我正在尝试将我的错误处理泛化为HTTP请求，并始终使用实际错误HTTP代码和相关消息进行响应。
这是我的问题：在我的Handler中扩展了SimpleChannelUpstreamHandler，当在堆栈中的任何地方抛出异常时会触发exceptionCaught。非常好。不好的一点是，当我尝试用适当的HTTP代码和响应写出对客户端的响应时，写入会导致异常，然后程序进入无限循环，一遍又一遍地调用exceptionCaught。
这必须是一项常见的任务。我怎么能正确地做到这一点？
@Override
public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent event)
throws Exception {
try{
logger.error("Error in handling call: ", event.getCause());
HttpResponse httpResponse = buildHttpResponseObject(UNAUTHORIZED, new StringBuilder("Test"), false, null);
// Write the response.
// for some reason calling this next line causes an infinite loop of exceptionCaught, even with the
// catch below. No idea why. Still investigating. In the meantime, we don't have custom error code responses.
ChannelFuture future = event.getChannel().write(httpResponse);
// Close the connection after the write operation is done, even if it's a keep-alive.
future.addListener(ChannelFutureListener.CLOSE);
}
catch(Exception t){
logger.error("Unable to customize error response. ", t);
event.getChannel().close();
}
}
以下是例外情况：
38161 [New I/O server worker #1-1] ERROR nettytests.http.snoop.HttpSnoopServerHandler - Error in handling call:
javax.net.ssl.SSLHandshakeException: null cert chain
at sun.security.ssl.Handshaker.checkThrown(Handshaker.java:1364)
at sun.security.ssl.SSLEngineImpl.checkTaskThrown(SSLEngineImpl.java:513)
at sun.security.ssl.SSLEngineImpl.readNetRecord(SSLEngineImpl.java:790)
at sun.security.ssl.SSLEngineImpl.unwrap(SSLEngineImpl.java:758)
at javax.net.ssl.SSLEngine.unwrap(SSLEngine.java:624)
at org.jboss.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:931)
at org.jboss.netty.handler.ssl.SslHandler.decode(SslHandler.java:649)
at org.jboss.netty.handler.codec.frame.FrameDecoder.callDecode(FrameDecoder.java:288)
at org.jboss.netty.handler.codec.frame.FrameDecoder.messageReceived(FrameDecoder.java:207)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:343)
at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:274)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:194)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
Caused by: javax.net.ssl.SSLHandshakeException: null cert chain
at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1639)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:278)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:266)
at sun.security.ssl.ServerHandshaker.clientCertificate(ServerHandshaker.java:1627)
at sun.security.ssl.ServerHandshaker.processMessage(ServerHandshaker.java:176)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:868)
at sun.security.ssl.Handshaker$1.run(Handshaker.java:808)
at sun.security.ssl.Handshaker$1.run(Handshaker.java:806)
at java.security.AccessController.doPrivileged(Native Method)
at sun.security.ssl.Handshaker$DelegatedTask.run(Handshaker.java:1301)
at org.jboss.netty.handler.ssl.SslHandler$3.run(SslHandler.java:1060)
at org.jboss.netty.handler.ssl.ImmediateExecutor.execute(ImmediateExecutor.java:31)
at org.jboss.netty.handler.ssl.SslHandler.runDelegatedTasks(SslHandler.java:1057)
at org.jboss.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:947)
... 11 more
38177 [New I/O server worker #1-1] ERROR nettytests.http.snoop.HttpSnoopServerHandler - Error in handling call:
java.lang.IllegalStateException: cannot send more responses than requests
at org.jboss.netty.handler.codec.http.HttpContentEncoder.writeRequested(HttpContentEncoder.java:104)
at org.jboss.netty.channel.Channels.write(Channels.java:605)
at org.jboss.netty.channel.Channels.write(Channels.java:572)
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:245)
at nettytests.http.snoop.HttpSnoopServerHandler.exceptionCaught(HttpSnoopServerHandler.java:201)
at nettytests.logger.RequestAuditLogger.handleUpstream(RequestAuditLogger.java:32)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:456)
at org.jboss.netty.handler.ssl.SslHandler.exceptionCaught(SslHandler.java:554)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:426)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:47)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:343)
at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:274)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:194)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
38177 [New I/O server worker #1-1] ERROR nettytests.http.snoop.HttpSnoopServerHandler - Error in handling call:
java.lang.IllegalStateException: cannot send more responses than requests
at org.jboss.netty.handler.codec.http.HttpContentEncoder.writeRequested(HttpContentEncoder.java:104)
at org.jboss.netty.channel.Channels.write(Channels.java:605)
at org.jboss.netty.channel.Channels.write(Channels.java:572)
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:245)
at nettytests.http.snoop.HttpSnoopServerHandler.exceptionCaught(HttpSnoopServerHandler.java:201)
at nettytests.logger.RequestAuditLogger.handleUpstream(RequestAuditLogger.java:32)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:456)
at org.jboss.netty.handler.ssl.SslHandler.exceptionCaught(SslHandler.java:554)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:426)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:47)
at org.jboss.netty.channel.Channels.write(Channels.java:605)
at org.jboss.netty.channel.Channels.write(Channels.java:572)
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:245)
at nettytests.http.snoop.HttpSnoopServerHandler.exceptionCaught(HttpSnoopServerHandler.java:201)
at nettytests.logger.RequestAuditLogger.handleUpstream(RequestAuditLogger.java:32)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:456)
at org.jboss.netty.handler.ssl.SslHandler.exceptionCaught(SslHandler.java:554)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:426)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:47)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:343)
