Apache Mina使用手记（三）
在上一篇中，通过一个简单的例子，得以管中窥豹，了解了Mina的基本编写方法。在MinaTimeServer演示程序中，我们添加了两个过滤器，一个是日志过滤器LoggingFilter，一个是文本编解码过滤器。前者实现日志信息的自动处理，后者实现对按行读写的文本数据的编码和解码。
其中LoggingFilter默认的是slf4j，它是一个日志Facade，实际并不实现真正的日志处理功能，它在程序运行时自动判断classpath中加载的日志组件，比如：log4j/Logback/JUL等，确定之后调用真正的日志组件实现真正的日志处理操作。这一点对于组件式的程序，很明显是非常灵活的，因为你并不知道用户的实际环境中使用的是log4j还是JUL，或者是Logback等，但是为了实现自动识别，slf4j默认了log配置文件的加载位置，让我觉得十分不便。
我自己的所有系统中，都使用是log4j（他的替代产品Logback已经出来了，据说性能更强），我一般喜欢把所有配置文件包括log4j.properties都放在conf目录下，以便管理。因此，对于slf4j中需要把log4j.properties放在src文件夹下非常不习惯，对于以后管理也容易引起混乱。所以，我希望能直接实现自己的log4j过滤器，按以前的方式使用。我们观察一下LoggingFilter过滤器的源代码，如下所示：
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[*]public class LoggingFilter extends IoFilterAdapter{...}
LoggingFilter继承自IoFilterAdapter，它是java模型中的适配器模式，是对接口IoFilter的包装。我们可以模仿LoggingFilter，实现自己的Log4jFilter类：
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[*]import org.apache.log4j.Level;
[*]import org.apache.log4j.Logger;
[*]import org.apache.mina.core.filterchain.IoFilterAdapter;
[*]import org.apache.mina.core.session.IdleStatus;
[*]import org.apache.mina.core.session.IoSession;
[*]import org.apache.mina.core.write.WriteRequest;
[*]import org.apache.mina.filter.logging.LogLevel;
[*]import org.slf4j.helpers.MessageFormatter;
[*]public class Log4jFilter extends IoFilterAdapter {
[*] /** The logger name */
[*] private final String name;
[*]
[*] /** The logger */
[*] private final Logger logger;
[*]
[*] /** The log level for the exceptionCaught event. Default to WARN. */
[*] private LogLevel exceptionCaughtLevel = LogLevel.WARN;
[*]
[*] /** The log level for the messageSent event. Default to INFO. */
[*] private LogLevel messageSentLevel = LogLevel.INFO;
[*]
[*] /** The log level for the messageReceived event. Default to INFO. */
[*] private LogLevel messageReceivedLevel = LogLevel.INFO;
[*]
[*] /** The log level for the sessionCreated event. Default to INFO. */
[*] private LogLevel sessionCreatedLevel = LogLevel.INFO;
[*]
[*] /** The log level for the sessionOpened event. Default to INFO. */
[*] private LogLevel sessionOpenedLevel = LogLevel.INFO;
[*]
[*] /** The log level for the sessionIdle event. Default to INFO. */
[*] private LogLevel sessionIdleLevel = LogLevel.INFO;
[*]
[*] /** The log level for the sessionClosed event. Default to INFO. */
[*] private LogLevel sessionClosedLevel = LogLevel.INFO;
[*]
[*] /**
[*] * Default Constructor.
[*] */
[*] public Log4jFilter(Logger logger) {
[*] this.logger=logger;
[*] this.name=logger.getName();
[*] }
[*]
[*]
[*]
[*] /**
[*] * @return The logger's name
[*] */
[*] public String getName() {
[*] return name;
[*] }
[*]
[*] /**
[*] * Log if the logger and the current event log level are compatible. We log
[*] * a message and an exception.
[*] *
[*] * @param eventLevel the event log level as requested by the user
[*] * @param message the message to log
[*] * @param cause the exception cause to log
[*] */
[*] private void log(LogLevel eventLevel, String message, Throwable cause) {
[*] if (eventLevel == LogLevel.TRACE) {
[*] logger.trace(message, cause);
[*] } else if (eventLevel.getLevel() > LogLevel.INFO.getLevel()) {
[*] logger.info(message, cause);
[*] } else if (eventLevel.getLevel() > LogLevel.WARN.getLevel()) {
[*] logger.warn(message, cause);
[*] } else if (eventLevel.getLevel() > LogLevel.ERROR.getLevel()) {
[*] logger.error(message, cause);
[*] }
[*] }
[*] /**
[*] * Log if the logger and the current event log level are compatible. We log
[*] * a formated message and its parameters.
