Mina入门实例

继续上一篇，这篇主要讲通过mina往B端发送消息，并接受消息，mina是一个网络通信框架，封装了javaNIO，简单易用，网上有很多关于他的介绍，在此不赘述了。

如上篇所介绍，完成功能，需要五个类：

PoolListener：监听，用来在系统启动的时候创建连接；

SessionPool：连接池；

SendHandler：处理类；

CharsetEncoder：编码；

CharsetDecoder：解码：

B为我们提供了6个端口，每个端口可建立3个长连接，因此，在系统时，就要创建长连接，下面是一个监听类：

import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;/** * 初始化连接 * @author yuanfubiao * */public class PoolListener implements ServletContextListener {@Overridepublic void contextDestroyed(ServletContextEvent sce) {}@Overridepublic void contextInitialized(ServletContextEvent sce) {String nds_ip = sce.getServletContext().getInitParameter("nds_ip");String nds_ports = sce.getServletContext().getInitParameter("nds_ports");SessionPool pool = new SessionPool();try {pool.init(nds_ip, nds_ports);} catch (Exception e) {e.printStackTrace();}}}

下面是监听配置，是配置在web.xml中：

    <display-name>Apache-Axis2</display-name>    <context-param>    <param-name>nds_ip</param-name>    <param-value>XX.XXX.XXX.XXX</param-value>    </context-param>    <context-param>    <param-name>nds_ports</param-name>    <param-value>12210,12211,12212,12213,12214,12215</param-value>    </context-param>    <listener>    <listener-class>cn.net.easyway.nds.PoolListener</listener-class>    </listener>

下面是自己维护的一个连接池，同样使用并发包中的ConcurrentHashMap实现，他也是线程安全的，代码如下：

import java.net.InetSocketAddress;import java.util.HashMap;import java.util.Map;import java.util.concurrent.ConcurrentHashMap;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.apache.mina.core.future.ConnectFuture;import org.apache.mina.core.service.IoConnector;import org.apache.mina.core.session.IoSession;import org.apache.mina.filter.codec.ProtocolCodecFilter;import org.apache.mina.transport.socket.nio.NioSocketConnector;public class SessionPool {private static Log logger = LogFactory.getLog(SessionPool.class);private static int connNum = 0;private static String ip = null;private static Map<String,Integer> connNumPorts = new HashMap<String, Integer>();private static ConcurrentHashMap<String, IoSession> pool = new ConcurrentHashMap<String, IoSession>();/** * 初始化：读取配置文件，创建长连接 * @throws Exception  */public void init(String nds_ip,String nds_ports) throws Exception{String[] ports = nds_ports.split(",");ip = nds_ip;for(int i=0;i<ports.length;i++){int port = Integer.parseInt(ports[i]);ConnectFuture future = null;for(int j=0;j<3;j++){String connNum = this.getConnNums();logger.info("创建连接号---->>>>>" + connNum);connNumPorts.put(connNum, port);future = SessionPool.createConnect(ip, port);if(future.isConnected()){logger.info("创建连接------->" + future.getSession());pool.put(connNum, future.getSession());}else{logger.error("连接创建错误,请检查IP和端口配置！" + future);}}}}/** * 获取一个连接 * @param num * @return */public static IoSession  getSession(String strNum){logger.info("IP端口号：" + ip + "连接序列号：" + strNum + "端口号：" + connNumPorts.get(strNum));IoSession session = pool.get(strNum);if(null == session || !session.isClosing()){ConnectFuture newConn = createConnect(ip, connNumPorts.get(strNum));if(!newConn.isConnected()){newConn =  createConnect(ip,connNumPorts.get(strNum));}session = newConn.getSession();pool.replace(strNum, session);}return session;}/** * 创建连接 * @param ip * @param port * @return */private static ConnectFuture createConnect(String strIp,int intPort){IoConnector connector = new NioSocketConnector();connector.getFilterChain().addLast("codec",new ProtocolCodecFilter(new CharsetCodecFactory()));connector.setHandler(new SendHandler());ConnectFuture future = connector.connect(new InetSocketAddress(strIp,intPort));connector.getSessionConfig().setReadBufferSize(128);future.awaitUninterruptibly();return future;}/** * 生成连接序列号 * @return */private synchronized String getConnNums(){if(18 == connNum){connNum = 0;}connNum++;return String.format("%02x", connNum);}}

