java dynamic loading dynamic loading Java jar files jar and class files

public static void main(String[] args)
            throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, NoSuchMethodException,
            SecurityException, ClassNotFoundException, InstantiationException, MalformedURLException {
//         String path =
//         "/xx/.m2/repository/org/apache/commons/commons-lang3/3.1/commons-lang3-3.1.jar";
        String path = "commons-lang3-3.1.jar";//jar文件需放在工程目录下

        loadJar(path);
        Class<?> aClass = Class.forName("org.apache.commons.lang3.StringUtils");
        Object instance =aClass.newInstance (); 
        Object Strip = aClass.getDeclaredMethod ( "Strip", String. class , String. class ) .invoke (instance,
                 "[1,2,3,4,5,6,2,3,5, . 1] "," [] " ); 
        System.out.println (Strip); 

    } 

    Private  static  void loadJar (String jarpath) throws a MalformedURLException { 
        file jarFile = new new file (jarpath); // get a class where the class files from URLClassLoader methods clip, jar can also be considered a folder 

        IF (jarFile.exists () == false ) { 
            System.out.println ( "JAR file not found.");
             Return ; 
        } 

        // Get method of the class loader addURL prepared dynamic invocation 
        Method, Method = null ;
         the try { 
            Method = the URLClassLoader. Class .getDeclaredMethod ( "addURL", the URL. Class ); 
        } the catch (a NoSuchMethodException | a SecurityException E1) { 
            e1.printStackTrace (); 
        } 
        
        // get access methods, saving the original values 
        Boolean accessible = method.isAccessible ();
         the try {
             // modify access to writable 
            IF (== accessibleto false ) { 
                method.setAccessible ( to true ); 
            } 

            // Get the system class loader 
            the URLClassLoader classLoader = (the URLClassLoader) ClassLoader.getSystemClassLoader (); 
            
            // Get path jar file url 
            the java.net.URL url = jarFile.toURI () .toURL (); 
            
            // JAR url path added to the system in the path 
            Method.invoke (classLoader, url); 
        } the catch (Exception E) { 
            e.printStackTrace (); 
        } the finally {
             // writeback access 
            method.setAccessible ( Accessible); 
        } 

    }

 

Reference article:

Java dynamic loading jar and class files