[英]Upload file to Google cloud storage from Google App Engine (Java)
[英]How to properly upload (image) file to Google Cloud Storage using Java App Engine?
我有一個使用Java(sdk 1.9.7)的Google App Engine實例,它已連接到Google Cloud Storage。 我能夠成功接收請求的輸入並將其輸出到我的Google雲存儲桶中的文件/對象。 這是我的servlet代碼:
public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
// read the input stream
byte[] buffer = new byte[1024];
List<byte[]> allBytes = new LinkedList<byte[]>();
InputStream reader = req.getInputStream();
while(true) {
int bytesRead = reader.read(buffer);
if (bytesRead == -1) {
break; // have a break up with the loop.
} else if (bytesRead < 1024) {
byte[] temp = Arrays.copyOf(buffer, bytesRead);
allBytes.add(temp);
} else {
allBytes.add(buffer);
}
}
// init the bucket access
GcsService gcsService = GcsServiceFactory.createGcsService(RetryParams.getDefaultInstance());
GcsFilename filename = new GcsFilename("my-bucket", "my-file");
Builder fileOptionsBuilder = new GcsFileOptions.Builder();
fileOptionsBuilder.mimeType("text/html"); // or "image/jpeg" for image files
GcsFileOptions fileOptions = fileOptionsBuilder.build();
GcsOutputChannel outputChannel = gcsService.createOrReplace(filename, fileOptions);
// write file out
BufferedOutputStream outStream = new BufferedOutputStream(Channels.newOutputStream(outputChannel));
for (byte[] b : allBytes) {
outStream.write(b);
}
outStream.close();
outputChannel.close();
}
當我執行curl POST命令之類的操作時,如果我直接將其直接輸入數據,則效果很好,如下所示:
curl --data "someContentToBeRead" http://myAppEngineProj.appspot.com/myServlet
我可以看到我輸入的確切字符串,“someContentToBeRead”。
但是,當我放入文件時,如下所示:
curl -F file=@"picture.jpg" http://myAppEngineProj.appspot.com/myServlet
該文件已完全損壞。 如果我上傳一個文本文件,它在文件的開頭有一行廢話,最后有一行廢話,如:
------------------------------266cb0e18eba
Content-Disposition: form-data; name="file"; filename="blah.txt"
Content-Type: text/plain
hi how are you
------------------------------266cb0e18eba--
我如何告訴雲存儲我想將數據存儲為文件?
這對我有用
要上傳,請使用
curl -F file=@"picture.jpg" http://myAppEngineProj.appspot.com/myServlet
servlet看起來像
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();
}
}
}
參考文獻:楊奕森的答案和本帖
雖然另一篇文章的上傳大小限制<32 mb,但對我來說這不是問題。 此代碼還自動處理mime類型。
據我所知,Google雲端存儲或API沒有問題; 在從HttpServletRequest讀取內容時問題更早。
包含------ 266cb0e18eba的行實際上是MIME編碼的一部分,它標記了一個部分的開頭和結尾。
您可以通過以下兩種方法之一解決此問題。
更換:
$ curl -F file=@"picture.jpg" http://myAppEngineProj.appspot.com/myServlet
附:
$ curl -X POST -d @"picture.jpg" http://myAppEngineProj.appspot.com/myServlet
更換:
java.io.InputStream is = request.getInputStream();
附:
javax.servlet.http.Part filePart = request.getPart("file");
java.io.InputStream is = filePart.getInputStream()
這將在curl構造的多部分MIME消息中的正確部分上打開輸入流。
這在此處記錄:
http://docs.oracle.com/javaee/6/tutorial/doc/gmhba.html
選項B可能是更好的選擇,因為它可以用於表單和表單上傳。
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