Writing to a file inside of a jar - java

I am having a problem writing to a .xml file inside of my jar. When I use the following code inside of my Netbeans IDE, no error occurs and it writes to the file just fine.
public void saveSettings(){
Properties prop = new Properties();
FileOutputStream out;
try {
File file = new File(Duct.class.getResource("/Settings.xml").toURI());
out = new FileOutputStream(file);
prop.setProperty("LAST_FILE", getLastFile());
try {
prop.storeToXML(out,null);
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e.toString());
}
try {
out.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e.toString());
}
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e.toString());
}
}
However, when I execute the jar I get an error saying:
IllegalArguementException: uri is not hierachal
Does anyone have an idea of why it's working when i run it in Netbeans, but not working when i execute the jar. Also does anyone have a solution to the problem?

The default class loader expects the classpath to be static (so it can cache heavily), so this approach will not work.
You can put Settings.xml in the file system if you can get a suitable location to put it. This is most likely vendor and platform specific, but can be done.

Add the location of the Settings.xml to the classpath.

I was also struggling with this exception. But finally found out the solution.
When you use .toURI() it returns some thing like
D:/folderName/folderName/Settings.xml
and hence you get the exception "URI is not hierarchical"
To avoid this call the method getPath() on the URI returned, which returns something like
/D:/folderName/folderName/Settings.xml
which is now hierarchical.
In your case, the 5th line in your code should be
File file = new File(Duct.class.getResource("/Settings.xml").toURI().getPath());

Related

Why do I get NullPointerException when trying to access resource file?

I want to make so a file in the program is packaged in the jar file because it is needed in my program. It is the firebase credentials file. I read that I need to add it to the resource folder but now I cannot access it because I get NullPointerException. I think the path is valid and everything seems okay but I get null every time. Here is the code:
ClassLoader classLoader = EmailSender.class.getClassLoader();
File file = new File(Objects.requireNonNull(classLoader.getResource("/parkingsystem-cf164-firebase-adminsdk-5jjuk-2be72bfcce.json")).getFile());
And here is the code structure:
code structure
If there is another method to add file to jar I am open to hear it, it is just what I found on the Internet but it does not work for me. Any help is appreciated!
Edit: So apparently it works when the / is removed but then I need to convert it to FileInputStream and there I get FileNotFoundExcpetion. The rest of the code:
FileInputStream serviceAccount = null;
try {
serviceAccount = new FileInputStream(file);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
FirebaseOptions options = null;
try {
options = new FirebaseOptions.Builder()
.setCredentials(GoogleCredentials.fromStream(serviceAccount))
.build();
} catch (IOException e) {
e.printStackTrace();
}

how to check if output folder is created in java?

I am coming to an issue where I am trying to check if output folder is there and if not create one in my code below. So, I tried doing that way as shown in my code but I dont know if its the proper a way of doing it? can you please advise. thanks for the help.
here is my code:
String outputFolder2 = Printer.getOutputFolder();
File outFileTwo = new File(outputFolder2);
if (!outFileTwo.exists()) {
if (!outFileTwo.mkdir()) {
System.out.println("Failed to make directory for: " + outputFolder2);
}
}
To check if the directory exists:
Files.isDirectory(Paths.get("/the/path"))
To create dir if not exists:
Files.createDirectories(Paths.get("/the/path"))
Simply use
dirPathFileObj.mkdir();
From java.io.File;
If the method detects that no such directory exists, it will automatically create one. Otherwise, it will simply do nothing in terms of File creation.
It's recommended to use the nio package for new code that interacts with files -- it's faster, and easier to code for. Here's how I would write that code, in the form of a junit test that I ran to verify it:
#Test
public void testSomething() {
Path dirPath = Paths.get("C:/I/do/not/exist");
Path filePath = dirPath.resolve("newFile.txt");
try {
assertFalse(Files.exists(dirPath));
dirPath = createDirectories(dirPath);
filePath = Files.createFile(filePath);
assertTrue(Files.exists(filePath));
} catch (IOException iox) {
iox.printStackTrace();
} finally {
try {
Files.deleteIfExists(filePath);
Files.deleteIfExists(dirPath);
} catch (Exception e) {
e.printStackTrace();
}
}
}
This will create C:\I\do\not\exist\newFile.txt, then delete C:\I\do\not\exist, (leaving C:\I\do\not\). For production code, you'd want to remove the asserts and fill in those catch clauses

