有：
(1.)  IoService：这个接口在一个线程上负责套接字的建立，拥有自己的Selector，监
听是否有连接被建立。

（Mina底层使用JAVA NIO， 因此它是典型的使用Reactor模式架构的,采用事件驱动编程 , Mina运行用户自定义线程模型，可以是单线程、多线程、线程池等 ,

   跟JAVA Socket不一样， Mina是非阻塞的Socket，它内部已经保证了对各个连接(session)的业务和数据的隔离，采用轮询机制为各个session分配CPU资源，

　　所以，你就不需要再去考虑不同Socket连接需要用不同的线程去操纵的问题了。)

(2.)  IoProcessor：这个接口在另一个线程上负责检查是否有数据在通道上读写，也就是
说它也拥有自己的Selector，这是与我们使用JAVA NIO 编码时的一个不同之处，
通常在JAVA NIO 编码中，我们都是使用一个Selector，也就是不区分IoService
与 IoProcessor 两个功能接口。另外，IoProcessor 负责调用注册在IoService 上
的过滤器，并在过滤器链之后调用IoHandler。

(3.)  IoFilter：这个接口定义一组拦截器，这些拦截器可以包括日志输出、黑名单过滤、
数据的编码（write 方向）与解码（read 方向）等功能，其中数据的encode 与 decode
是最为重要的、也是你在使用Mina 时最主要关注的地方。

(4.)  IoHandler：这个接口负责编写业务逻辑，也就是接收、发送数据的地方。
 

2. Mina编程的大致过程.

    2.1 总体流程

        建立服务器端的资源： 包括 Acceptor的建立，之后为Acceptor配置相应的Filter(可以是Mina自带的Filter或者自定义的Filter），

之后再配置相应基于事件驱动的处理业务逻辑的IoHandler.

       建立客户端的资源： Mina采用了统一的编程模型，所以建立客户端的过程和建立服务器端的过程大致上是相似的，不过这里建立的是Connector.

   2.2 示例程序。(使用jar包为 mina-core-2.0.4.jar）

    　　下面通过一个简单的示例程序来进一步理解Mina的运行机制。

 　　　　该程序实现简单的即时通讯功能。 即，多个客户端可以同时脸上服务器，并进行类似于聊天室一样的通信。

       2.2.1 建立自定义的TextLineCodecFacotry

             为了了解Mina的代码功能以及运行机制，我们模拟实现了类似Mina自带TextLineCodecFactory。

　　　　该CodecFactory功能是： 配合ProtocolCodecFilter 进行对底层数据(binary二进制数据流)和高层数据(特定类型的数据对象信息，例如String)之间的转换。

　　　　　　　　　　　　　　　　这里实现了一个断行读取功能，即遇到'\n'的时候，就认为是一个String Line ， 将这段数据流封装成String，之后再交给下一个Filter或者Handler处理。

　　　　　　　　　　　　　　　　CodecFactory是一个工厂方法，底层通过一个Decoder和Encoder来提供对数据进行解、编码的操作,载体是IoBuffer。

　　　　　　　　　　　　　　　　（解码：将二进制数据转换成高层数据(对象)　　　　编码：将高层数据(对象)转换成二进制数据流)  )

　　　　 1）建立Decoder (MyTextLineDecoder)

　　　　　　实现了ProtocolDecoder接口

View Code 

package com.mai.mina.diyCodecFilter;

import java.nio.charset.Charset;

import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;

public class MyTextLineDecoder implements ProtocolDecoder{

    Charset charset = Charset.forName("UTF-8");
    IoBuffer buf = IoBuffer.allocate(100).setAutoExpand(true);
    
    @Override
    public void decode(IoSession session, IoBuffer in, ProtocolDecoderOutput output)
            throws Exception {
        // TODO Auto-generated method stub
        while(in.hasRemaining()){
            byte b = in.get();
            if(b == '\n'){
                buf.flip();
                byte[] bytes = new byte[buf.limit()];
                buf.get(bytes);
                String message = new String(bytes,charset);
                buf = IoBuffer.allocate(100).setAutoExpand(true);
                
                output.write(message);
            }else{
                buf.put(b);
            }
        }
    }

