Hi Mark, a bit more follow-up on accessing the servlet InputStream:
You advised "You'd be better off dropping the call to in.ready() and doing
a blocking
read on the socket.....If you remove the call to
in.ready(), I'm fairly sure you'll see the warnings disappear."
I just thought I'd let you know, that prediction was absolutely correct.
On Thu, Aug 29, 2013 at 7:09 AM, Vince Stewart <stewart.vi...@gmail.com>wrote:
> Appreciate this a lot Mark.
>
> I'm pretty sure my previous code had a short sleep in each loop but
> thankfully, in-coming data rarely exceeds the Servlet InputBuffer size of
> 8192 so looping is rare.
>
> I have been trying to get to grips with the asynchronous stuff but have
> not got it going yet. The concept is very appealing. Thanks for your
> contributions.
>
>
> On Wed, Aug 28, 2013 at 11:00 PM, Mark Thomas <ma...@apache.org> wrote:
>
>> On 28/08/2013 09:41, Mark Thomas wrote:
>> > On 27/08/2013 03:40, Vince Stewart wrote:
>> >> hi all,
>> >> thought I would add some progress on this topic.
>> >> I have changed my method for reading from the HttpServletRequest
>> object but
>> >> the same warning message is thrown for every 8192 bytes read. I no
>> longer
>> >> regard my code to be suspect though am happy to be corrected. The
>> >> application operates completely normally except for the warning
>> message. The
>> >> code I am using to read the input is shown below.
>> >>
>> >> public void doPost(HttpServletRequest httpServletRequest.....etc
>> >> .......other code..............
>> >> char[] cbuf=new char[8192];
>> >> int i=0;
>> >> int requestLength=httpServletRequest.getContentLength();
>> >> BufferedReader in=httpServletRequest.getReader();
>> >> StringBuilder sb=new StringBuilder(requestLength);
>> >> while(sb.length()<requestLength){
>> >> if(in.ready()){
>> >> i=in.read(cbuf,0,reqLen);
>> >> }
>> >> sb.append(cbuf,0,i);
>> >> }
>> >> in.close();
>> >> String message=sb.toString();
>> >> //.....etc
>> >
>> > It looks like there is a possible Tomcat bug but the above code is not
>> > the way to read data from the client as it puts the thread into a tight
>> > loop while it is waiting for more data to arrive.
>>
>> I've just cleaned up the code for Tomcat 8.0.x to fix the bug that your
>> example highlighted. Thanks for such a clear problem statement that made
>> it very easy to track down the root cause of the issue. The fix will be
>> in 8.0.0-RC2 onwards.
>>
>> That said, my comments about there being a better way to do what you are
>> doing stand.
>>
>> Mark
>>
>> >
>> > You'd be better off dropping the call to in.ready() and doing a blocking
>> > read on the socket. The elapsed time should be the same (might even be a
>> > little less) and your CPU consumption during the read when the client is
>> > slow sending data will be significantly lower. If you remove the call to
>> > in.ready(), I'm fairly sure you'll see the warnings disappear.
>> >
>> > Ideally, you should look at non-blocking IO as supported by Servlet 3.1
>> > but that might be too big a change as it fundamentally changes how data
>> > is read and written.
>> >
>> > Mark
>> >
>> >
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>> >
>>
>>
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>>
>
>
> --
> Vince Stewart
>
--
Vince Stewart