at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:274)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:194)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
38224 [New I/O server worker #1-1] ERROR nettytests.http.snoop.HttpSnoopServerHandler - Error in handling call:
java.lang.IllegalStateException: cannot send more responses than requests
at org.jboss.netty.handler.codec.http.HttpContentEncoder.writeRequested(HttpContentEncoder.java:104)
at org.jboss.netty.channel.Channels.write(Channels.java:605)
at org.jboss.netty.channel.Channels.write(Channels.java:572)
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:245)
at nettytests.http.snoop.HttpSnoopServerHandler.exceptionCaught(HttpSnoopServerHandler.java:201)
at nettytests.logger.RequestAuditLogger.handleUpstream(RequestAuditLogger.java:32)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:456)
at org.jboss.netty.handler.ssl.SslHandler.exceptionCaught(SslHandler.java:554)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:426)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:47)
at org.jboss.netty.channel.Channels.write(Channels.java:605)
at org.jboss.netty.channel.Channels.write(Channels.java:572)
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:245)
at nettytests.http.snoop.HttpSnoopServerHandler.exceptionCaught(HttpSnoopServerHandler.java:201)
at nettytests.logger.RequestAuditLogger.handleUpstream(RequestAuditLogger.java:32)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:456)
at org.jboss.netty.handler.ssl.SslHandler.exceptionCaught(SslHandler.java:554)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:426)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:47)
at org.jboss.netty.channel.Channels.write(Channels.java:605)
at org.jboss.netty.channel.Channels.write(Channels.java:572)
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:245)
at nettytests.http.snoop.HttpSnoopServerHandler.exceptionCaught(HttpSnoopServerHandler.java:201)
at nettytests.logger.RequestAuditLogger.handleUpstream(RequestAuditLogger.java:32)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:456)
at org.jboss.netty.handler.ssl.SslHandler.exceptionCaught(SslHandler.java:554)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:426)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:47)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:343)
at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:274)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:194)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
38255 [New I/O server worker #1-1] ERROR nettytests.http.snoop.HttpSnoopServerHandler - Error in handling call:
java.lang.IllegalStateException: cannot send more responses than requests
at org.jboss.netty.handler.codec.http.HttpContentEncoder.writeRequested(HttpContentEncoder.java:104)
at org.jboss.netty.channel.Channels.write(Channels.java:605)
at org.jboss.netty.channel.Channels.write(Channels.java:572)
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:245)
at nettytests.http.snoop.HttpSnoopServerHandler.exceptionCaught(HttpSnoopServerHandler.java:201)
at nettytests.logger.RequestAuditLogger.handleUpstream(RequestAuditLogger.java:32)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:456)
at org.jboss.netty.handler.ssl.SslHandler.exceptionCaught(SslHandler.java:554)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:426)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:47)
at org.jboss.netty.channel.Channels.write(Channels.java:605)
at org.jboss.netty.channel.Channels.write(Channels.java:572)
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:245)
at nettytests.http.snoop.HttpSnoopServerHandler.exceptionCaught(HttpSnoopServerHandler.java:201)
at nettytests.logger.RequestAuditLogger.handleUpstream(RequestAuditLogger.java:32)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:456)
at org.jboss.netty.handler.ssl.SslHandler.exceptionCaught(SslHandler.java:554)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:426)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:47)
at org.jboss.netty.channel.Channels.write(Channels.java:605)
at org.jboss.netty.channel.Channels.write(Channels.java:572)
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:245)
at nettytests.http.snoop.HttpSnoopServerHandler.exceptionCaught(HttpSnoopServerHandler.java:201)
at nettytests.logger.RequestAuditLogger.handleUpstream(RequestAuditLogger.java:32)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:456)
at org.jboss.netty.handler.ssl.SslHandler.exceptionCaught(SslHandler.java:554)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:426)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:47)
at org.jboss.netty.channel.Channels.write(Channels.java:605)
at org.jboss.netty.channel.Channels.write(Channels.java:572)
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:245)
at nettytests.http.snoop.HttpSnoopServerHandler.exceptionCaught(HttpSnoopServerHandler.java:201)
at nettytests.logger.RequestAuditLogger.handleUpstream(RequestAuditLogger.java:32)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:456)
at org.jboss.netty.handler.ssl.SslHandler.exceptionCaught(SslHandler.java:554)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:426)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:47)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:343)
at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:274)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:194)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
...无限重复。
答案 0 :(得分：2)
无限循环很糟糕......我注意到你在finally块中调用了Channel.close（）。这种情况大多数情况发生在您可以向频道写一些内容之前。你应该使用
future.addListener（ChannelFutureListener.CLOSE）;
在写完东西后关闭频道。甚至应该在异常
上调用它