引言：
Mina是一个网络通信应用框架，也就是说，它主要是对基于TCP/IP、UDP/IP
协议栈的通信框架（当然，也可以提供JAVA 对象的序列化服务、虚拟机管道通信服务等），
Mina 可以帮助我们快速开发高性能、高扩展性的网络通信应用，Mina 提供了事件驱动、异
步（Mina 的异步IO 默认使用的是JAVA NIO 作为底层支持）操作的编程模型。Mina的相关组件IoService，IoProcessor,IoFilter,IoHanler,IoBuffer的含义，可以搜索相关文章，这里不再赘述。
今天我们来看一个简单的TCP通信实例,实例所用MINA版本为2.0.16：
server：
package mina.tcp.main;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.charset.Charset;
import org.apache.mina.core.filterchain.DefaultIoFilterChainBuilder;
import org.apache.mina.core.service.IoAcceptor;
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.LoggingFilter;
import org.apache.mina.transport.socket.SocketSessionConfig;
import org.apache.mina.transport.socket.nio.NioSocketAcceptor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import mina.tcp.handler.SimpleServerHandler;
/**
* simple Server-TextLineCodecFactory
* @author donald
* 2017年5月19日
* 上午8:59:37
*/
public class SimpleServer {
private static final Logger log = LoggerFactory.getLogger(SimpleServer.class);
private static final String ip = "192.168.126.135";
private static final int port = 9122;
private static final int readBufferSize = 2048;
private static final int idleTime = 10;
private static final Charset charset = Charset.forName("UTF-8");
public static void main(String[] args) throws IOException {
IoAcceptor acceptor=new NioSocketAcceptor();
//配置socket会话
SocketSessionConfig socketSessionConfig = (SocketSessionConfig) acceptor.getSessionConfig();
socketSessionConfig.setReadBufferSize(readBufferSize);
socketSessionConfig.setIdleTime(IdleStatus.BOTH_IDLE,idleTime);
//配置过滤器
DefaultIoFilterChainBuilder defaultIoFilterChainBuilder = acceptor.getFilterChain();
LoggingFilter loggingFilter = new LoggingFilter();
defaultIoFilterChainBuilder.addLast("loggingFilter", loggingFilter);
TextLineCodecFactory textLineCodecFactory =
new TextLineCodecFactory(charset,LineDelimiter.WINDOWS.getValue(),
LineDelimiter.WINDOWS.getValue());
ProtocolCodecFilter protocolCodecFilter = new ProtocolCodecFilter(textLineCodecFactory);
defaultIoFilterChainBuilder.addLast("protocolCodecFilter",protocolCodecFilter);
//配置NioSocketAcceptor处理器
SimpleServerHandler simpleServerHandler = new SimpleServerHandler();
acceptor.setHandler(simpleServerHandler);
InetSocketAddress inetSocketAddress = new InetSocketAddress(ip,port);
acceptor.bind(inetSocketAddress);
log.info("=========SimpleServer is start============");
}
}
server handler：
package mina.tcp.handler;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.service.IoHandlerAdapter;
import org.apache.mina.core.session.IdleStatus;
import org.apache.mina.core.session.IoSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* simple server handler
* @author donald
* 2017年5月19日
* 下午1:13:45
*/
public class SimpleServerHandler extends IoHandlerAdapter {
private final static Logger log = LoggerFactory.getLogger(SimpleServerHandler.class);
private static final CharsetEncoder charsetEncoder= Charset.forName("UTF-8").newEncoder();
private static final CharsetDecoder charsetDecoder= Charset.forName("UTF-8").newDecoder();
public void messageReceived(IoSession session, Object message) throws Exception {
String msg = (String) message;
log.info("=========The message received from Client is:" + msg);
//收到客户端发送的关闭会话命令
/*if(msg.equals("quit")){
session.closeNow();
}*/
IoBuffer buffer = IoBuffer.allocate(1024);
buffer.putString("Hello Client...\r\nI'm Server...\r\nserver test...", charsetEncoder);
buffer.flip();
session.write(buffer);
}
@Override
public void sessionClosed(IoSession session) throws Exception {
log.debug("=========Session Closed...");
}
@Override
public void sessionCreated(IoSession session) throws Exception {
log.debug("=========Session Created...");
}
@Override
public void sessionIdle(IoSession session, IdleStatus status) throws Exception {
log.debug(session + "=========Session Idle...");
}
@Override
public void sessionOpened(IoSession session) throws Exception {
log.debug("=========Session Opened...");
}
@Override
public void exceptionCaught(IoSession session, Throwable cause) throws Exception {
log.error(cause.getMessage());
cause.printStackTrace();
session.closeNow();
}
@Override
public void messageSent(IoSession session, Object message) throws Exception {
