How do I handle multipart form data? or How do I handle file uploads to my app?
You can obtain the uploaded file data from a multipart form post using classes from the Apache Commons FileUpload package. Specifically you may want to use FileItemStream, FileItermIterator and ServletFileUpload as illustrated below.
If you see a java.lang.NoClassDefFoundError after starting your application, make sure that the Apache Commons FileUpload JAR file has been copied to your war/WEB-INF/lib directory and added to your build path.
import org.apache.commons.fileupload.FileItemStream;import org.apache.commons.fileupload.FileItemIterator;import org.apache.commons.fileupload.servlet.ServletFileUpload;import java.io.InputStream;import java.io.IOException;import java.util.logging.Logger;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class FileUpload extends HttpServlet { private static final Logger log = Logger.getLogger(FileUpload.class.getName()); public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { try { ServletFileUpload upload = new ServletFileUpload(); res.setContentType("text/plain"); FileItemIterator iterator = upload.getItemIterator(req); while (iterator.hasNext()) { FileItemStream item = iterator.next(); InputStream stream = item.openStream(); if (item.isFormField()) { log.warning("Got a form field: " + item.getFieldName()); } else { log.warning("Got an uploaded file: " + item.getFieldName() + ", name = " + item.getName()); // You now have the filename (item.getName() and the // contents (which you can read from stream). Here we just // print them back out to the servlet output stream, but you // will probably want to do something more interesting (for // example, wrap them in a Blob and commit them to the // datastore). int len; byte[] buffer = new
