I am using this code and it keeps only getting to the output file line and throws the exception then. Can anyone see what the issue might be with this line?
try{
Log.e("Trying","try");
// Local database
InputStream input = new FileInputStream("/data/data/package/databases/database");
Log.e("Input","in");
// create directory for backup
// Path to the external backup
OutputStream output = new FileOutputStream("/sdcard/android/package/databases/mydatabase.db");
Log.e("Output","out");
// transfer bytes from the Input File to the Output File
byte[] buffer = new byte[1024];
Log.e("Buffer","Buff");
int length;
while ((length = input.read(buffer))>0) {
output.write(buffer, 0, length);
}
Log.e("After While","try");
output.flush();
output.close();
input.close();
} catch (IOException e) {
throw new Error("Copying Failed");
}
I doubt this is the cause of your problem, but the following two lines:
OutputStream output = new FileOutputStream("/sdcard/android/package/databases/mydatabase.db");
InputStream input = new FileInputStream("/data/data/package/databases/database");
should be turned into:
File sdcard = Environment.getExternalStorageDirectory();
File outputFile = new File(sdcard, "android/package/databases/mydatabase.
File data = Environment.getDataDirectory();
File inputFile = new File(data, "data/package/databases/database");
InputStream input = new FileInputStream(inputFile);
OutputStream output = new FileOutputStream(outputFile);
This is because the sdcard and data directories may be in different places on different phones. And often, you need to do /mnt/sdcard/ to actually reference the sd card, but the best way is still to use Files and use Environment as I showed above.
You would of course need to put it all into a try block as you already have, and then within the catch, you will need to put e.printStackTrace(); and then if an error is thrown, you can look at the errors from the logcat to determine where your code fails instead of using a log every couple of lines.
And, in your Manifest you have to have the following permission:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
Related
this is my directory structure
Inside the server I have the following code for saving a file that gets sent from the client
fileName = reader.readLine();
DataInputStream dis = null;
try {
dis = new DataInputStream(csocket.getInputStream());
FileOutputStream fos = new FileOutputStream(fileName);
buffer = new byte[4096];
int fileSize = 15123;
int read = 0;
int totalRead = 0;
int remaining = fileSize;
while((read = dis.read(buffer, 0, Math.min(buffer.length, remaining))) > 0) {
totalRead += read;
remaining -= read;
fos.write(buffer, 0, read);
}
fos.close();
dis.close();
} catch (IOException e) {
}
break;
I'm wondering how I would go about saving the file within the xml folder? I've tried using getClass().getResource and such but nothing seems to work.
fileName is just a simple string containing the name of the file, not a path or anything.
I get the correct path using this code:
File targetDir = new File(getClass().getResource("xml").getPath());
File targetFile = new File(targetDir, fileName);
targetFile.createNewFile();
System.out.println(targetFile.getAbsolutePath());
dis = new DataInputStream(csocket.getInputStream());
FileOutputStream fos = new FileOutputStream(targetFile.getAbsolutePath(), false);
But it still won't save it there...
The best way is to receive explicitly the target path for storing files, either through a .properties file or a command-line argument. In this way, you make your program flexible to be installed and adapted in different environments.
But if you wish your program to assume the target directory automatically, the best option is to set a relative path before creating the FileOutputStream, as long as you start your program always from the same path:
File targetDir=new File("xml");
File targetFile=new File(targetDir, fileName);
FileOutputStream fos = new FileOutputStream(targetFile);
This will work assuming the program is started from server as current directory.
Update
Other minor suggestions about your program:
Never base the exit condition of the loop on a hard-coded file size, because it is not possible to know it a priori. Instead, check explicitly if the value returned by read is less than 0 => that means End Of File reached.
Consequently, do not bother to calculate the exact amount of data to get through a call to read. Just enter the buffer size, because you are setting a maximum data size.
