CODEWITHSUNDEEP
tomcatservlet-3.0form-dataserver.xml
astonia
astonia

Reputation: 548

maxPostSize in tomcat's configuration

According to Tomcat7's documentation, setting maxPostSize in Connector to a value less than or equal to 0 may disable the limit of the size of a post request. But in fact, when I set it to 0, uploading a file in multipart/form-data enctype still got the error of exceeding the max size limit. When I set it to -1, no limit occurs, but other strange things happened.

Here is the HTML codes for uploading a file with a text input field:

<html>
    <head>
    </head>
    <body>
        test
        <form action="UploadFile" method="post" enctype="multipart/form-data">
            <input type="text" name="description" />
            <input type="file" name="file" />
            <input type="submit" />
        </form>
    </body>
</html>

The server side codes are using Servlet 3.0 api:

import javax.servlet.http.Part;
import javax.servlet.annotation.MultipartConfig;
import java.io.InputStream;
import java.io.FileOutputStream;
import java.io.PrintWriter;
import java.util.Collection;
import com.google.gson.JsonObject;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;


    @MultipartConfig(fileSizeThreshold=1024*1024*10,    // 10 MB
                     maxFileSize=1024*1024*50,          // 50 MB
                     maxRequestSize=1024*1024*100)      // 100 MB
    public class UploadFile extends HttpServlet
    {
        public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws Exception
        {
            // Retrieves <input type="text" name="description">
            String description = request.getParameter("description"); 

            JsonObject jsonRet = new JsonObject();
            JsonArray jsonArray = new JsonArray();
            jsonRet.add("files", jsonArray);
            try {
                Collection<Part> allParts = request.getParts(); // Retrieves all uploaded files
                for (Part filePart : allParts) {
                    String filename = null;
                    if (filePart == null || filePart.getContentType() == null) {
                        System.out.println("part is null");
                        continue;
                    } else {
                        filename = getFilename(filePart);
                    }
                    System.out.println(filename);
                    InputStream filecontent = filePart.getInputStream();
                    FileOutputStream fos = new FileOutputStream("/tmp/uploadfile/" + filename);
                    byte[] buffer = new byte[1024 * 4];
                    int c = 0;
                    while ((c = filecontent.read(buffer)) != -1) {
                        fos.write(buffer, 0, c);
                    }
                    JsonObject jsonObj = new JsonObject();
                    jsonObj.addProperty("name", filename);
                    jsonObj.addProperty("size", filePart.getSize());
                    jsonObj.addProperty("url", "the-url");
                    jsonObj.addProperty("thumbnail_url", "the-thumb");
                    jsonObj.addProperty("delete_url", "the-delete");
                    jsonObj.addProperty("delete_type", "DELETE");
                    jsonArray.add(jsonObj);
                }

                response.setCharacterEncoding("utf-8");
                response.setContentType("text/plain");
                PrintWriter writer = response.getWriter();
                writer.write(jsonRet.toString());
            } catch (Exception e) {
                throw e;
            }

        }

        private static String getFilename(Part part) 
        {
            for (String cd : part.getHeader("Content-Disposition").split(";")) {
                if (cd.trim().startsWith("filename")) {
                    String filename = cd.substring(cd.indexOf('=') + 1).trim().replace("\"", "");
                    return filename.substring(filename.lastIndexOf('/') + 1).substring(filename.lastIndexOf('\\') + 1); // MSIE fix.
                }
            }
            return null;
        }

If I set maxPostSize to -1, and leave the text field "description" to blank, it responses:

java.lang.String.<init>(String.java:481)
    org.apache.tomcat.util.http.fileupload.disk.DiskFileItem.getString(DiskFileItem.java:328)
    org.apache.catalina.connector.Request.parseParts(Request.java:2752)
    org.apache.catalina.connector.Request.parseParameters(Request.java:3083)
    org.apache.catalina.connector.Request.getParameter(Request.java:1151)
    org.apache.catalina.connector.RequestFacade.getParameter(RequestFacade.java:384)
    com.bluepyxis.servlet.HttpServletRequestWrapper.getParameter(HttpServletRequestWrapper.java:40)
    com.bluepyxis.actions.UploadFile.process(UploadFile.java:34)
......

If I set maxPostSize to a positive value or fill some texts in the description field, everything works fine.

So I wonder, why could this happen? And is there any way to set the post size unlimited while preventing the NullPointerException for an unfilled field?

Thanks in advance.

Upvotes: 3

Views: 6991

Answers (1)

Mark Thomas
Mark Thomas

Reputation: 16615

The docs aren't quite right. maxPostSize=0 results in a limit of zero. -1 is the correct value for no limit. I'll get that fixed shortly.

Upvotes: 5

Related Questions