我正在尝试使用CompletionHandler而不是Futures在vert.x辅助版本中的AsynchronousSocketChannel上实现单个请求/响应。从vert.x文档中:
“工作台永远不会由多个线程同时执行。”
所以这是我的代码(不确定我是否正确处理了套接字的100%-请发表评论):
// ommitted: asynchronousSocketChannel.open, connect ...
eventBus.registerHandler(address, new Handler<Message<JsonObject>>() {
@Override
public void handle(final Message<JsonObject> event) {
final ByteBuffer receivingBuffer = ByteBuffer.allocateDirect(2048);
final ByteBuffer sendingBuffer = ByteBuffer.wrap("Foo".getBytes());
asynchronousSocketChannel.write(sendingBuffer, 0L, new CompletionHandler<Integer, Long>() {
public void completed(final Integer result, final Long attachment) {
if (sendingBuffer.hasRemaining()) {
long newFilePosition = attachment + result;
asynchronousSocketChannel.write(sendingBuffer, newFilePosition, this);
}
asynchronousSocketChannel.read(receivingBuffer, 0L, new CompletionHandler<Integer, Long>() {
CharBuffer charBuffer = null;
final Charset charset = Charset.defaultCharset();
final CharsetDecoder decoder = charset.newDecoder();
public void completed(final Integer result, final Long attachment) {
if (result > 0) {
long p = attachment + result;
asynchronousSocketChannel.read(receivingBuffer, p, this);
}
receivingBuffer.flip();
try {
charBuffer = decoder.decode(receivingBuffer);
event.reply(charBuffer.toString()); // pseudo code
} catch (CharacterCodingException e) { }
}
public void failed(final Throwable exc, final Long attachment) { }
});
}
public void failed(final Throwable exc, final Long attachment) { }
});
}
});
在负载测试期间,我遇到了很多ReadPendingException和WritePendingException的问题,如果handle方法中实际上一次只有一个线程,这似乎有些奇怪。如果一次只有1个线程与AsynchronousSocketChannel一起工作,怎么可能没有完全完成读取或写入操作?
最佳答案
来自AsynchronousSocketChannel的处理程序在其自己的AsynchronousChannelGroup上执行,该组是ExecutorService的派生类。除非您做出特殊的努力,否则处理程序将与启动I / O操作的代码并行执行。
要在一个Verticle中执行I / O完成处理程序,您必须在该Verticle中创建并注册一个处理程序,该处理程序现在执行AsynchronousSocketChannel的处理程序。
AsynchronousSocketChannel的处理程序应仅将其参数(结果和附件)打包在消息中,然后将该消息发送到事件总线。