I had written following code to copy database file from dropbox account to app database.But i want to copy only specific table from Dropbox to App database table.Is it possible.
protected Boolean doInBackground(Void... params) {
final File tempDir = context.getCacheDir();
File tempFile;
FileWriter fr;
try {
File data = Environment.getDataDirectory();
String currentDBPath = "//data//"+ "loginscreen.example.com.girviapp" +"//databases//"+DATABASE_NAME;
File currentDB = new File(data, currentDBPath);
FileInputStream fileInputStream = new FileInputStream(currentDB);
Entry existingentry= dropbox.metadata( path ,1000,null,true,null);
if (existingentry.contents.size() != 0)
{
for (Entry ent :existingentry.contents)
{
String name = ent.fileName();
if(name.equals(DATABASE_NAME))
{ FileOutputStream outputStream = new FileOutputStream(currentDB);
DropboxFileInfo info = dropbox.getFile(path + DATABASE_NAME, null, outputStream, null);
return true;
}
}
}
} catch (IOException e) {
e.printStackTrace();
} catch (DropboxException e) {
e.printStackTrace();
}
return false;
}
The answer here depends on exactly what you're looking to do.
If you want to be able to download only a specific table from the database file stored on Dropbox, in order to save bandwidth by not downloading all of the data, then no, this isn't possible. The unit of storage in the Dropbox API you're using is the file, and Dropbox doesn't know what the individual tables in your database file are, so it doesn't have a way for you to specify a particular table.
On the other hand, if you don't mind downloading the entire file from Dropbox, then yes, this is possible. Just download the file as you're doing, and then load it up as a database locally. Then query out just the data you want, that is, the desired table, and do what you need with it.
Related
try {
// db parameters
String url = "jdbc:sqlite: db_path.db";
// create a connection to the database
conn = DriverManager.getConnection(url);
System.out.println("Connection to SQLite has been established.");
} catch (SQLException e) {
System.out.println(e.getMessage());
}
When database is connected a duplicate file is created with same name and size 0Kb inside project folder
String query = "INSERT INTO Path VALUES (?)";
try {
PreparedStatement state = DB_Path.conn.prepareStatement(query);
state.setString(1,path);
} catch (SQLException e) {
System.out.println(e.getMessage());
}
Your connection does not have permissions to access the existing db file. So it creates a new (different) file
The problem is in url of database file i-e space between jdbc:sqlite: and db_path.db
The correct way is:
url = "jdbc:sqlite:db_path.db;
You can use absolute path too but keep in mind the above line of error, for locating some file in directory, it preferable to use backward slash b/w directories because it is used in windows path system and for java syntax it comes two times like this,
url = "jdbc:sqlite:C:\\Desktop\\db_path.db;
or you can use forward slash too,
url = "jdbc:sqlite:C:/Desktop/db_path.db;
Here's the warning that I am getting:
S3AbortableInputStream:Not all bytes were read from the S3ObjectInputStream, aborting HTTP connection. This is likely an error and may result in sub-optimal behavior. Request only the bytes you need via a ranged GET or drain the input stream after use.
I tried using try with resources but S3ObjectInputStream doesn't seem to close via this method.
try (S3Object s3object = s3Client.getObject(new GetObjectRequest(bucket, key));
S3ObjectInputStream s3ObjectInputStream = s3object.getObjectContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(s3ObjectInputStream, StandardCharsets.UTF_8));
){
//some code here blah blah blah
}
I also tried below code and explicitly closing but that doesn't work either:
S3Object s3object = s3Client.getObject(new GetObjectRequest(bucket, key));
S3ObjectInputStream s3ObjectInputStream = s3object.getObjectContent();
try (BufferedReader reader = new BufferedReader(new InputStreamReader(s3ObjectInputStream, StandardCharsets.UTF_8));
){
//some code here blah blah
s3ObjectInputStream.close();
s3object.close();
}
Any help would be appreciated.
PS: I am only reading two lines of the file from S3 and the file has more data.
Got the answer via other medium. Sharing it here:
The warning indicates that you called close() without reading the whole file. This is problematic because S3 is still trying to send the data and you're leaving the connection in a sad state.
There's two options here:
Read the rest of the data from the input stream so the connection can be reused.
Call s3ObjectInputStream.abort() to close the connection without reading the data. The connection won't be reused, so you take some performance hit with the next request to re-create the connection. This may be worth it if it's going to take a long time to read the rest of the file.
Following option #1 of Chirag Sejpal's answer I used the below statement to drain the S3AbortableInputStream to ensure the connection can be reused:
com.amazonaws.util.IOUtils.drainInputStream(s3ObjectInputStream);
I ran into the same problem and the following class helped me
#Data
#AllArgsConstructor
public class S3ObjectClosable implements Closeable {
private final S3Object s3Object;
#Override
public void close() throws IOException {
s3Object.getObjectContent().abort();
s3Object.close();
}
}
and now you can use without warning
try (final var s3ObjectClosable = new S3ObjectClosable(s3Client.getObject(bucket, key))) {
//same code
}
To add an example to Chirag Sejpal's answer (elaborating on option #1), the following can be used to read the rest of the data from the input stream before closing it:
S3Object s3object = s3Client.getObject(new GetObjectRequest(bucket, key));
try (S3ObjectInputStream s3ObjectInputStream = s3object.getObjectContent()) {
try {
// Read from stream as necessary
} catch (Exception e) {
// Handle exceptions as necessary
} finally {
while (s3ObjectInputStream != null && s3ObjectInputStream.read() != -1) {
// Read the rest of the stream
}
}
// The stream will be closed automatically by the try-with-resources statement
}
I ran into the same error.