log.debug("=========messageSent...");
}
}
client：
package mina.tcp.main;
import java.net.InetSocketAddress;
import java.nio.charset.Charset;
import org.apache.mina.core.filterchain.DefaultIoFilterChainBuilder;
import org.apache.mina.core.service.IoConnector;
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.LoggingFilter;
import org.apache.mina.transport.socket.nio.NioSocketConnector;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import mina.tcp.handler.SimpleClientHandler;
/**
* Simple Client - TextLineCodecFactory
* @author donald
* 2017年5月19日
* 下午1:04:10
*/
public class SimpleClient {
private static final Logger log = LoggerFactory.getLogger(SimpleClient.class);
private static final String ip = "192.168.126.135";
private static final int port = 9122;
private static final int connectTimeoutMillis = 30000;
private static final Charset charset = Charset.forName("UTF-8");
public static void main(String[] args) {
IoConnector connector=new NioSocketConnector();
connector.setConnectTimeoutMillis(connectTimeoutMillis);
//配置过滤器
DefaultIoFilterChainBuilder defaultIoFilterChainBuilder = connector.getFilterChain();
LoggingFilter loggingFilter = new LoggingFilter();
defaultIoFilterChainBuilder.addLast("loggingFilter", loggingFilter);
TextLineCodecFactory textLineCodecFactory =
new TextLineCodecFactory(charset,LineDelimiter.WINDOWS.getValue(),
LineDelimiter.WINDOWS.getValue());
ProtocolCodecFilter protocolCodecFilter = new ProtocolCodecFilter(textLineCodecFactory);
defaultIoFilterChainBuilder.addLast("protocolCodecFilter",protocolCodecFilter);
//配置NioSocketConnector处理器
SimpleClientHandler simpleClientHandler = new SimpleClientHandler();
connector.setHandler(simpleClientHandler);
InetSocketAddress inetSocketAddress = new InetSocketAddress(ip,port);
connector.connect(inetSocketAddress);
log.info("=========SimpleClient is start============");
}
}
client handler：
package mina.tcp.handler;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.service.IoHandlerAdapter;
import org.apache.mina.core.session.IdleStatus;
import org.apache.mina.core.session.IoSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* simple client handler
* @author donald
* 2017年5月19日
* 下午1:10:12
*/
public class SimpleClientHandler extends IoHandlerAdapter {
private final static Logger log = LoggerFactory.getLogger(SimpleClientHandler.class);
private static final CharsetEncoder charsetEncoder= Charset.forName("UTF-8").newEncoder();
private static final CharsetDecoder charsetDecoder= Charset.forName("UTF-8").newDecoder();
public void messageReceived(IoSession session, Object message) throws Exception {
String msg = (String) message;
log.info("=========The message received from Server is:" + msg);
}
@Override
public void sessionCreated(IoSession session) throws Exception {
log.debug("=========Session Created...");
}
@Override
public void sessionOpened(IoSession session) throws CharacterCodingException {
IoBuffer buffer = IoBuffer.allocate(1024);
buffer.putString("Hello Server...\r\nI'm Client...\r\nclient test...", charsetEncoder);
buffer.flip();
session.write(buffer);
//我们可以在这里发送一个quit命令，当Server接受到quit命令时，关闭会话
/*buffer.clear();
buffer.putString("quit\r\n", charsetEncoder);
buffer.flip();
session.write(buffer);*/
}
@Override
public void sessionIdle(IoSession session, IdleStatus status) throws Exception {
log.debug(session + "=========Session Idle...");
}
@Override
public void exceptionCaught(IoSession session, Throwable cause) throws Exception {
log.error(cause.getMessage());
cause.printStackTrace();
session.closeNow();
}
@Override
public void messageSent(IoSession session, Object message) throws Exception {
log.debug("=========messageSent...");
}
@Override
public void sessionClosed(IoSession session) throws Exception {
log.debug("=========Session Closed...");
}
}
本实例中的handler的继承IoHandlerAdapter，在实际开发中，我们不需要实现所有方法，我们只需要实现关注的方法即可比如sessionOpened，
messageReceived，exceptionCaught，sessionClosed。
启动server，client控制台输出：
server：
[INFO ] 2017-05-21 10:46:31 mina.tcp.main.SimpleServer =========SimpleServer is start============
[INFO ] 2017-05-21 10:46:43 org.apache.mina.filter.logging.LoggingFilter CREATED
[DEBUG] 2017-05-21 10:46:43 mina.tcp.handler.SimpleServerHandler =========Session Created...
