Load resource file by getResourceAsStream in static method of Java

Post Date: 2018-10-10

There are three methods to load resource file in classpath and they have some differences between them.

Below two methods will treat resources name as absolute path and without leading “/”

//1
SomeClass.class.getClassLoader().getResourceAsStream(resourcesName);

//2
Thread.currentThread().getContextClassLoader().getResourceAsStream(resourcesName);

Below method will treat resources name as absolute path if it have leading “/” or as relative path if no leading “/”

//3
SomeClass.class.getClass().getResourceAsStream(resourcesName);

Load resource file by getResourceAsStream for webapp (from Application Server)

Sometimes static calling SomeClass.class.getClassLoader().getResourceAsStream() and SomeClass.class.getClass().getResourceAsStream() to load a resource file for webapp may not work properly as Application Server may use complex hierarchy ClassLoader for webapp. So the solution is as below:

//If call from static method
Thread.currentThread().getContextClassLoader().getResourceAsStream(resourcesName);

//If it is not from static method
this.getClass().getResourceAsStream(resourcesName);

References:

• Classpath resources
• What is the difference between Class.getResource() and ClassLoader.getResource()
• When should I use Thread.getContextClassLoader()
• Different ways of loading a file as an InputStream