As others have pointed out, the /tmp space in lambda is limited to 512 MB.
And if the lambda context is re-used for a new invocation, then the /tmp space is already half-full.
So, when reading the S3 objects and writing all the files to the /tmp directory (as I was doing),
I ran out of disk space somewhere in between.
Lambda exited with error, but NOT all bytes from the S3ObjectInputStream were read.
So, two things one need to keep in mind:
1) If the first execution causes the problem, be stingy with your /tmp space.
We have only 512 MB
2) If the second execution causes the problem, then this could be resolved by attacking the root problem.
Its not possible to delete the /tmp folder.
So, delete all the files in the /tmp folder after the execution is finished.
In java, here is what I did, which successfully resolved the problem.
public String handleRequest(Map < String, String > keyValuePairs, Context lambdaContext) {
try {
// All work here
} catch (Exception e) {
logger.error("Error {}", e.toString());
return "Error";
} finally {
deleteAllFilesInTmpDir();
}
}
private void deleteAllFilesInTmpDir() {
Path path = java.nio.file.Paths.get(File.separator, "tmp", File.separator);
try {
if (Files.exists(path)) {
deleteDir(path.toFile());
logger.info("Successfully cleaned up the tmp directory");
}
} catch (Exception ex) {
logger.error("Unable to clean up the tmp directory");
}
}
public void deleteDir(File dir) {
File[] files = dir.listFiles();
if (files != null) {
for (final File file: files) {
deleteDir(file);
}
}
dir.delete();
}
This is my solution. I'm using spring boot 2.4.3
Create an amazon s3 client
AmazonS3 amazonS3Client = AmazonS3ClientBuilder
.standard()
.withRegion("your-region")
.withCredentials(
new AWSStaticCredentialsProvider(
new BasicAWSCredentials("your-access-key", "your-secret-access-key")))
.build();
Create an amazon transfer client.
TransferManager transferManagerClient = TransferManagerBuilder.standard()
.withS3Client(amazonS3Client)
.build();
Create a temporary file in /tmp/{your-s3-key} so that we can put the file we download in this file.
File file = new File(System.getProperty("java.io.tmpdir"), "your-s3-key");
try {
file.createNewFile(); // Create temporary file
} catch (IOException e) {
e.printStackTrace();
}
file.mkdirs(); // Create the directory of the temporary file
Then, we download the file from s3 using transfer manager client
// Note that in this line the s3 file downloaded has been transferred in to the temporary file that we created
Download download = transferManagerClient.download(
new GetObjectRequest("your-s3-bucket-name", "your-s3-key"), file);
// This line blocks the thread until the download is finished
download.waitForCompletion();
Now that the s3 file has been successfully transferred into the temporary file that we created. We can get the InputStream of the temporary file.
InputStream input = new DataInputStream(new FileInputStream(file));
Because the temporary file is not needed anymore, we just delete it.
file.delete();
I would like to save my app data in Google Drive to share it between Devices of the User.
First if there is no file i create one in google Drive:
Drive.DriveApi.getAppFolder(driveApiClient)
.createFile(driveApiClient, changeSet, null)
In the callback i open the file:
driveFileResult.getDriveFile().open(driveApiClient, DriveFile.MODE_WRITE_ONLY, null)
And in that Callback i write to the File as described https://developers.google.com/drive/android/files#making_modifications:
DriveContents contents = driveContentsResult.getDriveContents();
try {
ParcelFileDescriptor parcelFileDescriptor = contents.getParcelFileDescriptor();
FileOutputStream fileOutputStream = new FileOutputStream(parcelFileDescriptor
.getFileDescriptor());
Writer writer = new OutputStreamWriter(fileOutputStream);
writer.write("hello world");
} catch (IOException e) {
e.printStackTrace();
}
contents.commit(driveApiClient, null, new ExecutionOptions.Builder().setConflictStrategy(ExecutionOptions.CONFLICT_STRATEGY_OVERWRITE_REMOTE).build())
In the status callback of the commit i get a success.
Next time i open the file the file is empty, and the size in the metadata is 0.
What am i doing wrong?
Just did a quick test. Definitely close the OutputStreamWriter - writer.close() before the commit; otherwise, you will get an empty file.
I have been trying to find the best way to do this I have thought of extracting the contents of the .jar then moving the files into the directory then putting it back as a jar. Im not sure is the best solution or how I will do it. I have looked at DotNetZip & SharpZipLib but don't know what one to use.
If anyone can give me a link to the code on how to do this it would be appreciated.
