When trying to load the file in Eclipse the file loads just fine, however when I package the project into a .JAR file using jar-splice it seems that the application can no longer locate its resource files.
Here's the error thrown when the application is run
And here is the method that loads files:
public static File loadFile(String path) throws FileNotFoundException
{
InputStream stream;
stream = FileUtil.class.getClassLoader().getResourceAsStream(path);
System.out.println("Stream = " + stream); //Debug purposes
File file = new File(FileUtil.class.getClassLoader().getResource(path).getFile());
if (!file.exists())
{
System.err.println("Path: " + FileUtil.class.getClassLoader().getResource(path).getPath()); //Also debug purposes
throw new FileNotFoundException();
}
return file;
}
Using those two System.out.printlns it's clear that the application can't find the file based on that path, but if you look at the picture that path is exactly where the file it's looking for is located. I am so confused as this has never happened before, and the path it's saying it can't find the file at is exactly where it is. Any ideas anyone?
Here is the method that files
Here is the method that neither does nor can load resources as Files. It is impossible. Resources are not files and do not live in the file system. You must redesign it to return either a URL or an InputStream, and as you can get both directly from a Class or ClassLoader you don't actually need the method at all.
Related
My code executes as expected in Eclipse, but when I attempted to export it to an executable jar, it stopped loading resources. I looked at a lot of examples here, but couldn't seem to figure out what I had done wrong. I reviewed the jar contents and the resource files are all there. The hierarchy in the jar is:
/src/code
/resources files
Within Eclipse project the hierarchy is
/src/classes
/resources/resource files
At program launch, I have a ResourceLoader class load up all of the resources I will need. Because I have so many resource files I'm pulling from, I used the following method in code:
private static Scanner loadScanner(String fileName, ClassLoader classLoader) throws IOException, NullPointerException {
File file;
Scanner sc;
try { //to load the resource file
file = new File(classLoader.getResource(fileName).getFile());
} catch (NullPointerException npe) {
throw new NullPointerException("File " + fileName + " not found in ResourceLoader.loadScanner()");
}
sc = new Scanner(file);
return sc;
}
I call the method with something like:
String fileName = "example.csv";
ClassLoader classLoader = ClassLoader.getSystemClassLoader();
sc = loadScanner(fileName,classLoader);
The error message I am getting is:
file:\C:\...\myjar.jar!\example.csv (The filename, directory name, or volume label syntax is incorrect)
Exception in thread "main" java.lang.NullPointerException
My assumption is that the jar code is looking for a resources folder, and it's not there. How do I need to modify my code or project/jar specs to get it working the way I expect? Appreciate any help.
Also, for educational purposes, the jar file seems to suppress exceptions...? If it can't find the resource file, then why doesn't my NullPointerException catch trigger?
I am trying to read a properties folder from this path with respect to the repository root:
rest/src/main/resources/cognito.properties
I have a Class CognitoData from this path: rest/src/main/java/com/bitorb/admin/webapp/security/cognito/CognitoData.java which loads the Properties folder using this code, and it runs fine:
new CognitoProperties().loadProperties("rest/src/main/resources/cognito.properties");
#Slf4j
public class CognitoProperties {
public Properties loadProperties(String fileName) {
Properties cognitoProperties = new Properties();
try {
#Cleanup
FileInputStream fileInputStream = new FileInputStream(fileName);
cognitoProperties.load(fileInputStream);
} catch (IOException e) {
log.error("Error occured. Exception message was [" + e.getMessage() + "]");
}
return cognitoProperties;
}
}
However, when I call CognitoData from a test class located in rest/src/test/java/com/bitorb/admin/webapp/security/cognito/CognitoServiceTest.java , I get this error:
[rest/src/main/resources/cognito.properties (No such file or directory)]
Can anybody shed light on why this is happening?
File directory is not actually relative in that case. You need to provide appropriate file path for this. If you are already using spring boot, then
you can change your code to:
// this will read file from the resource folder.
InputStream inputStream = getClass().getClassLoader()
.getResourceAsStream("cognito.properties");
cognitoProperties.load(inputStream);
Otherwise you need to provide the full absolute path. new CognitoProperties().loadProperties("/absolutepath/..../cognito.properties")
I don't know what you're using for testing, but I suspect that the working directory when you run tests is not the project root.
One solution is to use an absolute path instead:
/absolute/path/to/project/rest/src/main/resources/cognito.properties
Or maybe check what is the working directory during testing and see if it can be changed to the project root.
