java - Upload a Word Document with JSP -

the program working on allows user browse files on server , download them. download wrote jsp upload content client. passed name of file , sends contents. code have bellow works great text files when try download , open word document understand binary file text, weird squares, , error message ms word. not sure why incorrectly reading binary data. appreciated.

    <%@ page import="java.io.*" %>  <%     final file app_root = new file(com.mdi.core.config.processconfiguration.getinstance().getstringvalue("app_root"));     file f = new file(request.getparameter("path"));      file parent = f;     boolean valid = false;     while(!valid && (parent = parent.getparentfile()) != null)     {         valid = parent.equals(app_root);     }     if(!valid)     {         response.senderror(403, "you can not download file!");         return;     }      response.addheader("content-disposition","attachment; filename="+f.getname());      response.setcontentlength((int)f.length());     outputstream os = response.getoutputstream();     response.setcontenttype(java.net.urlconnection.guesscontenttypefromname(f.getname()));     inputstream fin = null;     try     {         fin = new fileinputstream(f);         byte[] buff = new byte[512];         int read;         while((read = fin.read(buff)) != -1)             os.write(buff, 0, read);     }     catch(exception ex)     {         ex.printstacktrace();     }         {         if(fin != null) fin.close();     }        %> 

also error in standard output.

java.net.protocolexception: exceeded stated content-length of: '40220' bytes     @ weblogic.servlet.internal.servletoutputstreamimpl.checkcl(servletoutputstreamimpl.java:200)     @ weblogic.servlet.internal.servletoutputstreamimpl.write(servletoutputstreamimpl.java:146)     @ jsp_servlet._mdi._html._file_upload.__default_file_upload._jspservice(__default_file_upload.java:101)     @ weblogic.servlet.jsp.jspbase.service(jspbase.java:34)     @ weblogic.servlet.internal.stubsecurityhelper$servletserviceaction.run(stubsecurityhelper.java:227)     @ weblogic.servlet.internal.stubsecurityhelper.invokeservlet(stubsecurityhelper.java:125)     @ weblogic.servlet.internal.servletstubimpl.execute(servletstubimpl.java:300)     @ weblogic.servlet.internal.tailfilter.dofilter(tailfilter.java:26)     @ weblogic.servlet.internal.filterchainimpl.dofilter(filterchainimpl.java:56)     @ com.mdi.core.utils.http.securityfilter.dofilter(securityfilter.java:154)     @ weblogic.servlet.internal.filterchainimpl.dofilter(filterchainimpl.java:56)     @ com.mdi.core.utils.http.responseheaderfilter.dofilter(responseheaderfilter.java:69)     @ weblogic.servlet.internal.filterchainimpl.dofilter(filterchainimpl.java:56)     @ weblogic.servlet.internal.webappservletcontext$servletinvocationaction.wraprun(webappservletcontext.java:3715)     @ weblogic.servlet.internal.webappservletcontext$servletinvocationaction.run(webappservletcontext.java:3681)     @ weblogic.security.acl.internal.authenticatedsubject.doas(authenticatedsubject.java:321)     @ weblogic.security.service.securitymanager.runas(securitymanager.java:120)     @ weblogic.servlet.internal.webappservletcontext.securedexecute(webappservletcontext.java:2277)     @ weblogic.servlet.internal.webappservletcontext.execute(webappservletcontext.java:2183)     @ weblogic.servlet.internal.servletrequestimpl.run(servletrequestimpl.java:1454)     @ weblogic.work.executethread.execute(executethread.java:209)     @ weblogic.work.executethread.run(executethread.java:178) <jun 27, 2014 10:46:07 edt> <error> <http> <bea-101083> <connection failure. java.net.protocolexception: didn't meet stated content-length, wrote: '39942' bytes instead of stated: '40220' bytes.     @ weblogic.servlet.internal.servletoutputstreamimpl.ensurecontentlength(servletoutputstreamimpl.java:446)     @ weblogic.servlet.internal.servletresponseimpl.ensurecontentlength(servletresponseimpl.java:1432)     @ weblogic.servlet.internal.servletresponseimpl.send(servletresponseimpl.java:1511)     @ weblogic.servlet.internal.servletrequestimpl.run(servletrequestimpl.java:1462)     @ weblogic.work.executethread.execute(executethread.java:209)     truncated. see log file complete stacktrace >  <jun 27, 2014 10:46:07 edt> <error> <http> <bea-101104> <servlet execution in servlet context "servletcontext@1188950474[app:trade module:ta15 path:/ta15 spec-version:null]" failed, java.net.protocolexception: didn't meet stated content-length, wrote: '39942' bytes instead of stated: '40220' bytes.. java.net.protocolexception: didn't meet stated content-length, wrote: '39942' bytes instead of stated: '40220' bytes.     @ weblogic.servlet.internal.servletoutputstreamimpl.ensurecontentlength(servletoutputstreamimpl.java:446)     @ weblogic.servlet.internal.servletresponseimpl.ensurecontentlength(servletresponseimpl.java:1432)     @ weblogic.servlet.internal.servletresponseimpl.send(servletresponseimpl.java:1511)     @ weblogic.servlet.internal.servletrequestimpl.run(servletrequestimpl.java:1462)     @ weblogic.work.executethread.execute(executethread.java:209)     truncated. see log file complete stacktrace 

very important remove jsp own whitespace output:

<%@ page contenttype="application/octet" import="java.io.*" %><% %> 

no white space, , no newline on last line. tip: use servlet.

somehow os.flush() still needs done.

after comment @boristhespide: forget flushing. think spaces caused problem, added content type binary data.