serialdecoder.java

银行项目为后台ｓｏｃｋｅｔ通信写的程序

/****************************************************************************
 * Package		: com.ecSolutions.ecAppServer.server.decoder
 * File			: SerialDecoder.java
 * Create Date  : 2007-7-20
 * Author		: Steven Chen
 * 
 * Copyright(C) 2006 ecSolutions(shanghai) Co.,Limited.All Rights Reserved.
 *			
 ***************************************************************************/
package com.ecSolutions.ecAppServer.server.decoder;

import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectStreamConstants;

import com.ecSolutions.ecAppServer.server.Buffer;
import com.ecSolutions.ecAppServer.server.Packet;
import com.ecSolutions.ecAppServer.server.PacketDecoder;
import com.ecSolutions.ecAppServer.server.Session;

/**
 * Decode <code>Packet</code> to serial object.
 * 
 * @author Steven Chen
 * @version $Id: SerialDecoder.java,v 1.3 2007/07/26 03:15:53 stevenchen Exp $
 */
public class SerialDecoder implements PacketDecoder {

    public Object decode(Session session, Packet packet) throws Exception {
        final Buffer buffer = packet.getContent();
        if (buffer.remaining() < 4)
            return null;

        if (buffer.getShort() == ObjectStreamConstants.STREAM_MAGIC
                && buffer.getShort() == ObjectStreamConstants.STREAM_VERSION) {
            buffer.skip(-4);

            ObjectInputStream is = null;
            try {
                is = new ObjectInputStream(new InputStream() {

                    public int read() {
                        return buffer.hasRemaining() ? buffer.get() : -1;
                    }

                    public int read(byte[] bytes, int off, int len) {
                        if (buffer.hasRemaining()) {
                            len = Math.min(len, buffer.remaining());
                            buffer.get(bytes, off, len);
                            return len;
                        }
                        return -1;
                    }

                });
                return is.readObject();
            } catch (EOFException e) {
            } finally {
                if (is != null) {
                    try {
                        is.close();
                    } catch (IOException e) {
                    }
                }
            }
        }
        return null;
    }
}