Upload file from HTML form through Servlet to Goog

2019-04-11 03:06发布

站内问答 / Java
759 2 5

My project has been created by GAE Plugin for Eclipse (without Maven) and i'm goint to post my code composed by:

home.jsp

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
    <title>Upload Test</title>
    </head>
    <body>
        <form action="/upload" method="post" name="putFile" id="putFile"
                enctype="multipart/form-data">
                <input type="file" name="myFile" id="fileName">
                <input type="submit" value="Upload">
        </form> 
    </body>
    </html>

UploadServlet.java:

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.nio.channels.Channels;
import java.util.Enumeration;
import java.util.logging.Logger;

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

import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import com.google.appengine.tools.cloudstorage.GcsFileOptions;
import com.google.appengine.tools.cloudstorage.GcsFilename;
import com.google.appengine.tools.cloudstorage.GcsOutputChannel;
import com.google.appengine.tools.cloudstorage.GcsService;
import com.google.appengine.tools.cloudstorage.GcsServiceFactory;
import com.google.appengine.tools.cloudstorage.RetryParams;

public class UploadServlet extends HttpServlet {

    private static final Logger log = Logger.getLogger(UploadServlet.class.getName());

    private final GcsService gcsService = GcsServiceFactory.createGcsService(new RetryParams.Builder()
    .initialRetryDelayMillis(10)
    .retryMaxAttempts(10)
    .totalRetryPeriodMillis(15000)
    .build());

    private String bucketName = "myBucketNameOnGoogleCloudStorage";

    /**Used below to determine the size of chucks to read in. Should be > 1kb and < 10MB */
      private static final int BUFFER_SIZE = 2 * 1024 * 1024;

    @SuppressWarnings("unchecked")
    @Override
    public void doPost(HttpServletRequest req, HttpServletResponse res)
            throws ServletException, IOException {

        String sctype = null, sfieldname, sname = null;
        ServletFileUpload upload;
        FileItemIterator iterator;
        FileItemStream item;
        InputStream stream = null;
        try {
            upload = new ServletFileUpload();
            res.setContentType("text/plain");

            iterator = upload.getItemIterator(req);
            while (iterator.hasNext()) {
                item = iterator.next();
                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());

                    sfieldname = item.getFieldName();
                    sname = item.getName();

                    sctype = item.getContentType();

                    GcsFilename gcsfileName = new GcsFilename(bucketName, sname);

                    GcsFileOptions options = new GcsFileOptions.Builder()
                    .acl("public-read").mimeType(sctype).build();

                    GcsOutputChannel outputChannel =
                            gcsService.createOrReplace(gcsfileName, options);

                    copy(stream, Channels.newOutputStream(outputChannel));

                    res.sendRedirect("/");
                }
            }
        } catch (Exception ex) {
            throw new ServletException(ex);
        }
    }

    private void copy(InputStream input, OutputStream output) throws IOException {
        try {
          byte[] buffer = new byte[BUFFER_SIZE];
          int bytesRead = input.read(buffer);
          while (bytesRead != -1) {
            output.write(buffer, 0, bytesRead);
            bytesRead = input.read(buffer);
          }
        } finally {
          input.close();
          output.close();
        }
      }

}

I tried also to set the maximumSize of the Upload using upload.setMaxSize(-1); or changing the BUFFER_SIZE from 2*1024*1024 into 200*1024*1024, but the issue stil occur. To be more specific, when the uploading reach the 100% I receive this message on the webpage:

Error: Request Entity Too Large Your client issued a request that was too large.

How can i fix that using JAVA and Google Cloud Storage Client Library for Java? (I'm not going to change drastically the Project with other Programming Languages)

Could you please help me to find a solution? Thank you so much!

2条回答
时光不老，我们不散
2楼-- · 2019-04-11 03:29

App Engine request limit is 32Mb. That's why your uploads are failing when you send a file > 32Mb. Checkout Quotas and Limits section.

You have two options for uploading files > 32Mb:

Or you could just use Google Drive and store only doc IDs in the datastore :)

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我欲成王，谁敢阻挡
3楼-- · 2019-04-11 03:51

I will suggest you to take a look at this great and sample example: http://docs.oracle.com/javaee/6/tutorial/doc/glraq.html A good idea will be to monitor the data stream to the server.

Hope it helps

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