mina消息过长

 * Decode a line using the default delimiter on the current system
 */
private void (Context ctx, IoSession session, IoBuffer in, ProtocolDecoderOutput out)
        throws CharacterCodingException, ProtocolDecoderException {
    int matchCount = ctx.getMatchCount();
    // Try to find a match
    int oldPos = in.position();
    int oldLimit = in.limit();
    while (in.hasRemaining()) {
        byte b = in.get();
        boolean matched = false;
        switch (b) {
        case 'r':
            // Might be Mac, but we don't auto-detect Mac EOL
            // to avoid confusion.
            matchCount++;
            break;
        case 'n':
            // UNIX
            matchCount++;
            matched = true;
            break;
        default:
            matchCount = 0;
        }
        if (matched) {
            // Found a match.
            int pos = in.position();
            in.limit(pos);
            in.position(oldPos);
            ctx.append(in);
            in.limit(oldLimit);
            in.position(pos);
            if (ctx.getOverflowPosition() == 0) {
                IoBuffer buf = ctx.getBuffer();
                buf.flip();
                buf.limit(buf.limit() - matchCount);
                try {
                    byte[] data = new byte[buf.limit()];
                    buf.get(data);
                    CharsetDecoder decoder = ctx.getDecoder();
                    CharBuffer buffer = decoder.decode(ByteBuffer.wrap(data));
                    String str = buffer.toString();
                    writeText(session, str, out);
                } finally {
                    buf.clear();
                }
            } else {
                int overflowPosition = ctx.getOverflowPosition();
                ctx.reset();
                throw new RecoverableProtocolDecoderException("Line is too long: " + overflowPosition);
            }
            oldPos = pos;
            matchCount = 0;
        }
    }
    // Put remainder to buf.
    in.position(oldPos);
    ctx.append(in);
    ctx.setMatchCount(matchCount);
}

TextLineCodecFactory lineCodec=new TextLineCodecFactory();
lineCodec.setDecoderMaxLineLength(1024*1024); //1M
filterChain.addLast("codec", new ProtocolCodecFilter(lineCodec));

 * Sets the allowed maximum size of the line to be decoded.
 * If the size of the line to be decoded exceeds this value, the
 * decoder will throw a {@link BufferDataException}.  The default
 * value is <tt>1024</tt> (1KB).
 * <p>
 * This method does the same job with {@link TextLineDecoder#setMaxLineLength(int)}.
 * 
 * @param maxLineLength the maximum decoded line length
 */
public void setDecoderMaxLineLength(int maxLineLength) {
    decoder.setMaxLineLength(maxLineLength);
}

 * Provides {@link ProtocolEncoder} and {@link ProtocolDecoder} which translates
 * binary or protocol specific data into message object and vice versa.
 * <p>
 * Please refer to
 * <a href="../../../../../xref-examples/org/apache/mina/examples/reverser/ReverseProtocolProvider.html"><code>ReverserProtocolProvider</code></a>
 * example.
 *
 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
 */
public interface ProtocolCodecFactory {
    
     * Returns a new (or reusable) instance of {@link ProtocolEncoder} which
     * encodes message objects into binary or protocol-specific data.
     * 
     * @param session The current session
     * @return The encoder instance
     * @throws Exception If an error occurred while retrieving the encoder
     */
    ProtocolEncoder getEncoder(IoSession session) throws Exception;
    
     * Returns a new (or reusable) instance of {@link ProtocolDecoder} which
     * decodes binary or protocol-specific data into message objects.
     * 
     * @param session The current session
     * @return The decoder instance
     * @throws Exception If an error occurred while retrieving the decoder
     */
    ProtocolDecoder getDecoder(IoSession session) throws Exception;
}