Never let exceptions catched without a proper treatment: If you know how to make your program recover, enter a proper code into the catch block. Otherwise, you'd better not catch them: Declare them in the throws clause and let them be propagated to the caller.
Always create stream resources through the try-with-resources instruction, to ensure they got closed at the end:
try (FileOutputStream fos = new FileOutputStream(...))
{
// ... use fos...
}
Save unnecessary instructions: If you don't care about if the file already exists on the filesystem or not, don't call createNewFile. But if you care, check the returned value and bifurcate consequently.
I try to create file and it does created but not at ProjectName\src\com\company\xml but in ProjectName\out\production\ProjectName\com\company\xml
my code:
File targetDir = new File(this.getClass().getResource("xml").getPath());
// get the parent of the file
String parentPath = targetDir.getParent( );
String fileName="xml/name.txt";
//do something
File targetFile = new File(parentPath, fileName);
targetFile.createNewFile();
Just pay attention that after compilation you will try to save it into a jar file and it a complicated thing to do.
usually you need to save file into file outside from your jar(separate in the root) like this:
I have some word documents and excel sheets which has some images along with the file text content. I want to create a copy of that file and keep it at a specific location. I tried the following method which is creating file at specified location but the file is corrupted and cannot be read.
InputStream document = Thread.currentThread().getContextClassLoader().getResourceAsStream("upgradeworkbench/Resources/Upgrade_TD_Template.docx");
try {
OutputStream outStream = null;
Stage stage = new Stage();
stage.setTitle("Save");
byte[] buffer= new byte[document.available()];
document.read(buffer);
FileChooser fileChooser = new FileChooser();
fileChooser.setInitialFileName(initialFileName);
if (flag) {
fileChooser.getExtensionFilters().addAll(new FileChooser.ExtensionFilter("Microsoft Excel Worksheet", "*.xls"));
} else {
fileChooser.getExtensionFilters().addAll(new FileChooser.ExtensionFilter("Microsoft Word Document", "*.docx"));
}
fileChooser.setTitle("Save File");
File file = fileChooser.showSaveDialog(stage);
if (file != null) {
outStream = new FileOutputStream(file);
outStream.write(buffer);
// IOUtils.copy(document, outStream);
}
} catch (IOException ex) {
System.out.println(ex.getMessage());
}
Can anyone suggest me any different ways to get the proper file.
PS: I am reading the file using InputStream because it is inside the project jar.
PPS: I also tried Files.copy() but it didnt work.
I suggest you never trust on InputStream.available to know the real size of the input, because it just returns the number of bytes ready to be immediately read from the buffer. It might return a small number, but doesn't mean the file is small, but that the buffer is temporarily half-full.
The right algorithm to read an InputStream fully and write it over an OutputStream is this:
int n;
byte[] buffer=new byte[4096];
do
{
n=input.read(buffer);
if (n>0)
{
output.write(buffer, 0, n);
}
}
while (n>=0);
You can use the Files.copy() methods.
Copies all bytes from an input stream to a file. On return, the input stream will be at end of stream.
Use:
Files.copy(document, file.toPath(), StandardCopyOption.REPLACE_EXISTING);
As the class says, the second argument is a Path, not a File.
Generally, since this is 2015, use Path and drop File; if an API still uses File, make it so that it uses it at the last possible moment and use Path all the way.
I am trying to Compare last modified date of two excel files and replace the old file with new file.
In Scenario : When there is no file in the first place, so the code copies the file to that location and later reads it.
Issue is : It throws a FileNotFound exception when the excel file is not present on the server,even after writing the file to the
server(via code),but the file is not seen on the server. It works on
my machine(windows),but fails when deployed on server.
Again, it works like charm when the file is present on the server,while the old is being replaced by the new file.
