I have a config.ini file I need to open that is quite far back in directory so I used File.getAbsolutePath() to set the base directory and concatenated the remainder of the path.
Printing the path, I get the correct path that I can paste into file explorer, but the object returned is null.
So I started by initializing my Properties and ClassLoader as such:
Properties prop = new Properties();
ClassLoader classLoader = Test.class.getClassLoader();
Then I create the path. I tried escaping a back slash(1) as well as forward slash(2), both return null but both paths work in file explorer.
String absPath = new File("").getAbsolutePath();
absPath = absPath.concat("\\resources\\config\\config.ini"); // (1)
absPath = absPath.concat("/resources/config/config.ini"); // (2)
then I try to set the URL to open an InputStream
URL res = Objects.requireNonNull(classLoader.getResource(absPath), "Unable to open config.ini");
InputStream is = new FileInputStream(res.getFile());
However, the following returns null.
classLoader.getResource(absPath)
I expected this to properly open the file because the path was correct. I am using Intelij and I read that I needed to add the .ini resource file under settings > compiler, which I did but that did not resolve my issue.
Thank you!
That's not the way to load resources via class-loaders.
If your classpath is something like the following ...
java -cp resources;lib/my.jar ... org.mypack.MyClass
then you load it with this path
getClassLoader().getResource("/config/config.ini");
Your classpath includes the resources folder, and the class-loader loads from there.
The absolute path of the OS is quite certainly not in classpath.
In any case, you must be certain that the resource folder is in classpath.
If your config file is not in classpath then you can't use classloaders to load that file.
Just one more thing, if your configuration is not in classpath, but in a child directory of your working dir, why can't you simply use new FileInputStream("resources/config/config.ini");
I've been trying to read and write to a file under my resources directory in my project. However, regardless of what I seem to do it doesn't allow me to do so.
This is my project hierarchy for reference:
Out of all these:
Paths.get("memes.txt")
Paths.get("resources/memes.txt")
Paths.get("/resources/memes.txt")
...
None have worked. What am I doing wrong?
Is it a Maven project ?
Try this :
//Get file from resources folder
ClassLoader classLoader = getClass().getClassLoader();
File file = new File(classLoader.getResource(fileName).getFile());
Ref : https://www.mkyong.com/java/java-read-a-file-from-resources-folder/
Your application can be packed as .jar file - a zip format.
There, or in the built classes directory should be memes.txt. A so-called resource, and in case of a jar not really a file system file. But is located on the class path.
URL url = getClass().getResource("/memes.txt");
InputStream in = getClass().getResourceAsStream("/memes.txt");
The path is relative to the package directory of the class, or absolute as above.
Try it using "../resources/memes.txt" with ".." you go up one directory from your current file (i assume that you are using the code in SwearTest.java)
I'm working on a project for school that needs to read from text files inside the project directory. I have it working but only because I have the filepath hardcoded to my computer.
i.e.
String path = "C:\\Users\\MyName\\workspace\\ProjectName\\"
If I sent it to my teacher, the filepath would result in an error.
Is there a way I can set the filepath to wherever the project is stored, from inside the project?
Just put the file name.
String path = "XPTO.txt"
This means your file is in the project root.
Resource files can be place relative to the class files in your project (in this manner, they can be packaged together with class files as a jar file). To access these from within your project, you can use Class.getResource() or Class.getResourceAsStream. For instance...
InputStream is = MyClass.class.getResourceAsStream('path/to/file');
Where 'path/to/file' is the path relative to where MyClass resides. Note the lack of a '/' at the beginning of this path - if it began with '/' it would be an absolute path relative to the highest package level of the project. Also note that one can use a relative file path to read a file external to the class package directory structure.
