Jva NIO框架 Apache Mina 2.x 簡易入門解析

openkk 12年前發布 | 111K 次閱讀網絡工具包 Apache MINA

最近使用Mina開發一個Java的NIO服務端程序，因此也特意學習了Apache的這個Mina框架。

首先，Mina是個什么東西？看下項目主頁（http://mina.apache.org/）對它的解釋：

Apache的Mina（Multipurpose Infrastructure Networked Applications）是一個網絡應用框架，可以幫助用戶開發高性能和高擴展性的網絡應用程序；它提供了一個抽象的、事件驅動的異步API，使 Java NIO在各種傳輸協議（如TCP/IP，UDP/IP協議等）下快速高效開發。

Apache Mina也稱為：

NIO框架

客戶端/服務端框架（典型的C/S架構）

網絡套接字（networking socket）類庫

事件驅動的異步API(注意：在JDK7中也新增了異步API)

總之：我們簡單理解它是一個封裝底層IO操作，提供高級操作API的通訊框架！

在Mina的官網、以及網上都有比較豐富的文檔了，這里我就稍微簡單說一下Mina的結構和示例代碼。

因為Mina2.X改進了Mina的代碼結構和包結構，降低了使用的復雜性和增強了健壯性，所以使得API發生了比較大的改變，有許多地方已經和Mina1.x不兼容了。

這里使用的是Mina2.0.4

1.Mina的結構

Jva NIO框架 Apache Mina 2.x 簡易入門解析

Mina的通信流程大致如上圖所示，各個組件功能有：
(1.) IoService：這個接口在一個線程上負責套接字的建立，擁有自己的Selector，監
聽是否有連接被建立。

（Mina底層使用JAVA NIO，因此它是典型的使用Reactor模式架構的,采用事件驅動編程 , Mina運行用戶自定義線程模型，可以是單線程、多線程、線程池等 ,

跟JAVA Socket不一樣， Mina是非阻塞的Socket，它內部已經保證了對各個連接(session)的業務和數據的隔離，采用輪詢機制為各個session分配CPU資源，

所以，你就不需要再去考慮不同Socket連接需要用不同的線程去操縱的問題了。)

(2.) IoProcessor：這個接口在另一個線程上負責檢查是否有數據在通道上讀寫，也就是
說它也擁有自己的Selector，這是與我們使用JAVA NIO 編碼時的一個不同之處，
通常在JAVA NIO 編碼中，我們都是使用一個Selector，也就是不區分IoService
與 IoProcessor 兩個功能接口。另外，IoProcessor 負責調用注冊在IoService 上
的過濾器，并在過濾器鏈之后調用IoHandler。

(3.) IoFilter：這個接口定義一組攔截器，這些攔截器可以包括日志輸出、黑名單過濾、
數據的編碼（write 方向）與解碼（read 方向）等功能，其中數據的encode 與 decode
是最為重要的、也是你在使用Mina 時最主要關注的地方。

(4.) IoHandler：這個接口負責編寫業務邏輯，也就是接收、發送數據的地方。

2. Mina編程的大致過程.

2.1 總體流程

建立服務器端的資源：包括 Acceptor的建立，之后為Acceptor配置相應的Filter(可以是Mina自帶的Filter或者自定義的Filter），

之后再配置相應基于事件驅動的處理業務邏輯的IoHandler.

建立客戶端的資源： Mina采用了統一的編程模型，所以建立客戶端的過程和建立服務器端的過程大致上是相似的，不過這里建立的是Connector.

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

下面通過一個簡單的示例程序來進一步理解Mina的運行機制。

該程序實現簡單的即時通訊功能。即，多個客戶端可以同時臉上服務器，并進行類似于聊天室一樣的通信。

2.2.1 建立自定義的TextLineCodecFacotry

為了了解Mina的代碼功能以及運行機制，我們模擬實現了類似Mina自帶TextLineCodecFactory。

該CodecFactory功能是：配合ProtocolCodecFilter 進行對底層數據(binary二進制數據流)和高層數據(特定類型的數據對象信息，例如String)之間的轉換。

這里實現了一個斷行讀取功能，即遇到'\n'的時候，就認為是一個String Line ，將這段數據流封裝成String，之后再交給下一個Filter或者Handler處理。

CodecFactory是一個工廠方法，底層通過一個Decoder和Encoder來提供對數據進行解、編碼的操作,載體是IoBuffer。

（解碼：將二進制數據轉換成高層數據(對象) 編碼：將高層數據(對象)轉換成二進制數據流) )

1）建立Decoder (MyTextLineDecoder)

實現了ProtocolDecoder接口

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

}


}</pre> 

                2）建立Encoder （MyTextLineEncoder)

                        實現了ProtocolEncoder接口

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);

}


}</pre> 

                3）建立MyTextLineCodecFactory

                        實現了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();
}


}</pre>         2.2.2 建立服務器端資源（包括Acceptor的配置、Handler建立) 

                1). 建立自定義IoHandler（MyServerHandleDemo1)

                        實現了IoHandler接口。

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("服務器啟動發生異常，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("服務器成功發送信息: " + 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

}



}</iosession></pre>            2).建立Acceptor ，同時也充當Server端的啟動類 (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("服務器啟動失敗");
    }else{
        System.out.println("服務器啟動成功");
    }
}


}</pre>         2.2.3 建立Client端資源： 

                1）自定義IoHandler(MyClientHandleDemo1)

                        實現IoHandler接口

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("客戶端發了一個信息：" + message.toString());
}


}</pre>                2) 建立Connector   (SimpleMinaClient)
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();
    }

}


}</pre></strong> 

        到這里，基本的Mina通信基礎就建立好了。

        接下來實現一個客戶端的GUI界面，方便實際功能的建立和信息交互的演示。

 

        2.2.4 Client Gui界面的建立。(ChatPanel -通過使用SimpleMinaClient來提供實際通信功能)

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("連接服務器失敗。。。");
    }
}


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("連接已斷開...");
        connected = false;
        dealUIWithFlag();
    }else{
        showMsg("無法斷開連接...");
    }
}



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();
    } 
}


}</strong></pre>3. 運行結果 

        首先啟動服務器端，即運行SimpleMinaServer類 ， 啟動成功時會在控制臺中打印出“服務器啟動成功"

        接下來運行客戶端ChatPanel。






note: 上面只是一個簡單的信息交互，其實使用Mina比較常用的還是在自定義協議處理這塊。
                所以，比較應該注重學習的是Filter這塊。有時間大家可以去看看源碼。 






來自：http://www.cnblogs.com/mailingfeng/archive/2012/02/08/2342522.html

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