我正在使用Jersey,可以上传文件,也可以将虚拟数据块写入数据存储区。但是,我卡在了将上传的文件写入数据存储区的问题上。
@Path("/blob/")
public class UploadFileService {
@POST
@Path("/upload/")
@Consumes(MediaType.MULTIPART_FORM_DATA)
public Response uploadFile(@FormDataParam("file") InputStream stream, @FormDataParam("file") FormDataContentDisposition disposition) throws IOException {
storeBlob();
return Response.ok().build();
}
public void storeBlob() throws IOException{
// Get a file service
FileService fileService = FileServiceFactory.getFileService();
// Create a new Blob file with mime-type "text/plain"
AppEngineFile file = fileService.createNewBlobFile("text/plain");
// Open a channel to write to it
boolean lock = false;
FileWriteChannel writeChannel = fileService.openWriteChannel(file, lock);
// Different standard Java ways of writing to the channel
// are possible. Here we use a PrintWriter:
PrintWriter out = new PrintWriter(Channels.newWriter(writeChannel, "UTF8"));
out.println("The woods are lovely dark and deep.");
out.println("But I have promises to keep.");
// Close without finalizing and save the file path for writing later
out.close();
String path = file.getFullPath();
// Write more to the file in a separate request:
file = new AppEngineFile(path);
// This time lock because we intend to finalize
lock = true;
writeChannel = fileService.openWriteChannel(file, lock);
// This time we write to the channel directly
writeChannel.write(ByteBuffer.wrap
("And miles to go before I sleep.".getBytes()));
// Now finalize
writeChannel.closeFinally();
// Later, read from the file using the Files API
lock = false; // Let other people read at the same time
FileReadChannel readChannel = fileService.openReadChannel(file, false);
// Again, different standard Java ways of reading from the channel.
BufferedReader reader =
new BufferedReader(Channels.newReader(readChannel, "UTF8"));
String line = reader.readLine();
// line = "The woods are lovely dark and deep."
readChannel.close();
// Now read from the file using the Blobstore API
BlobKey blobKey = fileService.getBlobKey(file);
BlobstoreService blobStoreService = BlobstoreServiceFactory.getBlobstoreService();
String segment = new String(blobStoreService.fetchData(blobKey, 30, 40));
}
}