    @Override
    public void dispose(IoSession arg0) throws Exception {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void finishDecode(IoSession arg0, ProtocolDecoderOutput arg1)
            throws Exception {
        // TODO Auto-generated method stub
        
    }

}

　　　　　　实现了ProtocolEncoder接口

View Code 

package com.mai.mina.diyCodecFilter;

import java.nio.charset.Charset;

import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolEncoder;
import org.apache.mina.filter.codec.ProtocolEncoderOutput;
import org.apache.mina.filter.codec.textline.LineDelimiter;

public class MyTextLineEncoder implements ProtocolEncoder{

    Charset charset = Charset.forName("UTF-8");
    
    @Override
    public void dispose(IoSession session) throws Exception {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void encode(IoSession session, Object message, ProtocolEncoderOutput output)
            throws Exception {
        // TODO Auto-generated method stub
        IoBuffer buf = IoBuffer.allocate(100).setAutoExpand(true);
        
        buf.putString(message.toString(), charset.newEncoder());
        
        buf.putString(LineDelimiter.DEFAULT.getValue(), charset.newEncoder());
        buf.flip();
        
        output.write(buf);
        
    }

}

　　　　　　实现了ProtocolCodecFactory接口

package com.mai.mina.diyCodecFilter;

import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolCodecFactory;
import org.apache.mina.filter.codec.ProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolEncoder;

public class MyTextLineCodecFactory implements ProtocolCodecFactory{

    @Override
    public ProtocolDecoder getDecoder(IoSession arg0) throws Exception {
        // TODO Auto-generated method stub
        return new MyTextLineDecoder();
    }

    @Override
    public ProtocolEncoder getEncoder(IoSession arg0) throws Exception {
        // TODO Auto-generated method stub
        return new MyTextLineEncoder();
    }

}

　　　　1). 建立自定义IoHandler（MyServerHandleDemo1)

　　　　　　实现了IoHandler接口。

View Code 

package com.mai.mina.diyChat;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Date;
import java.util.logging.Logger;

import org.apache.mina.core.future.CloseFuture;
import org.apache.mina.core.future.IoFuture;
import org.apache.mina.core.future.IoFutureListener;
import org.apache.mina.core.service.IoHandler;
import org.apache.mina.core.session.IdleStatus;
import org.apache.mina.core.session.IoSession;


public class MyServerHandleDemo1 implements IoHandler{

    private Logger logger = Logger.getLogger(this.getClass().getName());
    
    @Override
    public void exceptionCaught(IoSession session, Throwable arg1)
            throws Exception {
        // TODO Auto-generated method stub
        logger.warning("服务器启动发生异常，have a exception : " + arg1.getMessage());
    }

    @Override
    public void messageReceived(IoSession session, Object message) throws Exception {
        // TODO Auto-generated method stub
        String messageStr = message.toString();
        DateFormat format = new SimpleDateFormat("yyyy-MM-dd H:m:s");
        String dateStr = format.format(new Date());
        
        logger.info(messageStr + "\t" + dateStr);
        
        Collection<IoSession> sessions = session.getService().getManagedSessions().values();
        for(IoSession tempSession : sessions){
            tempSession.write(messageStr + "\t" + dateStr);
        }
    }

    @Override
    public void messageSent(IoSession session, Object message) throws Exception {
        // TODO Auto-generated method stub
        logger.info("服务器成功发送信息: " + message.toString());
    }

    @Override
    public void sessionClosed(IoSession session) throws Exception {
        // TODO Auto-generated method stub
        logger.info("there is a session closed");
        CloseFuture future = session.close(true);
        future.addListener(new IoFutureListener(){
            public void operationComplete(IoFuture future){
                if(future instanceof CloseFuture){
                    ((CloseFuture)future).setClosed();
                    logger.info("have do the future set to closed");
                }
            }
        });
    }

    @Override
    public void sessionCreated(IoSession session) throws Exception {
        // TODO Auto-generated method stub
        logger.info("there is a session created");
        session.write("welcome to the chat room");
    }

    @Override
    public void sessionIdle(IoSession session, IdleStatus arg1) throws Exception {
        // TODO Auto-generated method stub
        logger.info(session.getId() + "(SesssionID) is idle in the satate-->" + arg1);
    }

