download stream gets broken

[Robert Garrido]

Hi all,

I have a file download servlet running on Tomcat, the code is

    public void service(HttpServletRequest request, HttpServletResponse response) throws IOException {
        byte buf[] = new byte[1024 * 4];
        try {
            File file = new File(realFilename);
            int size = (int) file.length();
            BufferedInputStream realFile = new BufferedInputStream(new FileInputStream(file));
            OutputStream out = response.getOutputStream();
            response.setContentLength(size);
            while (true) {
                int count = realFile.read(buf);
                if (count == -1) {
                    break;
                }
                out.write(buf, 0, count);
            }
            out.flush();
        } catch (FileNotFoundException e) {
            logger.error("Stream download failed, file not found: " + realFilename, e);
            response.sendError(404);
        } catch (Exception e) {
            logger.error("DownloadException:", e);
        }
    }

However once in a while I get an error that prevents files from being downloaded:


DownloadException: java.net.SocketException: Broken pipe
at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:366)
at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:432)
at org.apache.tomcat.util.buf.ByteChunk.append(ByteChunk.java:347)
at org.apache.catalina.connector.OutputBuffer.writeBytes(OutputBuffer.java:392)
at org.apache.catalina.connector.OutputBuffer.write(OutputBuffer.java:381)
at org.apache.catalina.connector.CoyoteOutputStream.write(CoyoteOutputStream.java:89)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:113)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.net.SocketException: Broken pipe
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
at org.apache.coyote.http11.InternalOutputBuffer.realWriteBytes(InternalOutputBuffer.java:750)
at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:432)
at org.apache.tomcat.util.buf.ByteChunk.append(ByteChunk.java:347)
at org.apache.coyote.http11.InternalOutputBuffer$OutputStreamOutputBuffer.doWrite(InternalOutputBuffer.java:773)
at org.apache.coyote.http11.filters.IdentityOutputFilter.doWrite(IdentityOutputFilter.java:118)
at org.apache.coyote.http11.InternalOutputBuffer.doWrite(InternalOutputBuffer.java:583)
at org.apache.coyote.Response.doWrite(Response.java:560)
at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:361)
... 23 more

Tomcat connector looks like this:

        <Connector port="8088"
                disableUploadTimeout="true"
                enableLookups="false"
                acceptCount="10000"
                connectionTimeout="120000"
                maxKeepAliveRequests="20"
                maxSpareThreads="300"
                maxThreads="300"
                minSpareThreads="100"
                strategy="ms"
                threadPriority="java.lang.Thread#MAX_PRIORITY"
                tcpNoDelay="true"
                protocol="org.apache.coyote.http11.Http11Protocol"
                compression="on"
                server=""
                compressableMimeType="text/html,text/xml,text/plain,text/css,text/javascript"
                clockless="false"/>

How can I prevent such an error? Thanks!!!

[Madhan Sundararajan Devaki]

In line number 2, do not initialize the byte array.
In line number 5, change the data type to long and remove the type-cast.
After line number 5, initialise the byte array' size with the value of "size" variable in line number 5.

[Robert Garrido]

Thanks! It's better now...