Java dynamically loads classes from the jar file

Because of the need for development, you need to dynamically load classes based on the configuration, so simply test the Java dynamic load class

Defining interfaces

Package Loader;public interface Helloiface {public String hello (); Public String Sayhi ();}

Implementing interfaces

Implement this interface in other plug-in classes and export it as a jar, such as D:/tmp/test.jar

Package Loader;public class Helloimpl implements helloiface{@Overridepublic String Hello () {return "Hello,java World";} @Overridepublic String Sayhi () {return "Hi,java World";}}

Dynamic Load Class

Import Java.net.url;import Java.net.urlclassloader;import loader. Helloiface;public class Main {public static void Main (string[] args) {String ClassPath = "loader. Helloimpl ";//The Class name of the class that needs to be loaded in the jar string jarpath =" File:///D:/tmp/test.jar ";//The URLClassLoader of the file where the jar is located cl;try {// Get a class loader from the jar file CL = new URLClassLoader (new url[] {new URL (Jarpath)});//load from loader classclass<?> c = Cl.loadclass (c Lasspath);//Instantiate an object from class Helloiface Impl = (helloiface) c.newinstance ();//Call the class method in the Jar System.out.println (Impl.hello ()); System.out.println (Impl.sayhi ());} catch (Exception e) {e.printstacktrace ();}}}

Java dynamically loads classes from the jar file