因此，在项目启动的时候就会有18个连接自动创建，并放在pool中等待我们的使用。下面是业务处理类，需要继承IoHandlerAdapter类，并且实现以下几个方法：

import nds.framework.security.NDSMD5;import org.apache.commons.codec.binary.Hex;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.apache.mina.core.service.IoHandlerAdapter;import org.apache.mina.core.session.IdleStatus;import org.apache.mina.core.session.IoSession;import cm.custom.service.reception.RecResponse;import cm.custom.service.reception.ReceptionResponseServiceStub;/** * 业务处理 * @author yuanfubiao * */public class SendHandler extends IoHandlerAdapter {private static Log logger = LogFactory.getLog(SendHandler.class);@Overridepublic void exceptionCaught(IoSession session, Throwable cause)throws Exception {logger.error("连接出错", cause);}@Override/** * 设置空闲时间 */public void sessionCreated(IoSession session) throws Exception {session.getConfig().setIdleTime(IdleStatus.BOTH_IDLE, 60);}/** * 接受到消息后，通过WS发送给用户管理系统 */@Overridepublic void messageReceived(IoSession session, Object message)throws Exception {String result = message.toString().trim();String temp = result.substring(0, result.length()-16).trim();logger.info("接受到的数据：" + result);//验证签名String signature = null;String securityKey = "12345678";try {byte binSignature[] = NDSMD5.signPacket(temp.getBytes(), securityKey);signature = new String(Hex.encodeHex(binSignature));} catch (Exception e) {e.printStackTrace();}String packet = temp + signature.toUpperCase().trim();if(!result.equalsIgnoreCase(packet)){logger.error("数字签名不正确！错误指令：" + result);return;}logger.info("接受到的数据：" + packet);RecResponse res = new RecResponse();res.setResponse(temp);ReceptionResponseServiceStub stub = new ReceptionResponseServiceStub();stub.recResponse(res);}/** * 连接空闲时，发送心跳包 */@Overridepublic void sessionIdle(IoSession session, IdleStatus status)throws Exception {if(status == IdleStatus.BOTH_IDLE){session.write("heartbeat");}}}

一般我们在写socket程序时，用阻塞的方式读取消息，一般是根据消息换行符或者特殊字符，或者对方关闭流来证明一条信息读取完成，在mina中，有默认的编解码方式，但也可以自定义，比如以长度来判断一条消息是否读取完毕：

编码

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.ProtocolEncoderAdapter;import org.apache.mina.filter.codec.ProtocolEncoderOutput;/** * 编码 * @author yuanfubiao * */public class CharsetEncoder extends ProtocolEncoderAdapter{private final static Charset charset = Charset.forName("utf-8");@Overridepublic void encode(IoSession session, Object message, ProtocolEncoderOutput out)throws Exception {IoBuffer buff = IoBuffer.allocate(100).setAutoExpand(true);buff.putString(message.toString(), charset.newEncoder());buff.flip();out.write(buff);}}

解码

import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;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;/** * 解码 * @author yuanfubiao * */public class CharsetDecoder extends CumulativeProtocolDecoder{private static Log logger = LogFactory.getLog(CharsetDecoder.class);@Overrideprotected boolean doDecode(IoSession session, IoBuffer in,ProtocolDecoderOutput out) throws Exception {if(in.remaining() >= 9){ //心跳为最小传输长度byte[] headBytes = new byte[in.limit()];logger.info("接收到消息" + headBytes.toString());in.get(headBytes, 0, 9);String head = new String(headBytes).trim();if("heartbeat".equalsIgnoreCase(head)){return true;}int lenPack = Integer.parseInt(head.substring(5, 9), 16)-9;if(in.remaining() == lenPack){ //验证消息长度byte[] bodyBytes = new byte[in.limit()];in.get(bodyBytes,0,lenPack);String body = new String(bodyBytes);out.write(head.trim()+body.trim());return true;}in.flip();return false;}return false;}}

源码下载：http://download.csdn.net/detail/stubbornpotatoes/7438435

关于mina发现一个系列好文章：http://xxgblog.com/2014/10/16/mina-netty-twisted-10/