Just do WhateverNeedsAPath("Something") //path will be whereever/ProjectName/Something
This might help you also: How to define a relative path in java
In my application, I would like to use a resource that exist in a folder media/src/main/resources/testMediaExif
To get that path, I used this piece of code, located in media/src/main/java/com/project/MyClass.java:
ClassPathResource resource = new ClassPathResource("classpath:testMediaExif");
File file = resource.getFile();
String absolutePath = file.getAbsolutePath();
The error shown is:
java.io.FileNotFoundException: class path resource [classpath:testMediaExif] cannot be resolved to URL because it does not exist
If I change that code:
ClassPathResource resource = new ClassPathResource("testMediaExif");
The variable absolutePath takes this value:
/Users/blanca/desarrollo/media/target/test-classes/testMediaExif
Why does it point to the target path? How could I change it?
There are two problems with new ClassPathResource("classpath:testMediaExif"):
The classpath: prefix is only used in config files (e.g. XML files), and should not be used if you're using ClasspathResource directly.
classpath:testMediaExif refers to a resource in the root of the classpath, not relative to the file in which you're making the reference.
Try this instead:
new ClasspathResource("testMediaExif", getClass())
or
new ClasspathResource("testMediaExif", MyClass.class)
These will construct a refernce to a resource called testMediaExif relative to MyClass.
One more thing: ClasspathResource.getFile() will only work in the resource really is a file. If it's packed in a JAR, then it won't work.
My guess is that the absolute path issue is because of the outputDirectory in the target of your maven POM . In my project the outputDirectory war/WEB-INF/classes and the it is from here the classes get executed . If I change it to some junk value , the class no longer gets executed .
So I believe the absolute path has to do something with the location of your .class files . Hope this helps .
In my Java app I need to get some files and directories.
This is the program structure:
./main.java
./package1/guiclass.java
./package1/resources/resourcesloader.java
./package1/resources/repository/modules/ -> this is the dir I need to get
./package1/resources/repository/SSL-Key/cert.jks -> this is the file I need to get
guiclass loads the resourcesloader class which will load my resources (directory and file).
As to the file, I tried
resourcesloader.class.getClass().getResource("repository/SSL-Key/cert.jks").toString()
in order to get the real path, but this way does not work.
I have no idea which path to use for the directory.
I had problems with using the getClass().getResource("filename.txt") method.
Upon reading the Java docs instructions, if your resource is not in the same package as the class you are trying to access the resource from, then you have to give it relative path starting with '/'. The recommended strategy is to put your resource files under a "resources" folder in the root directory. So for example if you have the structure:
src/main/com/mycompany/myapp
then you can add a resources folder as recommended by maven in:
src/main/resources
furthermore you can add subfolders in the resources folder
src/main/resources/textfiles
and say that your file is called myfile.txt so you have
src/main/resources/textfiles/myfile.txt
Now here is where the stupid path problem comes in. Say you have a class in your com.mycompany.myapp package, and you want to access the myfile.txt file from your resource folder. Some say you need to give the:
"/main/resources/textfiles/myfile.txt" path
or
"/resources/textfiles/myfile.txt"
both of these are wrong. After I ran mvn clean compile, the files and folders are copied in the:
myapp/target/classes
folder. But the resources folder is not there, just the folders in the resources folder. So you have:
myapp/target/classes/textfiles/myfile.txt
myapp/target/classes/com/mycompany/myapp/*
so the correct path to give to the getClass().getResource("") method is:
"/textfiles/myfile.txt"
here it is:
getClass().getResource("/textfiles/myfile.txt")
This will no longer return null, but will return your class.
It is strange to me, that the "resources" folder is not copied as well, but only the subfolders and files directly in the "resources" folder. It would seem logical to me that the "resources" folder would also be found under `"myapp/target/classes"
Supply the path relative to the classloader, not the class you're getting the loader from. For instance:
resourcesloader.class.getClassLoader().getResource("package1/resources/repository/SSL-Key/cert.jks").toString();
In the hopes of providing additional information for those who don't pick this up as quickly as others, I'd like to provide my scenario as it has a slightly different setup. My project was setup with the following directory structure (using Eclipse):
Project/
src/ // application source code
org/
myproject/
MyClass.java
test/ // unit tests
res/ // resources
images/ // PNG images for icons
my-image.png
xml/ // XSD files for validating XML files with JAXB
my-schema.xsd
conf/ // default .conf file for Log4j
log4j.conf
lib/ // libraries added to build-path via project settings
I was having issues loading my resources from the res directory. I wanted all my resources separate from my source code (simply for managment/organization purposes). So, what I had to do was add the res directory to the build-path and then access the resource via:
static final ClassLoader loader = MyClass.class.getClassLoader();
// in some function
loader.getResource("images/my-image.png");
loader.getResource("xml/my-schema.xsd");
loader.getResource("conf/log4j.conf");
NOTE: The / is omitted from the beginning of the resource string because I am using ClassLoader.getResource(String) instead of Class.getResource(String).