[INFO ] 2017-05-21 10:46:43 org.apache.mina.filter.logging.LoggingFilter OPENED
[DEBUG] 2017-05-21 10:46:43 mina.tcp.handler.SimpleServerHandler =========Session Opened...
[INFO ] 2017-05-21 10:46:43 org.apache.mina.filter.logging.LoggingFilter RECEIVED: HeapBuffer[pos=0 lim=46 cap=2048: 48 65 6C 6C 6F 20 53 65 72 76 65 72 2E 2E 2E 0D...]
[DEBUG] 2017-05-21 10:46:43 org.apache.mina.filter.codec.ProtocolCodecFilter Processing a MESSAGE_RECEIVED for session 1
[INFO ] 2017-05-21 10:46:43 mina.tcp.handler.SimpleServerHandler =========The message received from Client is:Hello Server...
[INFO ] 2017-05-21 10:46:43 mina.tcp.handler.SimpleServerHandler =========The message received from Client is:I'm Client...
[INFO ] 2017-05-21 10:46:43 org.apache.mina.filter.logging.LoggingFilter SENT: HeapBuffer[pos=0 lim=46 cap=1024: 48 65 6C 6C 6F 20 43 6C 69 65 6E 74 2E 2E 2E 0D...]
[DEBUG] 2017-05-21 10:46:43 mina.tcp.handler.SimpleServerHandler =========messageSent...
[INFO ] 2017-05-21 10:46:43 org.apache.mina.filter.logging.LoggingFilter SENT: HeapBuffer[pos=0 lim=46 cap=1024: 48 65 6C 6C 6F 20 43 6C 69 65 6E 74 2E 2E 2E 0D...]
[DEBUG] 2017-05-21 10:46:43 mina.tcp.handler.SimpleServerHandler =========messageSent...
[INFO ] 2017-05-21 10:46:53 org.apache.mina.filter.logging.LoggingFilter IDLE
[DEBUG] 2017-05-21 10:46:53 mina.tcp.handler.SimpleServerHandler (0x00000001: nio socket, server, /192.168.126.135:60519 => /192.168.126.135:9122)=========Session Idle...
client：
[INFO ] 2017-05-21 10:46:43 mina.tcp.main.SimpleClient =========SimpleClient is start============
[INFO ] 2017-05-21 10:46:43 org.apache.mina.filter.logging.LoggingFilter CREATED
[DEBUG] 2017-05-21 10:46:43 mina.tcp.handler.SimpleClientHandler =========Session Created...
[INFO ] 2017-05-21 10:46:43 org.apache.mina.filter.logging.LoggingFilter OPENED
[INFO ] 2017-05-21 10:46:43 org.apache.mina.filter.logging.LoggingFilter SENT: HeapBuffer[pos=0 lim=46 cap=1024: 48 65 6C 6C 6F 20 53 65 72 76 65 72 2E 2E 2E 0D...]