    @Override
    public void sessionOpened(IoSession arg0) throws Exception {
        // TODO Auto-generated method stub
        
    }

    
}

2).建立Acceptor ，同时也充当Server端的启动类 (SimpleMinaServer)

package com.mai.mina.diyChat;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.charset.Charset;

import org.apache.mina.core.session.IdleStatus;
import org.apache.mina.filter.codec.ProtocolCodecFilter;
import org.apache.mina.filter.codec.textline.LineDelimiter;
import org.apache.mina.filter.codec.textline.TextLineCodecFactory;
import org.apache.mina.filter.logging.LogLevel;
import org.apache.mina.filter.logging.LoggingFilter;
import org.apache.mina.transport.socket.SocketAcceptor;
import org.apache.mina.transport.socket.nio.NioSocketAcceptor;

public class SimpleMinaServer {
    
    SocketAcceptor acceptor = null;
    
    SimpleMinaServer(){
        acceptor = new NioSocketAcceptor();
    }
    
    public boolean bind(){
        acceptor.getFilterChain().addLast("codec", new ProtocolCodecFilter(
                new MyTextLineCodecFactory()); //配置CodecFactory
        LoggingFilter log = new LoggingFilter();
        log.setMessageReceivedLogLevel(LogLevel.INFO);
        acceptor.getFilterChain().addLast("logger", log);
        acceptor.setHandler(new MyServerHandleDemo1());　　//配置handler
        acceptor.getSessionConfig().setIdleTime(IdleStatus.BOTH_IDLE, 30);
        
        try {
            acceptor.bind(new InetSocketAddress(8888));
            return true;
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return false;
        }
        
    }
    
    public static void main(String args[]){
        SimpleMinaServer server = new SimpleMinaServer();
        if(!server.bind()){
            System.out.println("服务器启动失败");
        }else{
            System.out.println("服务器启动成功");
        }
    }

}

　　　　1）自定义IoHandler(MyClientHandleDemo1)

　　　　　　实现IoHandler接口

View Code 

package com.mai.mina.diyChat;

import java.util.logging.Logger;

import org.apache.mina.core.service.IoHandlerAdapter;
import org.apache.mina.core.session.IoSession;

public class MyClientHandleDemo1 extends IoHandlerAdapter{
    private ChatPanel messagePanel = null;
    private Logger logger = Logger.getLogger(this.getClass().getName());

    MyClientHandleDemo1(){
        
    }
    
    MyClientHandleDemo1(ChatPanel messagePanel){
        this.messagePanel = messagePanel;
    }
    
    
    public void messageReceived(IoSession session, Object message) throws Exception {
        // TODO Auto-generated method stub
        String messageStr = message.toString();
        logger.info("receive a message is : " + messageStr);
        
        if(messagePanel != null)
        messagePanel.showMsg(messageStr);
    }
    
    public void messageSent(IoSession session , Object message) throws Exception{
        logger.info("客户端发了一个信息：" + message.toString());
    }
    
}

View Code 

package com.mai.mina.diyChat;

import java.net.InetSocketAddress;
import java.nio.charset.Charset;

import org.apache.mina.core.future.CloseFuture;
import org.apache.mina.core.future.ConnectFuture;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolCodecFilter;
import org.apache.mina.filter.codec.textline.LineDelimiter;
import org.apache.mina.filter.codec.textline.TextLineCodecFactory;
import org.apache.mina.filter.logging.LogLevel;
import org.apache.mina.filter.logging.LoggingFilter;
import org.apache.mina.transport.socket.SocketConnector;
import org.apache.mina.transport.socket.nio.NioSocketConnector;

public class SimpleMinaClient {

    public SocketConnector connector = null;
    public ConnectFuture future;
    public IoSession session = null;
    private ChatPanel messagePanel = null;
    
