UploadServlet.java

package eu.geoknow.generator.servlets;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.codehaus.jackson.map.ObjectMapper;

import eu.geoknow.generator.utils.JsonResponse;

public class UploadServlet extends HttpServlet {

  private static final long serialVersionUID = 1L;
  private String filePath;
  private String tempData;
  private int maxFileSize = 1024 * 1024;
  private int maxMemSize = 4 * 1024;


  public void init() {
    // Get the file location where it would be stored.
    filePath = getServletContext().getInitParameter("file-upload");
    maxFileSize = Integer.parseInt(getServletContext().getInitParameter("max-file-size"));
    maxMemSize = Integer.parseInt(getServletContext().getInitParameter("max-mem-size"));
    tempData = getServletContext().getInitParameter("temp-data");
  }

  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {

    response.setContentType("application/json");
    PrintWriter out = response.getWriter();

    JsonResponse res = new JsonResponse();
    ObjectMapper mapper = new ObjectMapper();

    boolean isMultipartContent = ServletFileUpload.isMultipartContent(request);
    if (!isMultipartContent) {
      res.setStatus("FAIL");
      res.setMessage("Not a file.");
      mapper.writeValue(out, res);
      out.close();
      return;
    }

    // Directory where files will be saved
    ServletContext servletContext = getServletContext();

    File tmpDataDir =
        new File(servletContext.getRealPath(File.separator) + File.separator + tempData);
    if (!tmpDataDir.exists()) {
      tmpDataDir.mkdirs();
    }

    File seshdir = new File(servletContext.getRealPath(File.separator) + File.separator + filePath);
    if (!seshdir.exists()) {
      seshdir.mkdirs();
    }

    DiskFileItemFactory factory = new DiskFileItemFactory();
    // maximum size that will be stored in memory
    factory.setSizeThreshold(maxMemSize);
    // Location to save data that is larger than maxMemSize.
    factory.setRepository(tmpDataDir);

    ServletFileUpload upload = new ServletFileUpload(factory);
    // maximum file size to be uploaded.
    upload.setSizeMax(maxFileSize);
    try {
      List<FileItem> fields = upload.parseRequest(request);

      Iterator<FileItem> it = fields.iterator();
      if (!it.hasNext()) {
        res.setStatus("FAIL");
        res.setMessage("No fields found");
        mapper.writeValue(out, res);
        out.close();
        return;
      }


      for (FileItem diskFileItem : fields) {
        // Exclude the form fields
        if (diskFileItem.isFormField()) {
          continue;
        }

        byte[] fileBytes = diskFileItem.get();
        File file = new File(seshdir, diskFileItem.getName());
        if (!file.exists())
          file.createNewFile();

        try {
          FileOutputStream fileOutputStream = new FileOutputStream(file);
          fileOutputStream.write(fileBytes);
          fileOutputStream.flush();
          fileOutputStream.close();


        } catch (FileNotFoundException e) {
          res.setStatus("FAIL");
          res.setMessage(e.getMessage());
          return;
        }

        res.addResult(file.getAbsolutePath());
      }
      res.setStatus("SUCESS");
      res.setMessage("Successfuly uploaded");

    } catch (FileUploadException e) {
      res.setStatus("FAIL");
      res.setMessage(e.getMessage());
    }

    mapper.writeValue(out, res);
    out.close();
  }
}