I'm creating a web app using Java servlets and JSPs and I want to create an upload form in JSP for my clients to be able to upload and download stuff. I'm using Cloud Storage and my default bucket to upload stuff. I followed Google's tutorial on Reading and Writing to Google Cloud Storage .
This is my Servlet:
public class Create extends HttpServlet {
public static final boolean SERVE_USING_BLOBSTORE_API = false;
private final GcsService gcsService = GcsServiceFactory.createGcsService(new RetryParams.Builder()
.initialRetryDelayMillis(10)
.retryMaxAttempts(10)
.totalRetryPeriodMillis(15000)
.build());
@Override
public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
GcsFilename fileName = getFileName(req);
if (SERVE_USING_BLOBSTORE_API) {
BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
BlobKey blobKey = blobstoreService.createGsBlobKey(
"/gs/" + fileName.getBucketName() + "/" + fileName.getObjectName());
blobstoreService.serve(blobKey, resp);
} else {
GcsInputChannel readChannel = gcsService.openPrefetchingReadChannel(fileName, 0, BUFFER_SIZE);
copy(Channels.newInputStream(readChannel), resp.getOutputStream());
}
}
@Override
public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
GcsFileOptions instance = GcsFileOptions.getDefaultInstance();
GcsFilename fileName = getFileName(req);
GcsOutputChannel outputChannel;
outputChannel = gcsService.createOrReplace(fileName, instance);
copy(req.getInputStream(), Channels.newOutputStream(outputChannel));
}
private GcsFilename getFileName(HttpServletRequest req) {
String[] splits = req.getRequestURI().split("/", 4);
if (!splits[0].equals("") || !splits[1].equals("gcs")) {
throw new IllegalArgumentException("The URL is not formed as expected. " +
"Expecting /gcs/<bucket>/<object>");
}
return new GcsFilename(splits[2], splits[3]);
}
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 can upload and download successfully, but only text and not real files like images, pdfs, etc., which is my problem. This tutorial is for reading and writing text but i want to upload real files. As you can see from my jsp the enctype is "text/plain"
:
<form action="/index.html" enctype="text/plain" method="get" name="putFile" id="putFile">
<div>
Bucket: <input type="text" name="bucket" />
File Name: <input type="text" name="fileName" />
<br /> File Contents: <br />
<textarea name="content" id="content" rows="3" cols="60"></textarea>
<br />
<input type="submit" onclick='uploadFile(this)' value="Upload Content" />
</div>
</form>
I tried to change it to "multipart/form-data" and put a
<input name="content" id="content" type="file">
but this does not upload the real file only the fake path of the file. And I want to know how to upload real files, any help would be appreciated.
Here is one example on how to upload blobs to Cloud Storage:
First you initialize the storage with these lines:
private static Storage storage = null;
// [START init]
static {
storage = StorageOptions.getDefaultInstance().getService();
}
// [END init]
You may change the code to accept different file extensions according to your needs on the getImageUrl
method in the line String[] allowedExt = {"jpg", "jpeg", "png", "gif"};
/**
* Extracts the file payload from an HttpServletRequest, checks that the file extension
* is supported and uploads the file to Google Cloud Storage.
*/
public String getImageUrl(HttpServletRequest req, HttpServletResponse resp,
final String bucket) throws IOException, ServletException {
Part filePart = req.getPart("file");
final String fileName = filePart.getSubmittedFileName();
String imageUrl = req.getParameter("imageUrl");
// Check extension of file
if (fileName != null && !fileName.isEmpty() && fileName.contains(".")) {
final String extension = fileName.substring(fileName.lastIndexOf('.') + 1);
String[] allowedExt = {"jpg", "jpeg", "png", "gif"};
for (String s : allowedExt) {
if (extension.equals(s)) {
return this.uploadFile(filePart, bucket);
}
}
throw new ServletException("file must be an image");
}
return imageUrl;
}
Here a timestamp is appended in the filename which can be a good idea if you want to make the filename unique.
/**
* Uploads a file to Google Cloud Storage to the bucket specified in the BUCKET_NAME
* environment variable, appending a timestamp to end of the uploaded filename.
*/
@SuppressWarnings("deprecation")
public String uploadFile(Part filePart, final String bucketName) throws IOException {
DateTimeFormatter dtf = DateTimeFormat.forPattern("-YYYY-MM-dd-HHmmssSSS");
DateTime dt = DateTime.now(DateTimeZone.UTC);
String dtString = dt.toString(dtf);
final String fileName = filePart.getSubmittedFileName() + dtString;
// the inputstream is closed by default, so we don't need to close it here
BlobInfo blobInfo =
storage.create(
BlobInfo
.newBuilder(bucketName, fileName)
// Modify access list to allow all users with link to read file
.setAcl(new ArrayList<>(Arrays.asList(Acl.of(User.ofAllUsers(), Role.READER))))
.build(),
filePart.getInputStream());
// return the public download link
return blobInfo.getMediaLink();
}
In this documentation you'll find more details: https://cloud.google.com/java/getting-started/using-cloud-storage#uploading_blobs_to_cloud_storage
The complete code for this example is in github: https://github.com/GoogleCloudPlatform/getting-started-java/blob/master/bookshelf/3-binary-data/src/main/java/com/example/getstarted/util/CloudStorageHelper.java
I found a solution.
This is my JSP:
<form action="/create" enctype="multipart/form-data" method="post" name="putFile" id="putFile">
<div>
File Name: <input type="text" name="fileName" />
<br /> File Contents: <br />
<input type="submit" value="Upload Content" />
</div>
</form>
When i submit the form, it goes into this Servlet:
@Override
public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
Part filePart = req.getPart("content"); /*Get file from jsp*/
/*Get file name of file from jsp*/
String name = Paths.get(filePart.getSubmittedFileName()).getFileName().toString();
GcsFileOptions instance = GcsFileOptions.getDefaultInstance();
GcsFilename fileName = new GcsFilename(BUCKET_NAME, name);
GcsOutputChannel outputChannel;
outputChannel = gcsService.createOrReplace(fileName, instance);
/*Pass the file to copy function, wich uploads the file to cloud*/
copy(filePart.getInputStream(), Channels.newOutputStream(outputChannel));
req.getRequestDispatcher("download.jsp").forward(req, resp);
}
private GcsFilename getFileName(HttpServletRequest req) {
String[] splits = req.getRequestURI().split("/", 4);
if (!splits[0].equals("") || !splits[1].equals("gcs")) {
throw new IllegalArgumentException("The URL is not formed as expected. " +
"Expecting /gcs/<bucket>/<object>");
}
return new GcsFilename(splits[2], splits[3]);
}
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();
}
}
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