Best practice response.getOutputStream

Question

any comments on my code allowing the user to upload the file.

if(fileObject !=null)
response.setHeader("Content-disposition", "attachment; filename=\""+fileObject.getFilename()+"\"");
response.setContentType(fileObject.getFiletype());
response.setContentLength((int)fileObject.getFilesize().intValue());
try {
 if(response !=null && response.getOutputStream() !=null &&fileObject!=null && fileObject.getBinData() !=null ){
    OutputStream out = response.getOutputStream();
    out.write(fileObject.getBinData());
 }


} catch (IOException e) {
    throw new ApplicationRuntimeException(e);
}

Most of the time, I do not get below error. but once and for all, I get an error

29 Nov 2010 10:50:41,925 WARN [http-2020-2] - Unable to present exception page: getOutputStream() has already been called for this response
java.lang.IllegalStateException: getOutputStream() has already been called for this response
 at org.apache.catalina.connector.Response.getWriter(Response.java:610)

Answer 1

The exception message is clear:

Cannot submit an exception page : getOutputStream () has already been called for this answer
java.lang.IllegalStateException: getOutputStream () has already been called for this answer
on org.apache.catalina.connector.Response. getWriter (Response.java:610)

IOException , , servletcontainer , getWriter() . IOException , .

, IOException , . catch IOException API . throws .

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    FileObject fileObject = getItSomehow();
    if (fileObject != null && fileObject.getBinData() != null) {
        response.setHeader("Content-disposition", "attachment; filename=\"" + fileObject.getFilename() + "\"");
        response.setContentType(fileObject.getFiletype());
        response.setContentLength((int)fileObject.getFilesize().intValue());
        response.getOutputStream().write(fileObject.getBinData());
    } else {
        // ???
    }
}

Answer 2

response.getOutputStream() . , write.

try {
 OutputStream out = response.getOutputStream();
 if(response !=null && out !=null &&fileObject!=null && fileObject.getBinData() !=null ){
    out.write(fileObject.getBinData());
 }
} catch (IOException e) {
  throw new ApplicationRuntimeException(e);
}

Answer 3

? , ? response.getOutputStream()? fileObject, , ? ? , .

Answer 4

, ...

http://commons.apache.org/fileupload/apidocs/index.html?org/apache/commons/fileupload/util/package-summary.html