[DEBUG] 2017-05-21 10:46:43 mina.tcp.handler.SimpleClientHandler =========messageSent...
[INFO ] 2017-05-21 10:46:43 org.apache.mina.filter.logging.LoggingFilter RECEIVED: HeapBuffer[pos=0 lim=46 cap=2048: 48 65 6C 6C 6F 20 43 6C 69 65 6E 74 2E 2E 2E 0D...]
[DEBUG] 2017-05-21 10:46:43 org.apache.mina.filter.codec.ProtocolCodecFilter Processing a MESSAGE_RECEIVED for session 1
[INFO ] 2017-05-21 10:46:43 mina.tcp.handler.SimpleClientHandler =========The message received from Server is:Hello Client...
[INFO ] 2017-05-21 10:46:43 mina.tcp.handler.SimpleClientHandler =========The message received from Server is:I'm Server...
[INFO ] 2017-05-21 10:46:43 org.apache.mina.filter.logging.LoggingFilter RECEIVED: HeapBuffer[pos=0 lim=46 cap=2048: 48 65 6C 6C 6F 20 43 6C 69 65 6E 74 2E 2E 2E 0D...]
[DEBUG] 2017-05-21 10:46:43 org.apache.mina.filter.codec.ProtocolCodecFilter Processing a MESSAGE_RECEIVED for session 1
[INFO ] 2017-05-21 10:46:43 mina.tcp.handler.SimpleClientHandler =========The message received from Server is:server test...Hello Client...
[INFO ] 2017-05-21 10:46:43 mina.tcp.handler.SimpleClientHandler =========The message received from Server is:I'm Server...
从上面的日志可以看出，LoggingFilter的输出在Handler日志前面，证明了，IoService发送的数据要经过IoFilter层，再由IoHandler处理。由于我们用的是TextLineCodecFactory（按行发送与接收数据），从日志输出来，client将多行数据一次发送，而server将发送过来的多行数据分行读取；client发送的为
Hello Server...\r\nI'm Client...\r\nclient test...
而server收到的为
1.Hello Server...
2.I'm Client...
这两行后面的client test...没有收到，证明TextLineCodecFactory是按行发送与接收数据，不到一行数据，不解析数据。
由于server接受了两次client发送过来的数据，并回复
Hello Client...\r\nI'm Server...\r\nserver test...
从client的输出来看，
第一次接收事件：
Hello Client...
I'm Server...
第二次接收事件：
server test...Hello Client...
I'm Server...
从上面可以看出，第一次没有解析完的数据留在缓冲区中，与下一次接收的数据合并处理。
整个过程：
client发生一次发送事件，server一次接收事件，多次调用handler处理行数据，并产生了多次发送事件，client相应的产生多次接收事件，并将上一次没有解析完的数据，与下一次接收的数据合并处理。
过滤器：
再来测试一下IoFilter，编写测试IoFilter
package mina.tcp.filter;
import org.apache.mina.core.filterchain.IoFilter;
import org.apache.mina.core.filterchain.IoFilterChain;
import org.apache.mina.core.session.IdleStatus;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.core.write.WriteRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* 测试过滤器
* @author donald
* 2017年5月19日
* 上午8:59:29
*/
public class TestFilter implements IoFilter {
private static final Logger log = LoggerFactory.getLogger(TestFilter.class);
@Override
public void onPreAdd(IoFilterChain parent, String name, NextFilter nextFilter) throws Exception {
log.debug("$$$$$$$$onPreAdd...");
}
@Override
public void onPostAdd(IoFilterChain parent, String name, NextFilter nextFilter) throws Exception {
log.debug("$$$$$$$$onPostAdd...");
}
@Override
public void init() throws Exception {
log.debug("$$$$$$$$init...");
}
@Override
public void filterWrite(NextFilter nextFilter, IoSession session, WriteRequest writeRequest) throws Exception {
log.debug("$$$$$$$$filterWrite...");
nextFilter.filterWrite(session, writeRequest);
}
@Override
public void sessionCreated(NextFilter nextFilter, IoSession session) throws Exception {
log.debug("$$$$$$$$sessionCreated...");
nextFilter.sessionCreated(session);
}
@Override
public void sessionIdle(NextFilter nextFilter, IoSession session, IdleStatus status) throws Exception {
log.debug("$$$$$$$$sessionIdle...");
nextFilter.sessionIdle(session, status);
}
@Override
public void sessionOpened(NextFilter nextFilter, IoSession session) throws Exception {
log.debug("$$$$$$$$sessionOpened...");
nextFilter.sessionOpened(session);
}
@Override
public void messageReceived(NextFilter nextFilter, IoSession session, Object message) throws Exception {
log.debug("$$$$$$$$messageReceived...");
nextFilter.messageReceived(session, message);
}
@Override
public void messageSent(NextFilter nextFilter, IoSession session, WriteRequest writeRequest) throws Exception {
log.debug("$$$$$$$$messageSent...");
