为什么Google Cloud使用Google app engine Java存储的文件大小小于上传的文件大小
将文件上载到Google云存储时，存储文件的大小与原始上载文件的大小不同。存储的文件比原始大小小得多。我的上传servlet如下所示为什么Google Cloud使用Google app engine Java存储的文件大小小于上传的文件大小,java,google-app-engine,google-cloud-storage,Java,Google App Engine,Google Cloud Storage,将文件上载到Google云存储时，存储文件的大小与原始上载文件的大小不同。存储的文件比原始大小小得多。我的上传servlet如下所示 public class UploadServlet extends HttpServlet{ private static final long serialVersionUID = 1L; private StorageService storage = new StorageService(); private static int
public class UploadServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
private StorageService storage = new StorageService();
private static int BUFFER_SIZE =1024 * 1024* 10;
DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
@Override
public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
ServletFileUpload upload = new ServletFileUpload();
boolean isMultipart = ServletFileUpload.isMultipartContent(req);
if (!isMultipart) {
resp.getWriter().println("File cannot be uploaded !");
return;
}
FileItemIterator iter;
try {
iter = upload.getItemIterator(req);
while (iter.hasNext()) {
FileItemStream item = iter.next();
String fileName = item.getName();
String fieldName = item.getFieldName();
String mime = item.getContentType();
if (fieldName.equals("file")) { // the name of input field in html
InputStream is1 = item.openStream();
try {
FileService fileService = FileServiceFactory.getFileService();
AppEngineFile file = fileService.createNewBlobFile(mime, fileName);
boolean lock = true;
FileWriteChannel writeChannel = fileService.openWriteChannel(file, lock);
byte[] b1 = new byte[BUFFER_SIZE];
int readBytes1;
while ((readBytes1 = is1.read(b1)) != -1) {
writeChannel.write(ByteBuffer.wrap(b1, 0, readBytes1));
storage.init(fileName, mime);
storage.storeFile(b1, readBytes1);
}
writeChannel.closeFinally();
String blobKey = fileService.getBlobKey(file).getKeyString();
Entity input = new Entity("Input");
input.setProperty("Input File", blobKey);
datastore.put(input);
is1.close();
storage.destroy();
} catch (Exception e) {
e.printStackTrace(resp.getWriter());
}
}
}
} catch (FileUploadException e) {
// log error here
}
}
}
public class StorageService {
public static final String BUCKET_NAME = "MyBucket";
private FileWriteChannel writeChannel = null;
FileService fileService = FileServiceFactory.getFileService();
private BufferedOutputStream bos = null;
private static final Logger log = Logger.getLogger(StorageService.class.getName());
private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
public void init(String fileName, String mime) throws Exception {
System.out.println("Storage service:init() method: file name:"+fileName+" and mime:"+mime);
log.info("Storage service:init() method: file name:"+fileName+" and mime:"+mime);
GSFileOptionsBuilder builder = new GSFileOptionsBuilder()
.setAcl("public_read")
.setBucket(BUCKET_NAME)
.setKey(fileName)
.setMimeType(mime);
AppEngineFile writableFile = fileService.createNewGSFile(builder.build());
boolean lock = true;
writeChannel = fileService.openWriteChannel(writableFile, lock);
bos = new BufferedOutputStream(Channels.newOutputStream(writeChannel));
}
public void storeFile(byte[] b, int readSize) throws Exception {
bos.write(b,0,readSize);
System.out.println(readSize);
bos.flush();
}
public void destroy() throws Exception {
log.info("Storage service: destroy() method");
bos.close();
writeChannel.closeFinally();
}
public BlobKey getBlobkey (String filename) {
BlobKey bk = blobstoreService.createGsBlobKey("/gs/MyBucket/"+filename);
return bk;
}
}
public class UploadServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
private StorageService storage = new StorageService();
private static int BUFFER_SIZE =1024 * 1024* 10;
DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
