为什么我的文件没有上传到我的Java Servlet？

Question

well I'm trying to upload a file to my servlet from the web interface. I've been using Apache Commons FileUpload by following a tutorial and integrating it into my servlet. Somehow I can't manage to get the file uploaded.

Here's my form in the web page:

<form class="well" action="GenTreeUploader" method="post" enctype="multipart/form-data">
        <label>Choose your file:</label>
        <center><input type="file" class="input-xlarge" name="wordfile"></center><br>
        <center><span class="help-block">Note: after clicking "Upload file!" all of the data contained in the file will be uploaded to the database</span></center><br>
        <center><input class="btn btn-primary" type="submit" value="Upload file!"></center>  
        <input type="text" name="tester" value="xoxoxo" />
        <input type="hidden" name="action" value="startUpload" />
    </form>

Then here's my code part of the servlet that should handle the file upload from the request:

public void artiUpload(HttpServletRequest request, HttpServletResponse response, HtmlWriter writer) throws ServletException, IOException {
    System.out.println("I'm in upload");
    PrintWriter out = response.getWriter();
    // Check that we have a file upload request
    boolean isMultipart = ServletFileUpload.isMultipartContent(request);
    // Create a factory for disk-based file items

    // Create a factory for disk-based file items
    DiskFileItemFactory factory = new DiskFileItemFactory();

    // Set factory constraints
    factory.setSizeThreshold(maxMemSize);
    factory.setRepository(new File(htmlPath.toString()));
    System.out.println("File path: " + htmlPath.toString());

    // Create a new file upload handler
    ServletFileUpload upload = new ServletFileUpload(factory);

    // Set overall request size constraint
    upload.setSizeMax(maxFileSize);
    System.out.println("Max file size: " + maxFileSize);
    System.out.println("Max file size in memory: " + maxMemSize);
    List items = null;
    try {
        // Parse the request
        items = upload.parseRequest(request);
        System.out.println("Items found: " + items.size());
        out.write(writer.printCenter("File uploading done"));
    } catch (FileUploadException ex) {
        Logger.getLogger(GenTreeUploader.class.getName()).log(Level.SEVERE, null, ex);
        out.write(writer.printCenter("File uploading failed"));
    }
}

And here is the Tomcat server log I get from this servlet method:

I'm in upload
File path: D:\Dropbox\StudiesNew\NetbeansProjects\GenTreeUploader\build\web\WEB-INF\classes\Html
Max file size: 10485760
Max file size in memory: 2097152
Items found: 0

Well I'm also getting some parameters from the request by using: action = request.getParameter(actionText);

Works fine with normal parameters, but the file doesn't get uploaded. I believe after parsing the list should have one item in this case, it shows 0...

Can anyone help? Thanks.

The full log is this?

 Using CATALINA_BASE:   "C:\Users\Arturas\.netbeans\7.1.2\apache-tomcat-7.0.22.0_base"
Using CATALINA_HOME:   "C:\Program Files\Apache Software Foundation\Apache Tomcat 7.0.22"
Using CATALINA_TMPDIR: "C:\Users\Arturas\.netbeans\7.1.2\apache-tomcat-7.0.22.0_base\temp"
Using JRE_HOME:        "C:\Program Files\Java\jdk1.7.0_03"
Using CLASSPATH:       "C:\Program Files\Apache Software Foundation\Apache Tomcat 7.0.22\bin\bootstrap.jar;C:\Program Files\Apache Software Foundation\Apache Tomcat 7.0.22\bin\tomcat-juli.jar"
Bir 05, 2012 2:45:06 AM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Java\jdk1.7.0_03\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:\Program Files\Common Files\Microsoft Shared\Windows Live;C:\Program Files (x86)\Common Files\Microsoft Shared\Windows Live;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Windows Live\Shared;C:\Program Files\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files\Microsoft SQL Server\110\DTS\Binn\;C:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\ManagementStudio\;C:\Program Files (x86)\Microsoft SQL Server\110\DTS\Binn\;C:\Program Files\MATLAB\R2010b\runtime\win64;C:\Program Files\MATLAB\R2010b\bin;.
Bir 05, 2012 2:45:07 AM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-bio-8084"]
Bir 05, 2012 2:45:07 AM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-bio-8009"]
Bir 05, 2012 2:45:07 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 865 ms
Bir 05, 2012 2:45:07 AM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
Bir 05, 2012 2:45:07 AM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.22
Bir 05, 2012 2:45:07 AM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor GenTreeUploader.xml from C:\Users\Arturas\.netbeans\7.1.2\apache-tomcat-7.0.22.0_base\conf\Catalina\localhost
Bir 05, 2012 2:45:08 AM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor manager.xml from C:\Users\Arturas\.netbeans\7.1.2\apache-tomcat-7.0.22.0_base\conf\Catalina\localhost
Bir 05, 2012 2:45:08 AM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor mrweb.xml from C:\Users\Arturas\.netbeans\7.1.2\apache-tomcat-7.0.22.0_base\conf\Catalina\localhost
Bir 05, 2012 2:45:08 AM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor ROOT.xml from C:\Users\Arturas\.netbeans\7.1.2\apache-tomcat-7.0.22.0_base\conf\Catalina\localhost
Bir 05, 2012 2:45:08 AM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-bio-8084"]
Bir 05, 2012 2:45:08 AM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-bio-8009"]
Bir 05, 2012 2:45:08 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 1396 ms
I'm in upload
File path: D:\Dropbox\StudiesNew\NetbeansProjects\GenTreeUploader\build\web\WEB-INF\classes\Html
Max file size: 10485760
Max file size in memory: 2097152
Items found: 0

Answer 1

It will fail that way when the request body has already been parsed beforehand by calling getParameter() , getReader() or getInputStream() methods on the request inside the doPost() method of the very same servlet or inside the doFilter() method of one of the servlet filters which also runs on the same request. Another possible cause is that you're nesting HTML <form> elements, but the behaviour is browser dependent.

By the way, the HTML <center> element is deprecated since 1998. Get rid of it and use CSS instead.

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Update : your update confirms that you're calling getParameter() on the request . You should not do that when it's a multipart/form-data request. You should instead use the very same Apache Commons FileUpload API to collect normal form fields. See also How to upload files to server using JSP/Servlet?