nextFilter.messageSent(session, writeRequest);
}
@Override
public void exceptionCaught(NextFilter nextFilter, IoSession session, Throwable cause) throws Exception {
log.debug("$$$$$$$$exceptionCaught...");
nextFilter.exceptionCaught(session, cause);
}
@Override
public void onPostRemove(IoFilterChain parent, String name, NextFilter nextFilter) throws Exception {
log.debug("$$$$$$$$onPostRemove...");
}
@Override
public void onPreRemove(IoFilterChain parent, String name, NextFilter nextFilter) throws Exception {
log.debug("$$$$$$$$onPreRemove...");
}
@Override
public void inputClosed(NextFilter arg0, IoSession arg1) throws Exception {
log.debug("$$$$$$$$inputClosed...");
}
@Override
public void filterClose(NextFilter nextFilter, IoSession session) throws Exception {
log.debug("$$$$$$$$filterClose...");
nextFilter.filterClose(session);
}
@Override
public void sessionClosed(NextFilter nextFilter, IoSession session) throws Exception {
log.debug("$$$$$$$$sessionClosed...");
nextFilter.sessionClosed(session);
}
@Override
public void destroy() throws Exception {
log.debug("$$$$$$$$destroy...");
}
}
注意在filter*和session*及exceptionCaught方法调用时，要NextFilter相应方法，这一点和web的Filter#doFilter相似。
修改上一个实例中的Server端：
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.charset.Charset;
import org.apache.mina.core.filterchain.DefaultIoFilterChainBuilder;
import org.apache.mina.core.service.IoAcceptor;
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.LoggingFilter;
import org.apache.mina.filter.util.ReferenceCountingFilter;
import org.apache.mina.transport.socket.SocketSessionConfig;
import org.apache.mina.transport.socket.nio.NioSocketAcceptor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import mina.tcp.filter.TestFilter;
import mina.tcp.handler.SimpleServerHandler;
/**
* Simple Server With TestFilter
* @author donald
* 2017年5月19日
* 上午8:59:37
*/
public class SimpleServerWithTestFilter {
private static final Logger log = LoggerFactory.getLogger(SimpleServerWithTestFilter.class);
private static final String ip = "192.168.126.135";
private static final int port = 9122;
private static final int readBufferSize = 2048;
private static final int idleTime = 10;
private static final Charset charset = Charset.forName("UTF-8");
public static void main(String[] args) throws IOException {
IoAcceptor acceptor=new NioSocketAcceptor();
//配置socket会话
SocketSessionConfig socketSessionConfig = (SocketSessionConfig) acceptor.getSessionConfig();
socketSessionConfig.setReadBufferSize(readBufferSize);
socketSessionConfig.setIdleTime(IdleStatus.BOTH_IDLE,idleTime);
//配置过滤器
DefaultIoFilterChainBuilder defaultIoFilterChainBuilder = acceptor.getFilterChain();
LoggingFilter loggingFilter = new LoggingFilter();
defaultIoFilterChainBuilder.addLast("loggingFilter", loggingFilter);
TextLineCodecFactory textLineCodecFactory =
new TextLineCodecFactory(charset,LineDelimiter.WINDOWS.getValue(),
LineDelimiter.WINDOWS.getValue());
ProtocolCodecFilter protocolCodecFilter = new ProtocolCodecFilter(textLineCodecFactory);
defaultIoFilterChainBuilder.addLast("protocolCodecFilter",protocolCodecFilter);
TestFilter testFilter = new TestFilter();
ReferenceCountingFilter referenceCountingFilter = new ReferenceCountingFilter(testFilter);
defaultIoFilterChainBuilder.addLast("testFilter",referenceCountingFilter);
//配置NioSocketAcceptor处理器
SimpleServerHandler simpleServerHandler = new SimpleServerHandler();
acceptor.setHandler(simpleServerHandler);
InetSocketAddress inetSocketAddress = new InetSocketAddress(ip,port);
acceptor.bind(inetSocketAddress);
log.info("=========SimpleServer is start============");
}
}
启动SimpleServerWithTestFilter，server，及上例中的client，
SimpleServerWithTestFilter控制台输出：
[INFO ] 2017-05-21 00:51:54 mina.tcp.main.SimpleServerWithTestFilter =========SimpleServer is start============
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$init...