This question already has answers here:
java.io.FileNotFoundException: the system cannot find the file specified
(8 answers)
Closed 4 years ago.
I have a csv file in the same path as everything else. Now, when I try to create a File object:
public void getMenu() {
File fileMenu = new File("FastFoodMenu.csv");
try {
Scanner inputStream = new Scanner(fileMenu);
while (inputStream.hasNext()) {
String data = inputStream.next();
System.out.println(data);
}
} catch (FileNotFoundException ex) {
Logger.getLogger(FileHandler.class.getName()).log(Level.SEVERE, null, ex);
}
}
it throws a FileNotFoundException.
the absolute path to all files in the project is:
C:\Users\kenyo\Documents\NetBeansProjects\OrderFastFood\src\fastfoodorderingsystem
I also checked the name a couple of times. fileMenu.exists() returns false.
First, in your root/working directory (in your case it's the folder containing your project), create a folder called 'menus', here you can store all your menus (so you can play around with multi-file input).
Second, move your FastFoodMenu.csv file to that menus folder.
The FastFoodMenu.csv relative path should now look like this: OrderFastFood\menus\FastFoodMenu.csv.
Third, get your working directory from the System properties. This is the folder in which your program is working in. Then, get a reference (File object) to the menus folder.
Lastly, get a reference to the file in question inside the menu folder. When you get to multi-file reading (and at some point, multi-folder reading), you're gonna want to get the files inside the menu folder as a list so that's why I say to just get the menus folder as it's own reference (or just get the file without the isolated reference to the parent aka '\menus\').
So your code should really look like this:
public void getMenu() {
final File workingDir = File(System.getProperty("user.dir"));
final File menusDir = File(workingDir, "menus");
final File fastFoodMenu = File(menusDir, "FastFoodMenu.csv");
try {
final FileInputStream fis = new FileInputStream(fastFoodMenu);
final BufferedInputStream bs = new BufferedInputStream(fis);
while((l = bs.readLine()) != null) {
System.out.println(l);
}
} catch(FileNotFoundException e) {
System.out.println(e.getMessage());
e.printStackTrace()
}
}
This is all psuedocode but that should at least get you started. Make sure to use BufferedInputStream for efficiency, and when reading files, always pass them into FileInputStream's. It's much better than using the Scanner class. I should also mention that when creating a File object, you're not actually creating a file. What you're doing is your're creating an object, giving it the data you want it to have (such as whether it's a folder, and if it is, what child files/folders do you want it to have, whether it's protected or not, hidden or not, etc) before actually telling the system to create the file with everything else.
Your csv file is probably at the wrong place. You're just specifying the file name, which is a relative path.
Relative paths are always resolved against the working directory of your application, not against the directory where your source file(s) are.
To solve the issue, you can
move the files to the real working directory.
use an absolute path (not advisable!)
specify the folder of your data files as program argument or in a config file (in your working directory)
put the files somewhere into the classpath of your application and load them from there via classloader. Note that files that are in your classpath are usually packed with your application and hence not easily modifiable by the user, so this solution doesn't work if the file must be changed by the user.
I have been working on a project that requires the user to "install" the program upon running it the first time. This installation needs to copy all the resources from my "res" folder to a dedicated directory on the user's hard drive. I have the following chunk of code that was working perfectly fine, but when I export the runnable jar from eclipse, I received a stack trace which indicated that the InputStream was null. The install loop passes the path of each file in the array list to the export function, which is where the issue is (with the InputStream). The paths are being passed correctly in both Eclipse and the runnable jar, so I doubt that is the issue. I have done my research and found other questions like this, but none of the suggested fixes (using a classloader, etc) have worked. I don't understand why the method I have now works in Eclipse but not in the jar?
(There also exists an ArrayList of File called installFiles)
private static String installFilesLocationOnDisk=System.getProperty("user.home")+"/Documents/[project name]/Resources/";
public static boolean tryInstall(){
for(File file:installFiles){
//for each file, make the required directories for its extraction location
new File(file.getParent()).mkdirs();
try {
//export the file from the jar to the system
exportResource("/"+file.getPath().substring(installFilesLocationOnDisk.length()));
} catch (Exception e) {
return false;
}
}
return true;
}
private static void exportResource(String resourceName) throws Exception {
InputStream resourcesInputStream = null;
OutputStream resourcesOutputStream = null;
//the output location for exported files
String outputLocation = new File(installFilesLocationOnDisk).getPath().replace('\\', '/');
try {
//This is where the issue arises when the jar is exported and ran.
