如何使用 Java API 将超过 32Mb 的文件上传到谷歌云存储

Question

我正在努力创建一个应用程序，该应用程序将使用 java API 将苍蝇从本地机器上传到谷歌云存储。但我面临的问题是 API 不允许我上传超过 32 Mb 的文件，而我要上传的文件超过 100 Mb 或者可能是 200 Mb。 我非常感谢这方面的帮助，并想知道将文件上传到 Google Cloud Storage 的最佳做法或 API。

我正在使用以下代码。

上传文件Servlet.java

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.nio.channels.Channels;

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.api.blobstore.BlobKey;
import com.google.appengine.api.users.User;
import com.google.appengine.api.users.UserService;
import com.google.appengine.api.users.UserServiceFactory;
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;
import com.igt.service.StorageService;

public class UploadFileServlet extends HttpServlet {

private static final long serialVersionUID = 1L;
private StorageService storage = new StorageService();
private static int BUFFER_SIZE = 1024 * 1024 * 10;
public static final String BUCKET_NAME = "my-bucket-test";
private final GcsService gcsService =  GcsServiceFactory.createGcsService(RetryParams.getDefaultInstance());

@Override
public void doPost(HttpServletRequest req, HttpServletResponse resp)
        throws IOException {

    UserService userService = UserServiceFactory.getUserService();
    User user = userService.getCurrentUser();

    if (user != null) {
        resp.setContentType("text/plain");
        resp.getWriter().println("Now see here your file content, that you have uploaded on storage..");

        ServletFileUpload upload = new ServletFileUpload();
        FileItemIterator iter;
        try {
            iter = upload.getItemIterator(req);
            while (iter.hasNext()) {
                FileItemStream item = iter.next();
                String fileName = item.getName();
                String mime = item.getContentType();

                GcsFileOptions options = new GcsFileOptions.Builder()
                .acl("public_read")
                .mimeType(mime)
                .build();

                GcsFilename filename = new GcsFilename(BUCKET_NAME, fileName);

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

                // Writing the file to input stream
                InputStream is = new BufferedInputStream(item.openStream());

                // Copying InputStream to GcsOutputChannel
                try {
                    copy(is, Channels.newOutputStream(outputChannel));
                } finally {
                    outputChannel.close();
                    is.close();
                }                                           

                resp.getWriter().println("File uploading done");
                System.out.println("File uploading done");

                // resp.getWriter().println("READ:" +
                // storage.readTextFileOnly(fileName));
                BlobKey key = storage.getBlobkey(fileName);
                if (key != null) {
                    resp.sendRedirect("/serve?blob-key=" + key.getKeyString());
                } else {
                    resp.sendRedirect("/login");
                }
                resp.sendRedirect("/login");
            }
        } catch (Exception e) {
            e.printStackTrace(resp.getWriter());
            System.out.println("Exception::" + e.getMessage());
            e.printStackTrace();
        }
    } else {
        resp.sendRedirect(userService.createLoginURL(req.getRequestURI()));
    }
}

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

}

StorageService.java

import java.io.BufferedOutputStream;
import java.nio.channels.Channels;
import java.util.logging.Logger;

import com.google.appengine.api.blobstore.BlobKey;
import com.google.appengine.api.blobstore.BlobstoreService;
import com.google.appengine.api.blobstore.BlobstoreServiceFactory;
import com.google.appengine.api.files.AppEngineFile;
import com.google.appengine.api.files.FileService;
import com.google.appengine.api.files.FileServiceFactory;
import com.google.appengine.api.files.FileWriteChannel;
import com.google.appengine.api.files.GSFileOptions.GSFileOptionsBuilder;

@SuppressWarnings("deprecation")

public class StorageService {

private static final Logger log = Logger.getLogger(StorageService.class.getName());
private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();  


public BlobKey getBlobkey(String filename) {
    BlobKey bk = blobstoreService.createGsBlobKey("/gs/sample-bucket/"  + filename);
    return bk;
}

}

login.jsp

 <form action="/upload" method="post" enctype="multipart/form-data">

    <div><input name = "file" type="file" value="Upload" /></div>    
    <div><input type="submit" value="Upload File" /></div>
  </form>

Answer 1

来自用户的单个 AppEngine 连接不能传输超过 32 MB。相反，您应该让您的用户将文件直接上传到 Google Cloud Storage。 Google Cloud Storage 支持标准 HTML 表单上传。此处提供了完整的文档：https://developers.google.com/storage/docs/reference-methods#postobject

让用户页面提交一个表单帖子，其中包含指定存储桶和对象名称的所有适当表单字段。存储桶需要可公开写入，或者您需要包含适当的签名字段。

将“success_action_redirect”字段设置为 AppEngine URL。上传成功后，浏览器会重定向到这个网址。