[*] *
[*] * @param eventLevel the event log level as requested by the user
[*] * @param message the formated message to log
[*] * @param param the parameter injected into the message
[*] */
[*] private void log(LogLevel eventLevel, String message, Object param) {
[*] String msgStr = MessageFormatter.format(message, param);
[*] if (eventLevel == LogLevel.TRACE) {
[*] logger.log(name, Level.TRACE, msgStr, null);
[*]
[*] } else if (eventLevel.getLevel() > LogLevel.INFO.getLevel()) {
[*] logger.log(name, Level.INFO, msgStr, null);
[*] } else if (eventLevel.getLevel() > LogLevel.WARN.getLevel()) {
[*] logger.log(name, Level.WARN, msgStr, null);
[*] } else if (eventLevel.getLevel() > LogLevel.ERROR.getLevel()) {
[*] logger.log(name, Level.ERROR, msgStr, null);
[*] }
[*] }
[*] /**
[*] * Log if the logger and the current event log level are compatible. We log
[*] * a simple message.
[*] *
[*] * @param eventLevel the event log level as requested by the user
[*] * @param message the message to log
[*] */
[*] private void log(LogLevel eventLevel, String message) {
[*] if (eventLevel == LogLevel.TRACE) {
[*] logger.trace(message);
[*] } else if (eventLevel.getLevel() > LogLevel.INFO.getLevel()) {
[*] logger.info(message);
[*] } else if (eventLevel.getLevel() > LogLevel.WARN.getLevel()) {
[*] logger.warn(message);
[*] } else if (eventLevel.getLevel() > LogLevel.ERROR.getLevel()) {
[*] logger.error(message);
[*] }
[*] }
[*] @Override
[*] public void exceptionCaught(NextFilter nextFilter, IoSession session,
[*] Throwable cause) throws Exception {
[*] log(exceptionCaughtLevel, "EXCEPTION :", cause);
[*] nextFilter.exceptionCaught(session, cause);
[*] }
[*] @Override
[*] public void messageReceived(NextFilter nextFilter, IoSession session,
[*] Object message) throws Exception {
[*] log(messageReceivedLevel, "RECEIVED: {}", message );
[*] nextFilter.messageReceived(session, message);
[*] }
[*] @Override
[*] public void messageSent(NextFilter nextFilter, IoSession session,
[*] WriteRequest writeRequest) throws Exception {
[*] log(messageSentLevel, "SENT: {}", writeRequest.getMessage() );
[*] nextFilter.messageSent(session, writeRequest);
[*] }
[*] @Override
[*] public void sessionCreated(NextFilter nextFilter, IoSession session)
[*] throws Exception {
[*] log(sessionCreatedLevel, "CREATED");
[*] nextFilter.sessionCreated(session);
[*] }
[*] @Override
[*] public void sessionOpened(NextFilter nextFilter, IoSession session)
[*] throws Exception {
[*] log(sessionOpenedLevel, "OPENED");
[*] nextFilter.sessionOpened(session);
[*] }
[*] @Override
[*] public void sessionIdle(NextFilter nextFilter, IoSession session,
[*] IdleStatus status) throws Exception {
[*] log(sessionIdleLevel, "IDLE");
[*] nextFilter.sessionIdle(session, status);
[*] }
[*] @Override
[*] public void sessionClosed(NextFilter nextFilter, IoSession session) throws Exception {
[*] log(sessionClosedLevel, "CLOSED");
[*] nextFilter.sessionClosed(session);
[*] }
[*]
[*] /**
[*] * Set the LogLevel for the ExceptionCaught event.
[*] *
[*] * @param level The LogLevel to set
[*] */
[*] public void setExceptionCaughtLoglevel(LogLevel level) {
[*] exceptionCaughtLevel = level;
[*] }
[*]
[*] /**
[*] * Get the LogLevel for the ExceptionCaught event.
[*] *
[*] * @return The LogLevel for the ExceptionCaught eventType
[*] */
[*] public LogLevel getExceptionCaughtLoglevel() {
[*] return exceptionCaughtLevel;
[*] }
[*]
[*] /**
[*] * Set the LogLevel for the MessageReceived event.
[*] *
[*] * @param level The LogLevel to set
[*] */
[*] public void setMessageReceivedLoglevel(LogLevel level) {
[*] messageReceivedLevel = level;
[*] }
[*]
[*] /**
[*] * Get the LogLevel for the MessageReceived event.
[*] *
[*] * @return The LogLevel for the MessageReceived eventType
[*] */
[*] public LogLevel getMessageReceivedLoglevel() {
[*] return messageReceivedLevel;
[*] }
[*]
[*] /**
[*] * Set the LogLevel for the MessageSent event.
[*] *
[*] * @param level The LogLevel to set
[*] */
[*] public void setMessageSentLoglevel(LogLevel level) {
[*] messageSentLevel = level;
[*] }
[*]
[*] /**
[*] * Get the LogLevel for the MessageSent event.
[*] *
[*] * @return The LogLevel for the MessageSent eventType
[*] */
[*] public LogLevel getMessageSentLoglevel() {
[*] return messageSentLevel;
[*] }
[*]
[*] /**
[*] * Set the LogLevel for the SessionCreated event.
[*] *
[*] * @param level The LogLevel to set
[*] */
[*] public void setSessionCreatedLoglevel(LogLevel level) {
[*] sessionCreatedLevel = level;
[*] }
[*]
[*] /**
[*] * Get the LogLevel for the SessionCreated event.