Java Path exception

So, I used java.io.File for basically everything before.
But now, when switching to java.nio.Path, I'm experiencing a few problems...
What I use it for is basically loading/saving files, on my program startup and shutdown.
I use it in multiple places but I'll type an example:
Objects.requireNonNull(directory, "directory");
if (this.myObjectMap.isEmpty()) {
return;
}
Files.list(directory).forEach(file -> {
try {
Files.deleteIfExists(file);
} catch (IOException exception) {
exception.printStackTrace();
}
});
Files.createDirectories(directory);
for (Object object : this.myObjectMap.values()) {
Path destination = directory.resolve(object.toString() + ".json");
Files.deleteIfExists(destination);
Files.createFile(destination);
JsonObject properties = new JsonObject();
JSONFileHandler.save(destination, properties);
}
My problem is that everytime I do something similar to this, it throws a NoSuchFileException exception before even using the Path... But I don't know what I'm doing wrong, since I check if it exists after creating the Path.
Update
The exception stacktrace is the following:
java.nio.file.NoSuchFileException: **the directory**
at sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:79)
at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:97)
at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:102)
at sun.nio.fs.WindowsDirectoryStream.<init>(WindowsDirectoryStream.java:86)
at sun.nio.fs.WindowsFileSystemProvider.newDirectoryStream(WindowsFileSystemProvider.java:518)
at java.nio.file.Files.newDirectoryStream(Files.java:457)
at java.nio.file.Files.list(Files.java:3451)
Here's the javadoc for Path, this is what it says:
An object that may be used to locate a file in a file system. It will
typically represent a system dependent file path.
So, a Path just represents a Path, it's not a pointer to an existing file or directory and hence, it may or may not exist.
In our example, we need to check whether the Path exists, before calling Files.list and that would make sure we are iterating through valid path, e.g.:
Path directory = Paths.get("some directory");
Objects.requireNonNull(directory, "directory");
if(Files.exists(directory)){
Files.list(directory).forEach(file -> {
try {
System.out.println(file);
} catch (Exception exception) {
exception.printStackTrace();
}
});
}

