mina接收数据不全（2）

由apache mina建立的socket不管是采用TCP或是UDP，在Filter不添加codec选项的情况下，由IoHandlerAdapter派生的处理 handler 类中public void messageReceived(IoSession session, Object message){}函数里的message对象是IoBuffer的实例，如下：
@Override
    public void messageReceived(IoSession session, Object message)
            throws Exception {

        if (! (message instanceof IoBuffer)) {
              return;
           }

        IoBuffer rb = (IoBuffer) message;
        callback.messageReceived(java.nio.ByteBuffer.wrap(rb.array(), 0, rb.buf().limit()));
    }

另外提醒：
1、如果你使用mina建立一个socket添加了如下：
IoFilter CODEC_FILTER = new ProtocolCodecFilter(
                new TextLineCodecFactory());
connector(acceptor).getFilterChain().addLast("codec", CODEC_FILTER);
如果发送数据的socket不是同样的设置或者不是利用mina建立的socket则发送数据的时候需要在数据末尾添加‘\n’，以表示字符串结束。

2、 由于我们使用mina socket读取数据时通常都是采用其通知接收的方式，所以我们必须留心接收数据的完整性，如果你使用mina socket接收数据不完整，在确认自己接收处理代码无误后，请检查一下org\apache\mina\core\polling \AbstractPollingIoProcessor.java中的代码的如下红色部分：

private void read(T session) {
        IoSessionConfig config = session.getConfig();
        IoBuffer buf = IoBuffer.allocate(config.getReadBufferSize());

        final boolean hasFragmentation =
            session.getTransportMetadata().hasFragmentation();

        try {
            int readBytes = 0;
            int ret;

            try {
                if (hasFragmentation) {
                    while ((ret = read(session, buf)) > 0) {
                        readBytes += ret;
                        if (!buf.hasRemaining()) {
                            break;
                        }
                    }
                } else {
                    ret = read(session, buf);
                    if (ret > 0) {
                        readBytes = ret;
                    }
                }
            } finally {
                buf.flip();
            }

            if (readBytes > 0) {
                IoFilterChain filterChain = session.getFilterChain();
                filterChain.fireMessageReceived(buf);
                buf = null;

                if (hasFragmentation) {
                    if (readBytes << 1 < config.getReadBufferSize()) {
                        session.decreaseReadBufferSize();
                    } else if (readBytes == config.getReadBufferSize()) {
                        session.increaseReadBufferSize();
                    }
                }
            }
            if (ret < 0) {
                scheduleRemove(session);
            }
        } catch (Throwable e) {
            if (e instanceof IOException) {
                scheduleRemove(session);
            }
            IoFilterChain filterChain = session.getFilterChain();
            filterChain.fireExceptionCaught(e);
        }
    }