@Override
public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
ServletFileUpload upload = new ServletFileUpload();
boolean isMultipart = ServletFileUpload.isMultipartContent(req);
if (!isMultipart) {
resp.getWriter().println("File cannot be uploaded !");
return;
}
FileItemIterator iter;
try {
iter = upload.getItemIterator(req);
while (iter.hasNext()) {
FileItemStream item = iter.next();
String fileName = item.getName();
String fieldName = item.getFieldName();
String mime = item.getContentType();
if (fieldName.equals("file")) { // the name of input field in html
InputStream is1 = item.openStream();
try {
FileService fileService = FileServiceFactory.getFileService();
AppEngineFile file = fileService.createNewBlobFile(mime, fileName);
boolean lock = true;
FileWriteChannel writeChannel = fileService.openWriteChannel(file, lock);
byte[] b1 = new byte[BUFFER_SIZE];
int readBytes1;
while ((readBytes1 = is1.read(b1)) != -1) {
writeChannel.write(ByteBuffer.wrap(b1, 0, readBytes1));
storage.init(fileName, mime);
storage.storeFile(b1, readBytes1);
}
writeChannel.closeFinally();
String blobKey = fileService.getBlobKey(file).getKeyString();
Entity input = new Entity("Input");
input.setProperty("Input File", blobKey);
datastore.put(input);
is1.close();
storage.destroy();
} catch (Exception e) {
e.printStackTrace(resp.getWriter());
}
}
}
} catch (FileUploadException e) {
// log error here
}
}
}
public class StorageService {
public static final String BUCKET_NAME = "MyBucket";
private FileWriteChannel writeChannel = null;
FileService fileService = FileServiceFactory.getFileService();
private BufferedOutputStream bos = null;
private static final Logger log = Logger.getLogger(StorageService.class.getName());
private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
public void init(String fileName, String mime) throws Exception {
System.out.println("Storage service:init() method: file name:"+fileName+" and mime:"+mime);
log.info("Storage service:init() method: file name:"+fileName+" and mime:"+mime);
GSFileOptionsBuilder builder = new GSFileOptionsBuilder()
.setAcl("public_read")
.setBucket(BUCKET_NAME)
.setKey(fileName)
.setMimeType(mime);
AppEngineFile writableFile = fileService.createNewGSFile(builder.build());
boolean lock = true;
writeChannel = fileService.openWriteChannel(writableFile, lock);
bos = new BufferedOutputStream(Channels.newOutputStream(writeChannel));
}
public void storeFile(byte[] b, int readSize) throws Exception {
bos.write(b,0,readSize);
System.out.println(readSize);
bos.flush();
}
public void destroy() throws Exception {
log.info("Storage service: destroy() method");
bos.close();
writeChannel.closeFinally();
}
public BlobKey getBlobkey (String filename) {
BlobKey bk = blobstoreService.createGsBlobKey("/gs/MyBucket/"+filename);
return bk;
}
}
非常感谢您的帮助。在UploadServlet类中，您调用storage.init。。。每个文件多次，始终重新创建文件。这不应该发生：
while ((readBytes1 = is1.read(b1)) != -1) {
writeChannel.write(ByteBuffer.wrap(b1, 0, readBytes1));
storage.init(fileName, mime); // <- HERE
storage.storeFile(b1, readBytes1);
}
您需要将init语句移出循环，放在它前面。在UploadServlet类中，调用storage.init。。。每个文件多次，始终重新创建文件。这不应该发生：
while ((readBytes1 = is1.read(b1)) != -1) {
writeChannel.write(ByteBuffer.wrap(b1, 0, readBytes1));
storage.init(fileName, mime); // <- HERE
storage.storeFile(b1, readBytes1);
}
您需要将init语句移出循环，放在前面。我在理解代码时遇到问题。在我看来，您似乎使用两种方式来编写文件。一个是通过存储服务，另一个是通过文件服务。你指的是哪一个？在存储服务中，当我在谷歌云中存储供你参考时，这两行出现了这个问题storage.initfileName，mime；storage.storeFileb1，readBytes1；我理解你的代码有问题。在我看来，您似乎使用两种方式来编写文件。一个是通过存储服务，另一个是通过文件服务。你指的是哪一个？在存储服务中，当我在谷歌云中存储供你参考时，这两行出现了这个问题storage.initfileName，mime；storage.storeFileb1，readBytes1；非常感谢你，丹尼尔。它解决了问题。。向你致敬：你能告诉我如何在上传servlet的文件服务中获得上述问题的文件大小吗谢谢你，daniel，它解决了这个问题。。向你致敬：你能告诉我如何在上面问题的上传servlet中获得文件服务中的文件大小吗