The methods getResourceAsStream("") and getResource("") are often used to get the configuration file specified in the compilation path. The usage is similar. The following uses getResource("") as an example to show its correct usage:

	/**
	 * no package
	 */
	 System.out.println(this.getClass().getResource("template.xml").getPath());//relative to the template.xml under the current Class path
	 System.out.println(this.getClass().getResource("/template.xml").getPath());//classpath template.xml under the root path
	 System.out.println(this.getClass().getClassLoader().getResource("template.xml").getPath());//classpath template.xml under the root path
	/**
	 * package
	 */
	 System.out.println(this.getClass().getResource("package/template.xml").getPath());//relative to the template.xml under the current Classpath/package path
	 System.out.println(this.getClass().getResource("/package/template.xml").getPath());//classpath template/xml under root path/package path
	 System.out.println(this.getClass().getClassLoader().getResource("package/template.xml").getPath());//classpath template/xml under the root path/package path
		

Wrong usage (note the slash):

	/**
	  * no package
	 */
	 System.out.println(this.getClass().getClassLoader().getResource("/template.xml").getPath());//classpath template.xml under the root path
	/**
	 * package
	 */
	 System.out.println(this.getClass().getClassLoader().getResource("/package/template.xml").getPath());//classpath template/xml under the root path/package path
		

Note: When getting the configuration file in the Jar package, it is recommended to encode by getResourceAsStream("").

JAVA basic popularity:

Classloader class loader for loading Java classes into a Java virtual machine. Different from ordinary programs. Java programs (class files) are not native executables. When running a Java program, first run the JVM (Java Virtual Machine), then load the Java class into the JVM, the part responsible for loading the Java class is called Class Loader.

The JVM itself contains a ClassLoader called Bootstrap ClassLoader. Like the JVM, the BootstrapClassLoader is implemented in native code and is responsible for loading the core JavaClass (that is, all classes starting with java.*). In addition, the JVM will also provide two ClassLoaders, which are written in Java and loaded by BootstrapClassLoader. The Extension ClassLoader is responsible for loading the extended Java class (for example, all classes starting with javax.* and classes stored in the JRE's ext directory). The ApplicationClassLoader is responsible for loading the application's own classes.

When running a program, the JVM starts, runs bootstrapclassloader, the ClassLoader loads the java core API (ExtClassLoader and AppClassLoader are also loaded at this time), then calls ExtClassLoader to load the extension API, and finally AppClassLoader loads the Class defined in the CLASSPATH directory, which is The most basic loading process of a program.

Best Wishes For You!