Socket编程及mina框架简单示例

要实现客户端与服务器的长连接，可以使用socket的方式连接服务器与客户端。在这篇文章中，将用原生的方式实现socket的服务器端和客户端，然后用Mina框架再实现一次。
原生方式上：
客户端可实现如下：
SocketClient:

package socketClient;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.net.Socket;public class SocketClient {    public int port = 9898;    public String hostAddress = "127.0.0.1";    public static void main(String[] args) {        SocketClient client = new SocketClient();        client.start();    }    private void start() {        BufferedReader inputReader = null;        OutputStreamWriter output = null;        Socket socket = null;        try {            socket = new Socket(hostAddress, port);            inputReader = new BufferedReader(new InputStreamReader(System.in));            output = new OutputStreamWriter(socket.getOutputStream());            String inputContent;            int count = 0;            while (!(inputContent = inputReader.readLine()).equals("bye")) {                output.write(inputContent);                    output.write("\n");                output.flush();                getServerMsg(socket);            }        } catch (IOException e) {            e.printStackTrace();        } finally {            try {                output.close();                inputReader.close();                socket.close();            } catch (IOException e) {                e.printStackTrace();            }        }    }    private void getServerMsg(Socket socket) {        new Thread(new Runnable() {            @Override            public void run() {                BufferedReader reader = null;                try {                    reader = new BufferedReader(new InputStreamReader(                            socket.getInputStream()));                    String serverMsg;                    while ((serverMsg = reader.readLine()) != null) {                        System.out.println("server say: " + serverMsg);                    }                } catch (IOException e) {                    e.printStackTrace();                } finally {                    try {                        reader.close();                    } catch (IOException e) {                        e.printStackTrace();                    }                }            }        }).start();    }}

服务器端：

package com.socket.tra;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.net.ServerSocket;import java.net.Socket;public class SocketServer {    public static void main(String[] args) {        SocketServer server = new SocketServer();        server.startServer();    }    private void startServer() {        ServerSocket serverSocket = null;        Socket socket = null;        try {            serverSocket = new ServerSocket(9898);            while (true) {                socket = serverSocket.accept();                System.out.println(socket.hashCode() + " is connect");                connect(socket);            }        } catch (IOException e) {            e.printStackTrace();        }    }    private void connect(final Socket socket) {        new Thread(new Runnable() {            public void run() {                BufferedReader reader = null;                OutputStreamWriter writer = null;                try {                    reader = new BufferedReader(new InputStreamReader(                            socket.getInputStream()));                    writer = new OutputStreamWriter(socket.getOutputStream());                    String msg;                    while ((msg = reader.readLine()) != null) {                        System.out.println(socket.hashCode()+"say: "+msg);                        writer.write(msg + "\n");                        writer.flush();                    }                } catch (IOException e) {                    e.printStackTrace();                } finally {                    try {                        writer.close();                        reader.close();                        socket.close();                    } catch (IOException e) {                        e.printStackTrace();                    }                }            }        }).start();    }}

这是socket基本的用法，但在实际开发中，我们一般用封装好的框架来实现，Apache mina就是能够帮助用户开发高性能和高伸缩性网络应用程序的框架。它通过Java nio技术基于TCP/IP和UDP/IP协议提供了抽象的、事件驱动的、异步的API。
具体用法可以去官网了解下，这里提供一个简单的使用示例，实现跟上面原生方法同样的功能。
版本一：
服务器端:

package com.socket;import java.io.IOException;import java.net.InetSocketAddress;import org.apache.mina.filter.codec.ProtocolCodecFilter;import org.apache.mina.filter.codec.textline.TextLineCodecFactory;import org.apache.mina.transport.socket.nio.NioSocketAcceptor;public class Main {    public static int port = 9898;    public static void main(String[] args) {        NioSocketAcceptor acceptor = new NioSocketAcceptor();        try {            //设置handler            acceptor.setHandler(new MyHandler());            //设置过滤器            acceptor.getFilterChain().addLast("codec", new ProtocolCodecFilter(new TextLineCodecFactory()));            //绑定端口号            acceptor.bind(new InetSocketAddress(port));        } catch (IOException e) {            e.printStackTrace();        }    }}