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$onPreAdd...
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$onPostAdd...
[INFO ] 2017-05-21 00:52:00 org.apache.mina.filter.logging.LoggingFilter CREATED
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$sessionCreated...
[DEBUG] 2017-05-21 00:52:00 mina.tcp.handler.SimpleServerHandler =========Session Created...
[INFO ] 2017-05-21 00:52:00 org.apache.mina.filter.logging.LoggingFilter OPENED
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$sessionOpened...
[DEBUG] 2017-05-21 00:52:00 mina.tcp.handler.SimpleServerHandler =========Session Opened...
[INFO ] 2017-05-21 00:52:00 org.apache.mina.filter.logging.LoggingFilter RECEIVED: HeapBuffer[pos=0 lim=46 cap=2048: 48 65 6C 6C 6F 20 53 65 72 76 65 72 2E 2E 2E 0D...]
[DEBUG] 2017-05-21 00:52:00 org.apache.mina.filter.codec.ProtocolCodecFilter Processing a MESSAGE_RECEIVED for session 1
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$messageReceived...
[INFO ] 2017-05-21 00:52:00 mina.tcp.handler.SimpleServerHandler =========The message received from Client is:Hello Server...
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$filterWrite...
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$messageReceived...
[INFO ] 2017-05-21 00:52:00 mina.tcp.handler.SimpleServerHandler =========The message received from Client is:I'm Client...
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$filterWrite...
[INFO ] 2017-05-21 00:52:00 org.apache.mina.filter.logging.LoggingFilter SENT: HeapBuffer[pos=0 lim=46 cap=1024: 48 65 6C 6C 6F 20 43 6C 69 65 6E 74 2E 2E 2E 0D...]
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$messageSent...
[DEBUG] 2017-05-21 00:52:00 mina.tcp.handler.SimpleServerHandler =========messageSent...
[INFO ] 2017-05-21 00:52:00 org.apache.mina.filter.logging.LoggingFilter SENT: HeapBuffer[pos=0 lim=46 cap=1024: 48 65 6C 6C 6F 20 43 6C 69 65 6E 74 2E 2E 2E 0D...]
[DEBUG] 2017-05-21 00:52:00 mina.tcp.filter.TestFilter $$$$$$$$messageSent...
[DEBUG] 2017-05-21 00:52:00 mina.tcp.handler.SimpleServerHandler =========messageSent...
从日志输出来看，init，onPreAdd，onPostAdd事件在会话创建时已经发生，这些方法主要用于初始化过滤器，添加过滤器到IoService
的过滤链时触发。会话事件顺序CREATED-》OPENED-》RECEIVED。从上面的日志输出可以看出整个过程的处理顺序为，
SimpleServerWithTestFilter-》LoggingFilter-》TestFilter-》ProtocolCodecFilter-》SimpleServerHandler，
过滤器的顺序默认为添加的顺序。在每次过滤器捕捉到接收数据事件，都将调用filterWrite方法。