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最近使用Mina開發(fā)一個(gè)Java的NIO服務(wù)端程序，因此也特意學(xué)習(xí)了Apache的這個(gè)Mina框架。 首先，Mina是個(gè)什么東西？看下官方網(wǎng)站（http://mina./）對(duì)它的解釋： Apache的Mina（Multipurpose Infrastructure Networked Applications）是一個(gè)網(wǎng)絡(luò)應(yīng)用框架，可以幫助用戶開發(fā)高性能和高擴(kuò)展性的網(wǎng)絡(luò)應(yīng)用程序；它提供了一個(gè)抽象的、事件驅(qū)動(dòng)的異步API，使Java NIO在各種傳輸協(xié)議（如TCP/IP，UDP/IP協(xié)議等）下快速高效開發(fā)。 Apache Mina也稱為： - NIO框架
- 客戶端/服務(wù)端框架（典型的C/S架構(gòu)）
- 網(wǎng)絡(luò)套接字（networking socket）類庫
- 事件驅(qū)動(dòng)的異步API(注意：在JDK7中也新增了異步API)
總之：我們簡(jiǎn)單理解它是一個(gè)封裝底層IO操作，提供高級(jí)操作API的通訊框架！ 在Mina的官網(wǎng)、以及網(wǎng)上都有比較豐富的文檔了，這里我就稍微簡(jiǎn)單說一下Mina的結(jié)構(gòu)和示例代碼。 因?yàn)镸ina2.X改進(jìn)了Mina的代碼結(jié)構(gòu)和包結(jié)構(gòu)，降低了使用的復(fù)雜性和增強(qiáng)了健壯性，所以使得API發(fā)生了比較大的改變，有許多地方已經(jīng)和Mina1.x不兼容了。 這里使用的是Mina2.0.4 1.Mina的結(jié)構(gòu) 
Mina的通信流程大致如上圖所示，各個(gè)組件功能有：
(1.) IoService：這個(gè)接口在一個(gè)線程上負(fù)責(zé)套接字的建立，擁有自己的Selector，監(jiān)
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(gòu)的,采用事件驅(qū)動(dòng)編程 , Mina運(yùn)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(nèi)部已經(jīng)保證了對(duì)各個(gè)連接(session)的業(yè)務(wù)和數(shù)據(jù)的隔離，采用輪詢機(jī)制為各個(gè)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(gè)接口在另一個(gè)線程上負(fù)責(zé)檢查是否有數(shù)據(jù)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(shí)的一個(gè)不同之處，
通常在JAVA NIO 編碼中，我們都是使用一個(gè)Selector，也就是不區(qū)分IoService
與 IoProcessor 兩個(gè)功能接口。另外，IoProcessor 負(fù)責(zé)調(diào)用注冊(cè)在IoService 上
的過濾器，并在過濾器鏈之后調(diào)用IoHandler。
(3.) IoFilter：這個(gè)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(shù)據(jù)的編碼（write 方向）與解碼（read 方向）等功能，其中數(shù)據(jù)的encode 與 decode
是最為重要的、也是你在使用Mina 時(shí)最主要關(guān)注的地方。
(4.) IoHandler：這個(gè)接口負(fù)責(zé)編寫業(yè)務(wù)邏輯，也就是接收、發(fā)送數(shù)據(jù)的地方。
2. Mina編程的大致過程. 2.1 總體流程 建立服務(wù)器端的資源： 包括 Acceptor的建立，之后為Acceptor配置相應(yīng)的Filter(可以是Mina自帶的Filter或者自定義的Filter）， 之后再配置相應(yīng)基于事件驅(qū)動(dòng)的處理業(yè)務(wù)邏輯的IoHandler. 建立客戶端的資源： Mina采用了統(tǒng)一的編程模型，所以建立客戶端的過程和建立服務(wù)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(gè)簡(jiǎn)單的示例程序來進(jìn)一步理解Mina的運(yùn)行機(jī)制。 該程序?qū)崿F(xiàn)簡(jiǎn)單的即時(shí)通訊功能。 即，多個(gè)客戶端可以同時(shí)臉上服務(wù)器，并進(jìn)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(yùn)行機(jī)制，我們模擬實(shí)現(xiàn)了類似Mina自帶TextLineCodecFactory。 該CodecFactory功能是： 配合ProtocolCodecFilter 進(jìn)行對(duì)底層數(shù)據(jù)(binary二進(jìn)制數(shù)據(jù)流)和高層數(shù)據(jù)(特定類型的數(shù)據(jù)對(duì)象信息，例如String)之間的轉(zhuǎn)換。 這里實(shí)現(xiàn)了一個(gè)斷行讀取功能，即遇到'\n'的時(shí)候，就認(rèn)為是一個(gè)String Line ， 將這段數(shù)據(jù)流封裝成String，之后再交給下一個(gè)Filter或者Handler處理。 CodecFactory是一個(gè)工廠方法，底層通過一個(gè)Decoder和Encoder來提供對(duì)數(shù)據(jù)進(jìn)行解、編碼的操作,載體是IoBuffer。 （解碼：將二進(jìn)制數(shù)據(jù)轉(zhuǎn)換成高層數(shù)據(jù)(對(duì)象) 編碼：將高層數(shù)據(jù)(對(duì)象)轉(zhuǎn)換成二進(jìn)制數(shù)據(jù)流) ) 1）建立Decoder (MyTextLineDecoder) 實(shí)現(xiàn)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
}
} 2）建立Encoder （MyTextLineEncoder) 實(shí)現(xiàn)了ProtocolEncoder接口 View Codepackage 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);
}
} 3）建立MyTextLineCodecFactory 實(shí)現(xiàn)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();
}
}
2.2.2 建立服務(wù)器端資源（包括Acceptor的配置、Handler建立)
1). 建立自定義IoHandler（MyServerHandleDemo1) 實(shí)現(xiàn)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("服務(wù)器啟動(dòng)發(fā)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(wù)器成功發(fā)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 ，同時(shí)也充當(dāng)Server端的啟動(dòng)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(wù)器啟動(dòng)失敗");
}else{
System.out.println("服務(wù)器啟動(dòng)成功");
}
}
}
2.2.3 建立Client端資源：
1）自定義IoHandler(MyClientHandleDemo1) 實(shí)現(xiàn)IoHandler接口 View Codepackage 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(fā)了一個(gè)信息：" + message.toString());
}
} 2) 建立Connector (SimpleMinaClient) View Codepackage 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();
}
}
} 到這里，基本的Mina通信基礎(chǔ)就建立好了。 接下來實(shí)現(xiàn)一個(gè)客戶端的GUI界面，方便實(shí)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(shí)際通信功能) View Codepackage 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(wù)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();
}
}
}
3. 運(yùn)行結(jié)果
首先啟動(dòng)服務(wù)器端，即運(yùn)行SimpleMinaServer類 ， 啟動(dòng)成功時(shí)會(huì)在控制臺(tái)中打印出“服務(wù)器啟動(dòng)成功" 接下來運(yùn)行客戶端ChatPanel。
note: 上面只是一個(gè)簡(jiǎn)單的信息交互，其實(shí)使用Mina比較常用的還是在自定義協(xié)議處理這塊。
所以，比較應(yīng)該注重學(xué)習(xí)的是Filter這塊。有時(shí)間大家可以去看看源碼。
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