zfdecoder.java

用mina框架编写的转发代理服务程序,含自动更新功能

package com.frontMachine.codec;

import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.UnmappableCharacterException;
import java.util.regex.Pattern;

import org.apache.log4j.Logger;
import org.apache.mina.common.ByteBuffer;
import org.apache.mina.common.IoSession;
import org.apache.mina.filter.codec.demux.MessageDecoderResult;
import org.apache.mina.util.CharsetUtil;

import com.frontMachine.setting.ServerSetting;
import com.frontMachine.util.ErrMsg;
import com.frontMachine.util.ExceptionLoger;

/**
 * @转发服务解码器
 * @author LRT
 * @version 1.0
 */
public class ZFDecoder extends AbstractDecoder
{
	public static Logger logger;
	static
	{
		logger = Logger.getLogger(ZFDecoder.class);
		String regular_string=ServerSetting.getInstance().getRegularExp();
		pattern= Pattern.compile(regular_string);
		String charset_name= ServerSetting.getInstance().getDeCharset();
		if(charset_name!=null)
		{
			charset=Charset.forName(charset_name);
		}
		else
		{
			System.out.println("get defaultcharset!!");
			charset=CharsetUtil.getDefaultCharset();
		}
	}
	
    public ZFDecoder()
    {
    }
    
    public  MessageDecoderResult decodable( IoSession session, ByteBuffer in )
    {
		byte[] b_msg=new byte[in.limit()];
		in.get(b_msg);
		String s_msg=new String(b_msg);
		matcher=pattern.matcher(s_msg);
		
		if(matcher.find())
		{
			return MessageDecoderResult.OK;
		}
		else
		{
			int eof = s_msg.indexOf("</AP>");
			if(eof >= 0) 
			{
				if( s_msg.substring(eof).length()>20) //</AP>加上通信MAC共21个字符,大于20证明数据包已经收全
				{
					logger.info(s_msg);
					return MessageDecoderResult.NOT_OK;	//返回NOT_OK 则handler出会捕捉到ProtocolDecoderException异常
				}
			}
			logger.info(s_msg+"数据包不全,继续接收...");
			return MessageDecoderResult.NEED_DATA;
		}
    }

    protected String decodeBody( IoSession session, ByteBuffer in )
    {
    	String result=null;
    	StringBuffer head=new StringBuffer();
    	CharsetDecoder decoder = charset.newDecoder();
    	for(int i=0;i<4;i++)	//单独处理数据包的前四个字节是长度信息(底位在前,高位在后),因为它对CharsetDecoder解码造成影响
    	{
    		byte b=in.get();
    		head.append((char)b);  
    	}
		try 					//解码数据包
		{
			result=in.getString(decoder);
		}
		catch(UnmappableCharacterException uce)
		{
			StringBuffer sb=new StringBuffer();
	    	while(in.hasRemaining())
	    	{
	    		byte b=in.get();
	    		sb.append((char)b);  
	    	}
			ExceptionLoger.ExLog(ErrMsg.ZF_UnmappableCharacterException);
			ExceptionLoger.ExLog(sb.toString());
			ExceptionLoger.ExLog(uce);
			return null;
		}
		catch(Exception e) {
			ExceptionLoger.ExLog(e);
			return null;
		}
    	return head.toString()+result.trim();
    }
    
   /* protected String decodeBody( IoSession session, ByteBuffer in )
    {
    	StringBuffer sb=new StringBuffer();
    	while(in.hasRemaining())
    	{
    		byte b=in.get();
    		sb.append((char)b);  
    	}
    	return sb.toString();
    }*/

}