mina,TextLineDecoder

最新推荐文章于 2021-08-10 23:30:01 发布

原创最新推荐文章于 2021-08-10 23:30:01 发布 · 5.2k 阅读

1 ·

CC 4.0 BY-SA版权

文章标签：

#mina #buffer #primitive #structure #exception #session

Web 专栏收录该内容

40 篇文章

订阅专栏

本文介绍了一个自定义的Mina TextLineDecoder子类，通过在接收缓冲区末尾追加换行符来避免客户端因未接收到结束符而无限等待的问题，并解释了Buffer的工作原理。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

使用mina的TextLineDecoder，可以指定接收数据的结束符号，但如果没有指定结束符，就默认会去匹配'/n'或者'/r'结束符

如果从服务端返回的数据没有包含这些结束符，客户端就会等待。

为了不让客户端等待下去，可以增加一个TextLineDecoder子类，如下：

public class ClientTextLineDecoder extends TextLineDecoder {

    @Override
    public void decode(IoSession session, IoBuffer in, ProtocolDecoderOutput out)
            throws Exception {

/*--------在当前buffer后面追加一个'/n' -------*/

        in.setAutoExpand(true);//设置自动扩展
        in.position(in.limit());
        in.put((byte)'/n');
        in.position(0);



        super.decode(session, in, out);
    }



}

我们只要在调用父类的decode方法之前在buffer后面追加一个'/n'结束符，就可以解决问题。

下面是buffer相关的知识：

Buffer foundations

The abstract Buffer class forms the foundation of the java.nio package's buffer support. Buffer works like an in-memory RandomAccessFile for reading and writing primitive data types. Like a RandomAccessFile , with Buffer the next operation you perform (read/write) happens at your position. Performing either operation changes that position, so doing a read after a write doesn't read what was just written, but what is after what was just written. Buffer offers four indicators for access to the linear structure (from highest value to lowest):

capacity() : Indicates the buffer's size
limit() : Tells you how many bytes you've stuffed into the buffer so far, or lets you change that limit with :limit(int newLimit) :
position() : Tells you the current location to perform the next read/write operation
mark() : Lets you remember a position for later resetting with reset()