For DotNetZip you can find very simple VB.NET examples of both creating a zip archive and extracting a zip archive into a directory here. Just remember to save the compressed file with extension .jar .
For SharpZipLib there are somewhat more comprehensive examples of archive creation and extraction here.
If none of these libraries manage to extract the full JAR archive, you could also consider accessing a more full-fledged compression software such as 7-zip, either starting it as a separate process using Process.Start or using its COM interface to access the relevant methods in the 7za.dll. More information on COM usage can be found here.
I think you are working with Minecraft 1.3.1 no? If you are, there is a file contained in the zip called aux.class, which unfortunately is a reserved filename in windows. I've been trying to automate the process of modding, while manipulating the jar file myself, and have had little success. The only option I have yet to explore is find a way to extract the contents of the jar file to a temporary location, while watching for that exception. When it occurs, rename the file to a temp name, extract and move on. Then while recreating the zip file, give the file the original name in the archive. From my own experience, SharZipLib doesnt do what you need it do nicely, or at least I couldnt figure out how. I suggest using Ionic Zip (Dot Net Zip) instead, and trying the rename route on the offending files. In addition, I also posted a question about this. You can see how far I got at Extract zip entries to another Zip file
Edit - I tested out .net zip more (available from http://dotnetzip.codeplex.com/), and heres what you need. I imagine it will work with any zip file that contains reserved file names. I know its in C#, but hey cant do all the work for ya :P
public static void CopyToZip(string inArchive, string outArchive, string tempPath)
{
ZipFile inZip = null;
ZipFile outZip = null;
try
{
inZip = new ZipFile(inArchive);
outZip = new ZipFile(outArchive);
List<string> tempNames = new List<string>();
List<string> originalNames = new List<string>();
int I = 0;
foreach (ZipEntry entry in inZip)
{
if (!entry.IsDirectory)
{
string tempName = Path.Combine(tempPath, "tmp.tmp");
string oldName = entry.FileName;
byte[] buffer = new byte[4026];
Stream inStream = null;
FileStream stream = null;
try
{
inStream = entry.OpenReader();
stream = new FileStream(tempName, FileMode.Create, FileAccess.ReadWrite);
int size = 0;
while ((size = inStream.Read(buffer, 0, buffer.Length)) > 0)
{
stream.Write(buffer, 0, size);
}
inStream.Close();
stream.Flush();
stream.Close();
inStream = new FileStream(tempName, FileMode.Open, FileAccess.Read);
outZip.AddEntry(oldName, inStream);
outZip.Save();
}
catch (Exception exe)
{
throw exe;
}
finally
{
try { inStream.Close(); }
catch (Exception ignore) { }
try { stream.Close(); }
catch (Exception ignore) { }
}
}
}
}
catch (Exception e)
{
throw e;
}
}
I am building REST application. I want to upload a file and I want to save it for example in /WEB-INF/resource/uploads
How can I get path to this directory ? My Controller looks like this
#RequestMapping(value = "/admin/house/update", method = RequestMethod.POST)
public String updateHouse(House house, #RequestParam("file") MultipartFile file, Model model) {
try {
String fileName = null;
InputStream inputStream = null;
OutputStream outputStream = null;
if (file.getSize() > 0) {
inputStream = file.getInputStream();
fileName = "D:/" + file.getOriginalFilename();
outputStream = new FileOutputStream(fileName);
int readBytes = 0;
byte[] buffer = new byte[10000];
while ((readBytes = inputStream.read(buffer, 0, 10000)) != -1) {
outputStream.write(buffer, 0, readBytes);
}
outputStream.close();
inputStream.close();
}
} catch(Exception ex) {
ex.printStackTrace();
}
model.addAttribute("step", 3);
this.houseDao.update(house);
return "houseAdmin";
}
Second question...what is the best place to upload user files ?
/WEB-INF is a bad place to try to store file uploads. There's no guarantee that this is an actual directory on the disk, and even if it is, the appserver may forbid write access to it.
Where you should store your files depends on what you want to do with them, and what operating system you're running on. Just pick somewhere outside of the webapp itself, is my advice. Perhaps create a dedicated directory
Also, the process of transferring the MultipartFile to another location is much simpler than you're making it out to be:
#RequestMapping(value = "/admin/house/update", method = RequestMethod.POST)
public String updateHouse(House house, #RequestParam("file") MultipartFile srcFile, Model model) throws IOException {
File destFile = new File("/path/to/the/target/file");
srcFile.transferTo(destFile); // easy!
model.addAttribute("step", 3);
this.houseDao.update(house);
return "houseAdmin";
}
You shouldn't store files in /WEB-INF/resource/uploads. This directory is either inside your WAR (if packaged) or exploded somewhere inside servlet container. The first destination is read-only and the latter should not be used for user files.
There are usually two places considered when storing uploaded files:
Some dedicated folder. Make sure users cannot access this directory directly (e.g. anonymous FTP folder). Note that once your application runs on more than one machine you won't have access to this folder. So consider some form of network synchronization or a shared network drive.
Database. This is controversial since binary files tend to occupy a lot of space. But this approach is a bit simpler when distributing your application.