[*] *
[*] * @return The LogLevel for the SessionCreated eventType
[*] */
[*] public LogLevel getSessionCreatedLoglevel() {
[*] return sessionCreatedLevel;
[*] }
[*]
[*] /**
[*] * Set the LogLevel for the SessionOpened event.
[*] *
[*] * @param level The LogLevel to set
[*] */
[*] public void setSessionOpenedLoglevel(LogLevel level) {
[*] sessionOpenedLevel = level;
[*] }
[*]
[*] /**
[*] * Get the LogLevel for the SessionOpened event.
[*] *
[*] * @return The LogLevel for the SessionOpened eventType
[*] */
[*] public LogLevel getSessionOpenedLoglevel() {
[*] return sessionOpenedLevel;
[*] }
[*]
[*] /**
[*] * Set the LogLevel for the SessionIdle event.
[*] *
[*] * @param level The LogLevel to set
[*] */
[*] public void setSessionIdleLoglevel(LogLevel level) {
[*] sessionIdleLevel = level;
[*] }
[*]
[*] /**
[*] * Get the LogLevel for the SessionIdle event.
[*] *
[*] * @return The LogLevel for the SessionIdle eventType
[*] */
[*] public LogLevel getSessionIdleLoglevel() {
[*] return sessionIdleLevel;
[*] }
[*]
[*] /**
[*] * Set the LogLevel for the SessionClosed event.
[*] *
[*] * @param level The LogLevel to set
[*] */
[*] public void setSessionClosedLoglevel(LogLevel level) {
[*] sessionClosedLevel = level;
[*] }
[*] /**
[*] * Get the LogLevel for the SessionClosed event.
[*] *
[*] * @return The LogLevel for the SessionClosed eventType
[*] */
[*] public LogLevel getSessionClosedLoglevel() {
[*] return sessionClosedLevel;
[*] }
[*]}
其实代码很类似，在MinaTimeServer中使用Log4jFilter使使看：
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[*]package com.gftech.mytool.mina;
[*]import java.io.IOException;
[*]import java.net.InetSocketAddress;
[*]import java.nio.charset.Charset;
[*]import java.util.Date;
[*]import org.apache.log4j.Logger;
[*]import org.apache.log4j.PropertyConfigurator;
[*]import org.apache.mina.core.service.IoAcceptor;
[*]import org.apache.mina.core.service.IoHandlerAdapter;
[*]import org.apache.mina.core.session.IdleStatus;
[*]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.NioSocketAcceptor;
[*]public class MinaTimeServer {
[*] private static final int PORT = 2500;
[*] // static Logger logger = LoggerFactory.getLogger(MinaTimeServer.class);
[*] static Logger logger = Logger.getLogger(MinaTimeServer.class);
[*] public static void main(String[] args) throws IOException {
[*] PropertyConfigurator.configure("conf//log4j.properties");
[*] IoAcceptor acceptor = new NioSocketAcceptor();
[*] // LoggingFilter lf = new LoggingFilter("testLog");
[*] Log4jFilter lf = new Log4jFilter(logger);
[*] acceptor.getFilterChain().addLast("logger", lf);
[*] acceptor.getFilterChain().addLast("codec", new ProtocolCodecFilter(new TextLineCodecFactory(Charset.forName("GBK"))));
[*] acceptor.setHandler(new TimeServerHandler());
[*] acceptor.getSessionConfig().setReadBufferSize(10);
[*] acceptor.getSessionConfig().setIdleTime(IdleStatus.BOTH_IDLE, 10);
[*] acceptor.bind(new InetSocketAddress(PORT));
[*] System.out.println("start server ...");
[*] }
[*]}
[*]class TimeServerHandler extends IoHandlerAdapter {
[*] // static Logger logger = LoggerFactory.getLogger(TimeServerHandler.class);
[*] static Logger logger = Logger.getLogger(TimeServerHandler.class);
[*] @Override
[*] public void exceptionCaught(IoSession session, Throwable cause) throws Exception {
[*] cause.printStackTrace();
[*] }
[*] @Override
[*] public void messageReceived(IoSession session, Object message) throws Exception {
[*] String str = message.toString();
[*] if (str.trim().equalsIgnoreCase("quit")) {
[*] session.close(true);
[*] return;
[*] }
[*] logger.debug("Rec:" + str);
[*] Date date = new Date();
[*] session.write(date.toString());
[*] logger.debug("Message written...");
[*] }
[*] @Override
[*] public void sessionIdle(IoSession session, IdleStatus status) throws Exception {
[*] logger.debug("IDLE " + session.getIdleCount(status));
[*] }
[*]}
把配置文件按照自己的习惯放到conf目录下，就可以正常使用了。
需要注意的是，增加了自己的Log4jFilter之后，只能在您自己的代码中实现logger.debug()之类的调用时产生的日志记录才是正常的，即按配置文件中的要求老老实实进行日志记录。对于Mina代码中用到的logger调用，因为还是用的默认的slf4j，找不到src目录下的log4j.properties，所以产生的日志将无法正确显示和记录。除非您自己的将mina源代码中的logger全部改成log4j的logger，这是个小小的遗憾，鱼和熊掌不能兼得呀。
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