resourcesInputStream = InstallFiles.class.getResourceAsStream(resourceName);
if(resourcesInputStream == null){
throw new Exception("Cannot get resource \"" + resourceName + "\" from Jar file.");
}
//Write the data from jar's resource to system file
int readBytes;
byte[] buffer = new byte[4096];
resourcesOutputStream = new FileOutputStream(outputLocation + resourceName);
while ((readBytes = resourcesInputStream.read(buffer)) > 0) {
resourcesOutputStream.write(buffer, 0, readBytes);
}
} catch (Exception ex) {
ex.printStackTrace();
System.exit(1);
} finally {
//Close streams
resourcesInputStream.close();
resourcesOutputStream.close();
}
}
Stack Trace:
java.lang.Exception: Cannot get resource "/textures\gameIcon.png" from Jar file.
All help is appreciated! Thanks
Stack Trace:
java.lang.Exception: Cannot get resource "/textures\gameIcon.png" from Jar file.
The name if the resource is wrong. As the Javadoc of ClassLoader.getResource(String) describes (and Class.getResourceAsStream(String) refers to ClassLoader for details):
The name of a resource is a /-separated path name that identifies
the resource.
No matter whether you get your resources from the File system or from a Jar File, you should always use / as the separator.
Using \ may sometimes work, and sometimes not: there's no guarantee. But it's always an error.
In your case, the solution is a change in the way that you invoke exportResource:
String path = file.getPath().substring(installFilesLocationOnDisk.length());
exportResource("/" + path.replace(File.pathSeparatorChar, '/'));
Rename your JAR file to ZIP, uncompress it and check where did resources go.
There is a possibility you're using Maven with Eclipse, and this means exporting Runnable JAR using Eclipse's functionality won't place resources in JAR properly (they'll end up under folder resources inside the JAR if you're using default Maven folder names conventions).
If that is the case, you should use Maven's Assembly Plugin (or a Shade plugin for "uber-JAR") to create your runnable JAR.
Even if you're not using Maven, you should check if the resources are placed correctly in the resulting JAR.
P.S. Also don't do this:
.getPath().replace('\\', '/');
And never rely on particular separator character - use java.io.File.separator to determine system's file separator character.
I'm using Spring's Resource abstraction to work with resources (files) in the filesystem. One of the resources is a file inside a JAR file. According to the following code, it appears the reference is valid
ResourcePatternResolver resourceResolver = new PathMatchingResourcePatternResolver();
// The path to the resource from the root of the JAR file
Resource fileInJar = resourcePatternResolver.getResources("/META-INF/foo/file.txt");
templateResource.exists(); // returns true
templateResource.isReadable(); // returns true
At this point, all is well, but then when I try to convert the Resource to a File
templateResource.getFile();
I get the exception
java.io.FileNotFoundException: class path resource [META-INF/foo/file.txt] cannot be resolved to absolute file path because it does not reside in the file system: jar:file:/D:/m2repo/uic-3.2.6-0.jar!/META-INF/foo/file.txt
at org.springframework.util.ResourceUtils.getFile(ResourceUtils.java:198)
at org.springframework.core.io.ClassPathResource.getFile(ClassPathResource.java:174)
What is the correct way to get a File reference to a Resource that exists inside a JAR file?
What is the correct way to get a File
reference to a Resource that exists
inside a JAR file?
The correct way is not doing that at all because it's impossible. A File represents an actual file on a file system, which a JAR entry is not, unless you have a special file system for that.
If you just need the data, use getInputStream(). If you have to satisfy an API that demands a File object, then I'm afraid the only thing you can do is to create a temp file and copy the data from the input stream to it.
If you want to read it, just call resource.getInputStream()
The exception message is pretty clear - the file does not reside on the file-system, so you can't have a File instance. Besides - what will do do with that File, apart from reading its content?
A quick look at the link you provided for Resource documentation, says the following:
Throws: IOException if the resource cannot be resolved as absolute file path,
i.e. if the resource is not available in a file system
Maybe the text file is inside a jar? In that case you will have to use getInputStream() to read its contents.
Just adding an example to the answers here. If you need a File (and not just the contents of it) from within your JAR, you need to create a temporary file from the resource first. (The below is written in Groovy):
InputStream inputStream = resourceLoader.getResource('/META-INF/foo/file.txt').inputStream
File tempFile = new File('file.txt')
OutputStream outputStream = new FileOutputStream(tempFile)
try {
IOUtils.copy(inputStream, outputStream)
} catch (IOException e) {
// Handle exception
} finally {
outputStream.close()
}