    SimpleMinaClient(){
        
    }
    
    SimpleMinaClient(ChatPanel messagePanel){
        this.messagePanel = messagePanel;
    }
    
    
    boolean connect(){
        try{
            connector = new NioSocketConnector();
            connector.setConnectTimeoutMillis(3000);
            connector.getFilterChain().addLast("codec", new ProtocolCodecFilter(
                new MyTextLineCodecFactory());
            LoggingFilter log = new LoggingFilter();
            log.setMessageReceivedLogLevel(LogLevel.INFO);
            connector.getFilterChain().addLast("logger", log);
            connector.setHandler(new MyClientHandleDemo1(messagePanel));
            
            future = connector.connect(new InetSocketAddress("127.0.0.1" , 8888));
            future.awaitUninterruptibly();
            session = future.getSession();
            return true;
        }catch(Exception e){
            e.printStackTrace();
            return false;
        }
        
    }
    
    
    public void setAttribute(Object key , Object value){
        session.setAttribute(key, value);
    }
    
    
    void sentMsg(String message){
        session.write(message);
    }
    
    
    boolean close(){
        CloseFuture future = session.getCloseFuture();
        future.awaitUninterruptibly(1000);
        connector.dispose();
        return true;
    }
    
    public SocketConnector getConnector() {
        return connector;
    }


    public IoSession getSession() {
        return session;
    }


    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        SimpleMinaClient client = new SimpleMinaClient();
        if(client.connect()){
            client.sentMsg("hello , sever !");
            client.close();
        }
        
    }

}

　　接下来实现一个客户端的GUI界面，方便实际功能的建立和信息交互的演示。

　　2.2.4 Client Gui界面的建立。(ChatPanel -通过使用SimpleMinaClient来提供实际通信功能)

View Code 

package com.mai.mina.diyChat;
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

import org.apache.commons.lang.math.RandomUtils;

public class ChatPanel extends javax.swing.JPanel {
    private JPanel northPanel;
    private JLabel headLabel;
    private JScrollPane jScrollPane1;
    private JScrollPane jScrollPane2;
    private JButton exitB;
    private JButton clearMsgB;
    private JButton sentB;
    private JButton connectB;
    private JTextArea messageText;
    private JTextField nameText;
    private JLabel nameLabel;
    private JTextArea messageArea;
    private JPanel southPanel;
    private SimpleMinaClient client = null;
    private boolean connected = false;
    private String username = null;

    {
        //Set Look & Feel
        try {
            javax.swing.UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
        } catch(Exception e) {
            e.printStackTrace();
        }
    }

    public void connect(){
        if(client.connect()){
            username = nameText.getText().trim();
            if(username == null || "".equals(username)){
                username = "游客" + RandomUtils.nextInt(1000);
                nameText.setText(username);
            }
            connected = true;
            dealUIWithFlag();
        }else{
            connected = false;   
            dealUIWithFlag();
            showMsg("连接服务器失败。。。");
        }
    }
    
    
    public void showMsg(String msg){
        messageArea.append(msg);
        messageArea.append("\n");
        messageArea.selectAll();
        messageArea.lostFocus(null, this);
    }
    
    
    public void sentMsg(){
        String message = username + ":" + messageText.getText();
        client.sentMsg(message);
        messageText.setText("");
        messageText.requestFocus();
    }
    
    public void dealUIWithFlag(){
        if(connected){
            nameText.setEnabled(false);
            connectB.setEnabled(false);
            sentB.setEnabled(true);
            clearMsgB.setEnabled(true);
            exitB.setEnabled(true);
        }else{
            nameText.setEnabled(true);
            connectB.setEnabled(true);
            sentB.setEnabled(false);
            clearMsgB.setEnabled(false);
            exitB.setEnabled(false);
        }
    }
    
    
    public void closeTheClient(){
        if(client.close()){
            showMsg("连接已断开...");
            connected = false;
            dealUIWithFlag();
        }else{
            showMsg("无法断开连接...");
        }
    }
    