When you use 'getResource' on a Class, a relative path is resolved based on the package the Class is in. When you use 'getResource' on a ClassLoader, a relative path is resolved based on the root folder.
If you use an absolute path, both 'getResource' methods will start at the root folder.
#GianCarlo:
You can try calling System property user.dir that will give you root of your java project and then do append this path to your relative path for example:
String root = System.getProperty("user.dir");
String filepath = "/path/to/yourfile.txt"; // in case of Windows: "\\path \\to\\yourfile.txt
String abspath = root+filepath;
// using above path read your file into byte []
File file = new File(abspath);
FileInputStream fis = new FileInputStream(file);
byte []filebytes = new byte[(int)file.length()];
fis.read(filebytes);
For those using eclipse + maven. Say you try to access the file images/pic.jpg in src/main/resources. Doing it this way :
ClassLoader loader = MyClass.class.getClassLoader();
File file = new File(loader.getResource("images/pic.jpg").getFile());
is perfectly correct, but may result in a null pointer exception. Seems like eclipse doesn't recognize the folders in the maven directory structure as source folders right away. By removing and the src/main/resources folder from the project's source folders list and putting it back (project>properties>java build path> source>remove/add Folder), I was able to solve this.
resourcesloader.class.getClass()
Can be broken down to:
Class<resourcesloader> clazz = resourceloader.class;
Class<Class> classClass = clazz.getClass();
Which means you're trying to load the resource using a bootstrap class.
Instead you probably want something like:
resourcesloader.class.getResource("repository/SSL-Key/cert.jks").toString()
If only javac warned about calling static methods on non-static contexts...
Doe the following work?
resourcesloader.class.getClass().getResource("/package1/resources/repository/SSL-Key/cert.jks")
Is there a reason you can't specify the full path including the package?
Going with the two answers as mentioned above. The first one
resourcesloader.class.getClassLoader().getResource("package1/resources/repository/SSL-Key/cert.jks").toString();
resourcesloader.class.getResource("repository/SSL-Key/cert.jks").toString()
Should be one and same thing?
In Order to obtain real path to the file you can try this:
URL fileUrl = Resourceloader.class.getResource("resources/repository/SSL-Key/cert.jks");
String pathToClass = fileUrl.getPath;
Resourceloader is classname here.
"resources/repository/SSL-Key/cert.jks" is relative path to the file. If you had your guiclass in ./package1/java with rest of folder structure remaining, you would take "../resources/repository/SSL-Key/cert.jks" as relative path because of rules defining relative path.
This way you can read your file with BufferedReader. DO NOT USE THE STRING to identify the path to the file, because if you have spaces or some characters from not english alphabet in your path, you will get problems and the file will not be found.
BufferedReader bufferedReader = new BufferedReader(
new InputStreamReader(fileUrl.openStream()));
I made a small modification on #jonathan.cone's one liner ( by adding .getFile() ) to avoid null pointer exception, and setting the path to data directory. Here's what worked for me :
String realmID = new java.util.Scanner(new java.io.File(RandomDataGenerator.class.getClassLoader().getResource("data/aa-qa-id.csv").getFile().toString())).next();
Use this:
resourcesloader.class.getClassLoader().getResource("/path/to/file").**getPath();**
One of the stable way to work across all OS would be toget System.getProperty("user.dir")
String filePath = System.getProperty("user.dir") + "/path/to/file.extension";
Path path = Paths.get(filePath);
if (Files.exists(path)) {
return true;
}