After installing the Java Runtime Environment for the first time. As you can imagine, this is a much more flexible approach.The Java Runtime Environment combines with the Java Development Kit and the Java Virtual Machine to create a powerful trio of Java platform components for developing and running Java applications.
Java jar file opener how to#
InputStream inputStream = CLDR.getResourceAsStream("com/devdaily/desktopcurtain/sounds/" + soundfileName) ĪudioStream audioStream = new AudioStream(inputStream) Īs you can guess from looking at this code, this example shows how to read a resource file from a jar file in a java application, and in this approach, the resource file that I'm reading doesn't have to be in the same directory as the Java class file. Private void playSound(String soundfileName)ĬlassLoader CLDR = this.getClass().getClassLoader() While I'm working on another Java project, I just ran across another example of how to read a file from a Java jar file in this method: One more Java "read from Jar file" example
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Val file = new File(getClass.getResource("zipcode_data.csv").toURI)Īlthough the code shown is Scala, I think you can see that you can use this approach to read the file as a java.io.File instead of reading it as a stream. Here's one more example of how to do this, this time using some code from a current Scala project: This is inferred by the getClass().getResourceAsStream() method call, but I don't think I really stressed that enough earlier.Īlso, I haven't looked at it in a while, but I think you can just call the is.close() method to close all your resources, you don't have to make all the close calls I make here, but I'm not 100% positive. In this sample I've eliminated the CSVLineTokenizer and replaced it with a simple StringBuffer, and I return a plain old String at the end of the method.Īlso, if I didn't stress it properly earlier, with this approach the resource file that you're trying to read from must be in the same directory in the jar file as this class. InputStream is = getClass().getResourceAsStream(filename) Public String readFromJARFile(String filename)
Here is a slightly more simple version of that method: I haven't read through the Javadocs yet to know if all of those close statements at the end are necessary. I don't recommend this for real world programming, but it works okay for my unit testing needs today. Also note that I'm throwing any exceptions that occur rather than handling them. Note that I'm doing all of this within the context of a JUnit test method. Without a path stated before the filename (like " /foo/bar/3Columns.csv") the getResourceAsStream method looks for this text file in its current directory. In my example I have a plain text file named " 3Columns.csv" in the same directory as the class that contains this method.
The trick to reading text files from JAR files are these lines of code, especially the first line: InputStreamReader isr = new InputStreamReader(is) īufferedReader br = new BufferedReader(isr) ĬSVLineTokenizer tok = new CSVLineTokenizer(line) ĪssertEquals("Should be three columns in each row",3,tok.countTokens()) InputStream is = getClass().getResourceAsStream("3Columns.csv")
The source code to read a file from a Java Jar file uses the getClass and getResourceAsStream methods: This is useful any time you pack files and other resources into Jar files to distribute your Java application. Here's an example of some Java code I'm using to read a file (a text file) from a Java Jar file. Java jar file reading FAQ: Can you show me how a Java application can read a text file from own of its own Jar files?
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