CODEWITHSUNDEEP
javaformstomcat
parvuselephantus
parvuselephantus

Reputation: 181

HttpServletRequest does not return null?

I have a form:

<form action='?hasScenario=1' method='post' enctype='multipart/form-data'>
 <input type='file' name='file'/>
 <input type='submit' />
</form>

In tomcat 8.0 I want to do:

private void handleRequest(HttpServletRequest request, HttpServletResponse response) throws IOException {
    Part filePart = request.getPart("file");
    ....
}

In documentation I see I should get null if user doesn't enter any value. I havn't (intentionally) configured anything special for multipart/file uploading in web.xml or server. But instead of null I get: java.lang.IllegalStateException: Unable to process parts as no multi-part configuration has been provided

I would like to handle nicely cases, when some parameters are not provided, how to do that? Catching and doing nothing on IllegalStateException is not nice way for me - in case of no parameter I'd like to ask user for file instead of scaring him with 'error/warning' words.

Upvotes: 1

Views: 851

Answers (1)

parvuselephantus
parvuselephantus

Reputation: 181

It is a great way to find answer myself - just ask question to others :)

multipart-config in web.xml is a must. So my servlet part looks currently like:

<servlet>
 <description>Scenario</description>
 <servlet-name>Scenario</servlet-name>
 <servlet-class>path-to-the-servlet</servlet-class>
 <multipart-config>
  <max-file-size>3145728</max-file-size>
  <max-request-size>5242880</max-request-size>
 </multipart-config>
</servlet>
<servlet-mapping>
 <servlet-name>Scenario</servlet-name>
 <url-pattern>/scenario</url-pattern>
</servlet-mapping>

Before calling getPart it's important to check there are any data, like with:

if (request.getContentType() != null)
    Part filePart = request.getPart("file");
    ...

And so finally filePart is null or a valid variable

Still I can't understand how have they made getParameter working in this post How to upload files to server using JSP/Servlet? but this is different story :)

Upvotes: 1

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