Can you please help and explain on why its failing in the above scenario,and only on server ?
if(row.getValue("fileType").toString().equals("xlsx")&&checkindatefolder.after(localdate))
{
messagelist.add("we are going to get the replace file in the server");
InputStream inp=folder.getFile();
ZipInputStream izs = new ZipInputStream(inp);
ZipEntry e = null;
while ((e = izs.getNextEntry()) != null) {
System.out.println("e.isDirectory(): "+e.isDirectory());
if (!e.isDirectory()) {
filename=e.getName();
System.out.println("filename: "+filename);
FileOutputStream os=new FileOutputStream("path"+e.getName());
byte[] buffer = new byte[4096];
int read=0;
System.out.println("writing to file");
while ((read=izs.read(buffer))> 0) {
System.out.println("1111");
os.write(buffer,0,read);
}
System.out.println("writing to file complete");
inp.close();
os.flush();
os.close();
}
}
Do all parts of the path exist?
So in your example:
/u01/app/webapps/out/pj/Create.xlsx
Do all subdirectories exist?
/u01/app/webapps/out/pj
If not, than trying to write there might fail with a FileNotFoundException.
You should create the directories with Files.creatDirectories(Path) first.
Hi I am trying to write some code in my program so I can grab a file from the internet but it seems that is not working. Can someone give me some advice please ? Here is my code. In this case I try to download an mp3 file from the last.fm website, my code runs perfectly fine but when I open my downloads directory the file is not there. Any idea ?
public class download {
public static void main(String[] args) throws IOException {
String fileName = "Death Grips - Get Got.mp3";
URL link = new URL("http://www.last.fm/music/+free-music-downloads");
InputStream in = new BufferedInputStream(link.openStream());
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
int n = 0;
while (-1!=(n=in.read(buf)))
{
out.write(buf, 0, n);
}
out.close();
in.close();
byte[] response = out.toByteArray();
FileOutputStream fos = new FileOutputStream(fileName);
fos.write(response);
fos.close();
System.out.println("Finished");
}
}
Every executing program has a current working directory. Often times, it is the directory where the executable lives (if it was launched in a "normal" way).
Since you didn't specify a path (in fileName), the file will be saved with that name in the current working directory.
If you want the file to be saved in your downloads directory, specify the full path. E.g.
String fileName = "C:\\Users\\YOUR_USERNAME\\Downloads\\Death Grips - Get Got.mp3";
Note how I've escaped the backslashes. Also note that there are methods for joining paths in Java. There is a way to get the current working directory in Java.
I need to create Bzip2 archive.
A downloaded bzip2 library from 'Apache ant'.
I use class CBZip2OutputStream:
String s = .....
CBZip2OutputStream os = new CBZip2OutputStream(fos);
os.write(s.getBytes(Charset.forName("UTF-8")));
os.flush();
os.close();
(I didn't find any example how to use it, so I decided to use it in this way)
But it creates a corrupted archive on the disk.
You have to add BZip2 header (two bytes: 'B','Z') before writing the content:
//Write 'BZ' before compressing the stream
fos.write("BZ".getBytes());
//Write to compressed stream as usual
CBZip2OutputStream os = new CBZip2OutputStream(fos);
... the rest ...
Then, for instance, you can extract contents of your bzipped file with cat compressed.bz2 | bunzip2 > uncompressed.txt on a *nix system.
I have not found an example but in the end I understood how to use CBZip2OutputStream so here is one :
public void createBZipFile() throws IOException{
// file to zip
File file = new File("plane.jpg");
// fichier compresse
File fileZiped= new File("plane.bz2");
// Outputstream for fileZiped
FileOutputStream fileOutputStream = new FileOutputStream(fileZiped);
fileOutputStream.write("BZ".getBytes());
// we getting the data in a byte array
byte[] fileData = getArrayByteFromFile(file);
CBZip2OutputStream bzip = null;
try{
bzip = new CBZip2OutputStream(fileOutputStream );
bzip.write(fileData, 0, fileData.length);
bzip.flush() ;
bzip.close();
}catch (IOException ex) {
ex.printStackTrace();
}
fos.close();
}