Resources not being released

We have a legacy system that has a admim module that allows users to upload jar files. After the upload, the jar file is validated and if not compliant to internal rules, it is deleted.
The problem is that windows is throwing an exception telling that the file "is already being used by another process." (when I call Files.delete(tmpJar);). I'm not able to identify why the file is open. Seems to me that I have closed everything.
First, we are using primefaces (4.0) to upload the file. Primefaces relies on commons-fileupload (1.3.1). It call the following method:
public void handleFileUpload(FileUploadEvent event) {
Path tmpJar = null;
try {
tmpJar = Files.createFile(Paths.get(event.getFile().getFileName()));
Files.write(tmpJar, event.getFile().getContents());
} catch (IOException e) {
LOGGER.error(e.getMessage(), e);
}
if (tmpJar != null) {
try {
this.validateJar(tmpJar.toString());
Files.delete(tmpJar);
} catch (IOException e) {
LOGGER.error(e.getMessage(), e);
}
}
}
Before NIO Files.write, I was using "standard" java IO classes. The problem isn't related to the above code, because if I comment the call to validateJar, Files.delete(tmpJar) is executed without problems and the file is removed. So, the problem is related with the code below, but I can't find where...
Job is an internal class, basically a simple POJO. "jobAnnotation" is a custom annotation to identify Jobs. I have shortened the code, but the essencial parts are preserved.
private List<Job> validateJar(final String jarPath) throws IOException {
List<Job> jobs = new ArrayList<Job>();
try (JarFile jarFile = new JarFile(jarPath)) {
URL[] jars = { new URL("file:" + jarPath) };
ClassLoader jobClassLoader = URLClassLoader.newInstance(jars, this.getClass().getClassLoader());
Enumeration<JarEntry> jarEntries = jarFile.entries();
while (jarEntries.hasMoreElements()) {
JarEntry jarEntry = jarEntries.nextElement();
String className = jarEntry.getName();
Class<?> classToLoad;
try {
classToLoad = Class.forName(className, true, jobClassLoader);
} catch (Exception e1) {
LOGGER.error(e1.getMessage(), e1);
continue;
}
if (classToLoad.isAnnotationPresent(jobAnnotation)) {
String vlr = null;
try {
Class<?> jobClass = (Class<?>) Class.forName(classToLoad.getCanonicalName(), true, jobClassLoader);
Annotation annotation = jobClass.getAnnotation(jobAnnotation);
Method method = annotation.getClass().getMethod("getValue");
vlr = ((String) method.invoke(annotation, new Object[0]));
} catch (Exception e1) {
LOGGER.error(e1.getMessage(), e1);
}
Job job = new Job();
job.setEnabled(true);
job.setJarfile(jarPath);
job.setClassName(classToLoad.getName());
Parameter parameter = new Parameter();
parameter.setRequired(true);
parameter.setName("name");
parameter.setValue(vlr);
job.addParameter(parameter);
jobs.add(job);
}
}
} catch (IOException e) {
throw e;
}
return jobs;
}
Before using try-with-resources, I was using regular try-catch-finally to close the JarFile, thats the only thing that has a explicit close method. Probably is the classloading that is holding the file open, but I don't know how to close it.
I did some searches, and I found that I can't unload classes (Unloading classes in java?).
So, the problem is, how do I release it? Or how can I remove the file?
BTW, I'm using java 1.7.0_71, jboss 7.1.1, windows 7 (64).
The URLClassLoader class already has a close() method. The close() method will close any Jar file that are opened with the URLClassLoader. This should prevent the "file already in use" exception.
File is already being used by another process. says that it could be not your fault, maybe just another application is used that file. You can check this question to find a process which is used your file.
Some Virus scanner software take a long time in checking JARs. Try to disable the Virusscanner. Other candidates can be the Windows indexer process, or the explorer.exe itself. When you don't find any reason for the file lock, try a delay between the validation and the deletion. Maybe you need a loop with multiple tries.

Accessing a PDF in Jar

I'm creating a Java application using Netbeans. From the 'Help' Menu item, I'm required to open a PDF file. When I run the application via Netbeans, the document opens, but on opening via the jar file, it isn't opening. Is there anything that can be done?
m_aboutItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Runtime rt = Runtime.getRuntime();
URL link2=getClass().getResource("/newpkg/Documentation.pdf");
String link=link2.toString();
link=link.substring(6);
System.out.println(link);
System.out.println(link2);
String link3="E:/new/build/classes/newpkg/Documentation.pdf";
try {
Process proc = rt.exec("rundll32.exe url.dll,FileProtocolHandler " + link3);
} catch (IOException ex) {
Logger.getLogger(Menubar1.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
The two outputs are as follows:
E:/new/build/classes/newpkg/Documentation.pdf
file:/E:/new/build/classes/newpkg/Documentation.pdf
Consider the above code snippet. On printing 'link',we can see that it is exactly same as the hard coded 'link3'. On using the hard coded 'link3' , the PDF file gets opened from jar application. But when we use link, though it is exactly same as 'link3', the PDF doesn't open.
This is most likely related to the incorrect PDF resource loading. In the IDE you have the PDF file either as part of the project structure or with a directly specified relative path. When a packaged application is running it does not see the resource.
EDIT:
Your code reveals the problem as I have described. The following method could be used to properly identify resource path.
public static URL getURL(final String pathAndFileName) {
return Thread.currentThread().getContextClassLoader().getResource(pathAndFileName);
}
Pls refer to this question, which might provide additional information.
Try out this:
m_aboutItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (Desktop.isDesktopSupported()) {
Desktop desktop = Desktop.getDesktop();
URL link2=Menubar1.class.getResource("/newpkg/Documentation.pdf");
String link=link2.toString();
link=link.substring(6);
System.out.println(link);
File file=new File(link);
System.out.println(file);
try {
desktop.open(file);
} catch (IOException ex) {
Logger.getLogger(Menubar1.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
});

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