MyHandler:

package com.socket;import org.apache.mina.core.service.IoHandler;import org.apache.mina.core.session.IdleStatus;import org.apache.mina.core.session.IoSession;public class MyHandler implements IoHandler {    public void exceptionCaught(IoSession arg0, Throwable arg1)            throws Exception {        System.out.println("exception");    }    public void inputClosed(IoSession arg0) throws Exception {        System.out.println("inputClosed");    }    public void messageReceived(IoSession arg0, Object arg1) throws Exception {        String msg = (String) arg1;        System.out.println("messageReceived server: " + msg);        arg0.write(msg);    }    public void messageSent(IoSession arg0, Object arg1) throws Exception {        System.out.println("messageSent");    }    public void sessionClosed(IoSession arg0) throws Exception {        System.out.println("sessionClosed "+arg0.hashCode());    }    public void sessionCreated(IoSession arg0) throws Exception {        System.out.println("sessionCreated "+arg0.hashCode());    }    public void sessionIdle(IoSession arg0, IdleStatus arg1) throws Exception {        System.out.println("sessionIdle "+arg0.hashCode()+" , "+arg1);    }    public void sessionOpened(IoSession arg0) throws Exception {        System.out.println("sessionOpened "+arg0.hashCode());    }}

客户端：

package socketClient.mina;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.net.InetSocketAddress;import java.net.Socket;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.TextLineCodecFactory;import org.apache.mina.transport.socket.nio.NioSocketConnector;public class SocketClient {    public int port = 9898;    public String hostAddress = "127.0.0.1";    public static void main(String[] args) throws IOException {        NioSocketConnector connector = new NioSocketConnector();        connector.setHandler(new MyClientHandler());        connector.getFilterChain().addLast("codec", new ProtocolCodecFilter(new TextLineCodecFactory()));        ConnectFuture future = connector.connect(new InetSocketAddress("127.0.0.1", 9898));        future.awaitUninterruptibly();//等待连接        IoSession session = future.getSession();        BufferedReader inputReader = new BufferedReader(new InputStreamReader(System.in));        String inputContent;        while (!(inputContent = inputReader.readLine()).equals("bye")) {            session.write(inputContent);        }    }}

MyClientHandler:

package socketClient.mina;import org.apache.mina.core.service.IoHandler;import org.apache.mina.core.session.IdleStatus;import org.apache.mina.core.session.IoSession;public class MyClientHandler implements IoHandler {    public void exceptionCaught(IoSession arg0, Throwable arg1)            throws Exception {        System.out.println(arg1.getCause());    }    public void inputClosed(IoSession arg0) throws Exception {//      System.out.println("inputClosed");    }    public void messageReceived(IoSession arg0, Object arg1) throws Exception {        String msg = (String) arg1;        System.out.println("client messageReceived: " + msg);    }    public void messageSent(IoSession arg0, Object arg1) throws Exception {        System.out.println("client messageSent->" + (String)arg1);    }    public void sessionClosed(IoSession arg0) throws Exception {        System.out.println("sessionClosed "+arg0.hashCode());    }    public void sessionCreated(IoSession arg0) throws Exception {        System.out.println("sessionCreated "+arg0.hashCode());    }    public void sessionIdle(IoSession arg0, IdleStatus arg1) throws Exception {        System.out.println("sessionIdle "+arg0.hashCode()+" , "+arg1);    }    public void sessionOpened(IoSession arg0) throws Exception {        System.out.println("sessionOpened "+arg0.hashCode());    }}

版本一使用框架写好的TextLineCodecFactory来解析字符串，在实际实用场合中，往往要自定义解析功能，因此版本二自己写一个字符串解析功能。
版本二：
服务器端：
Main: 主函数
MyDecoder: 实现数据的解码
MyEncoder: 实现数据的编码
MyHandler:
MyProtocolFactory: 生成编码和解码器
MyCumulativeEncoder: 实现数据的编码，可将服务器数据进行缓存，防止数据丢失