    
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.getContentPane().add(new ChatPanel());
        frame.addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent e){
                System.exit(0);
            }
        });
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }
    
    public ChatPanel() {
        super();
        client = new SimpleMinaClient(this);
        initGUI();
        dealUIWithFlag();
    }
    
    private void initGUI() {
        try {
            this.setPreferredSize(new java.awt.Dimension(400, 339));
            this.setLayout(null);
            {
                northPanel = new JPanel();
                BorderLayout northPanelLayout = new BorderLayout();
                northPanel.setLayout(northPanelLayout);
                this.add(northPanel);
                northPanel.setBounds(0, 0, 400, 188);
                {
                    headLabel = new JLabel();
                    northPanel.add(headLabel, BorderLayout.NORTH);
                    headLabel.setText("\u6b22\u8fce\u4f7f\u7528 (\u6d4b\u8bd5Ip:port --> 127.0.0.1:8888)");
                    headLabel.setPreferredSize(new java.awt.Dimension(397, 19));
                }
                {
                    jScrollPane1 = new JScrollPane();
                    northPanel.add(jScrollPane1, BorderLayout.CENTER);
                    jScrollPane1.setPreferredSize(new java.awt.Dimension(400, 169));
                    {
                        messageArea = new JTextArea();
                        jScrollPane1.setViewportView(messageArea);
                        messageArea.setPreferredSize(new java.awt.Dimension(398, 145));
                        messageArea.setEditable(false);
                        messageArea.setLineWrap(true);
                        messageArea.setWrapStyleWord(true);
                    }
                }
            }
            {
                southPanel = new JPanel();
                this.add(southPanel);
                southPanel.setBounds(0, 194, 400, 145);
                southPanel.setLayout(null);
                {
                    nameLabel = new JLabel();
                    southPanel.add(nameLabel);
                    nameLabel.setText("\u6635\u79f0:");
                    nameLabel.setBounds(10, 12, 35, 15);
                }
                {
                    nameText = new JTextField();
                    southPanel.add(nameText);
                    nameText.setText("\u6e38\u5ba2");
                    nameText.setBounds(45, 9, 96, 21);
                }
                {  
                    jScrollPane2 = new JScrollPane();
                    southPanel.add(jScrollPane2);
                    jScrollPane2.setBounds(15, 37, 364, 69);
                    {
                        messageText = new JTextArea();
                        jScrollPane2.setViewportView(messageText);
                        messageText.setBounds(101, 72, 362, 75);
                        messageText.setPreferredSize(new java.awt.Dimension(362, 54));
                        messageText.setLineWrap(true);
                        messageText.setWrapStyleWord(true);
                    }
                }
                {
                    connectB = new JButton();
                    southPanel.add(connectB);
                    connectB.setText("\u8fde\u63a5\u670d\u52a1\u5668");
                    connectB.setBounds(179, 8, 93, 23);
                    connectB.addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent evt) {
                            System.out.println("connectB.actionPerformed, event="+evt);
                            //TODO add your code for connectB.actionPerformed
                            connect();
                        }
                    });
                }
                {
                    sentB = new JButton();
                    southPanel.add(sentB);
                    sentB.setText("\u53d1\u9001");
                    sentB.setBounds(261, 116, 57, 23);
                    sentB.addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent evt) {
                            System.out.println("sentB.actionPerformed, event="+evt);
                            //TODO add your code for sentB.actionPerformed
                            sentMsg();
                        }
                    });
                }
                {
                    clearMsgB = new JButton();
                    southPanel.add(clearMsgB);
                    clearMsgB.setText("\u6e05\u7a7a");
                    clearMsgB.setBounds(324, 116, 57, 23);
                    clearMsgB.addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent evt) {
                            System.out.println("clearMsgB.actionPerformed, event="+evt);
                            //TODO add your code for clearMsgB.actionPerformed
                            messageText.setText("");
                        }
                    });
                }
                {
                    exitB = new JButton();
                    southPanel.add(exitB);
                    exitB.setText("\u6ce8\u9500");
                    exitB.setBounds(282, 8, 57, 23);
                    exitB.addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent evt) {
                            System.out.println("exitB.actionPerformed, event="+evt);
                            //TODO add your code for exitB.actionPerformed
                            closeTheClient();
                        }
                    });
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        } 
    }

}

　　首先启动服务器端，即运行SimpleMinaServer类 ， 启动成功时会在控制台中打印出“服务器启动成功"

　　接下来运行客户端ChatPanel。

note: 上面只是一个简单的信息交互，其实使用Mina比较常用的还是在自定义协议处理这块。