Main:

package com.socket.r1;import java.io.IOException;import java.net.InetSocketAddress;import org.apache.mina.core.session.IdleStatus;import org.apache.mina.filter.codec.ProtocolCodecFilter;import org.apache.mina.filter.codec.textline.TextLineCodecFactory;import org.apache.mina.filter.logging.LoggingFilter;import org.apache.mina.transport.socket.nio.NioSocketAcceptor;public class Main {    public static int port = 9898;    public static void main(String[] args) {        NioSocketAcceptor acceptor = new NioSocketAcceptor();        try {            acceptor.setHandler(new MyHandler());            acceptor.getFilterChain().addLast("logger", new LoggingFilter());            acceptor.getFilterChain().addLast("codec", new ProtocolCodecFilter(new MyProtocolCodecFactory()));            acceptor.getSessionConfig().setIdleTime(IdleStatus.BOTH_IDLE, 125);            acceptor.bind(new InetSocketAddress(port));             } catch (IOException e) {            e.printStackTrace();        }    }}

MyDecoder:

package com.socket.r1;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 MyDecoder implements ProtocolDecoder {    public void decode(IoSession session, IoBuffer in, ProtocolDecoderOutput output)            throws Exception {        //记录字符流的读取位置        int startPosition = in.position();        while(in.hasRemaining()){            byte b = in.get();            if(b == '\n'){                int curPosition = in.position();                //记录字符流的末位置                int limit = in.limit();                //将读取指针设置为初始位置                in.position(startPosition);                //将结束位置设置为当前读取位置                in.limit(curPosition);                IoBuffer buf = in.slice();                byte[] bytes = new byte[buf.limit()];                //将截取的内容放进bytes数组                buf.get(bytes);                String str = new String(bytes);                output.write(str);                in.position(curPosition);                in.limit(limit);            }        }    }    public void dispose(IoSession arg0) throws Exception {        System.out.println("dispose" + arg0.hashCode());    }    public void finishDecode(IoSession arg0, ProtocolDecoderOutput arg1)            throws Exception {        System.out.println("finishDecode" + arg0.hashCode());    }}

MyEncoder:

package com.socket.r1;import java.nio.charset.Charset;import java.nio.charset.CharsetEncoder;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;public class MyEncoder implements ProtocolEncoder {    public void dispose(IoSession arg0) throws Exception {        System.out.println("dispose" + arg0.hashCode());        }    public void encode(IoSession arg0, Object msg, ProtocolEncoderOutput output)            throws Exception {        String s= null;        if(msg instanceof String){            s = (String) msg;        }        if(s!=null){            CharsetEncoder charsetEncoder = (CharsetEncoder) arg0.getAttribute("encoder");            if(charsetEncoder ==null){                charsetEncoder = Charset.defaultCharset().newEncoder();                arg0.setAttribute("encoder",charsetEncoder);            }            IoBuffer ioBuffer = IoBuffer.allocate(s.length());            ioBuffer.setAutoExpand(true);            ioBuffer.putString(s, charsetEncoder);            ioBuffer.flip();            output.write(ioBuffer);        }    }}

MyHandler跟版本一的一样，这里就不贴代码了。
MyCumulativeDecoder ：

package com.socket.r1;import org.apache.mina.core.buffer.IoBuffer;import org.apache.mina.core.session.IoSession;import org.apache.mina.filter.codec.CumulativeProtocolDecoder;import org.apache.mina.filter.codec.ProtocolDecoderOutput;public class MyCumulativeDecoder extends CumulativeProtocolDecoder {    /**     * 确认读取完成时return true     */    @Override    protected boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput output)            throws Exception {        int startPosition = in.position();        while(in.hasRemaining()){            byte b = in.get();            if(b == '\n'){                int curPosition = in.position();                int limit = in.limit();                in.position(startPosition);                in.limit(curPosition);                IoBuffer buf = in.slice();                byte[] bytes = new byte[buf.limit()];                buf.get(bytes);                String str = new String(bytes);                output.write(str);                in.position(curPosition);                in.limit(limit);                return true;            }        }        //取消此次的读取，将读取位置重置        in.position(startPosition);        return false;    }}

MyProtocolCodecFactory ：

package com.socket.r1;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 MyProtocolCodecFactory implements ProtocolCodecFactory {//  private MyDecoder decoder;    private MyCumulativeDecoder decoder;    private MyEncoder encoder;    public MyProtocolCodecFactory() {//      decoder = new MyDecoder();        decoder = new MyCumulativeDecoder();        encoder = new MyEncoder();    }    public ProtocolDecoder getDecoder(IoSession arg0) throws Exception {        return decoder;    }    public ProtocolEncoder getEncoder(IoSession arg0) throws Exception {        return encoder;    }}