Java如何加载外部Jar的类并通过反射调用类的方法

private static String bootClassPath = System.getProperty("sun.boot.class.path");

System.getProperty("java.class.path")

System.getProperty("java.ext.dirs")

public class JarUtils {
    /**
     * 这些默认方法不打印
     */
    private static List<String> DEFAULT_METHODS = Arrays.asList("wait", "equals", "notify", "notifyAll", "toString", "hashCode" , "getClass");

    public static void parseJar(File file) throws Exception {
        URL url = file.toURI().toURL();
        try (URLClassLoader myClassLoader = new URLClassLoader(new URL[]{url}, Thread.currentThread().getContextClassLoader())) {
            //通过jarFile和JarEntry得到所有的类
            JarFile jar = new JarFile(file);
            //返回zip文件条目的枚举
            Enumeration<JarEntry> enumFiles = jar.entries();
            JarEntry entry;
            //测试此枚举是否包含更多的元素
            while (enumFiles.hasMoreElements()) {
                entry = enumFiles.nextElement();
                if (entry.getName().indexOf("META-INF") < 0) {
                    String classFullName = entry.getName();
                    if (classFullName.endsWith(".class")) {
                        //去掉后缀.class
                        String className = classFullName.substring(0, classFullName.length() - 6)
                                .replace("/", "."); //类名
                        Class<?> myclass = myClassLoader.loadClass(className);

                        System.out.println(String.format("类名：%s", className));

                        //得到类中包含的属性
                        Method[] methods = myclass.getMethods();
                        for (Method method : methods) {
                            String methodName = method.getName();
                            if (DEFAULT_METHODS.contains(methodName)) {
                                continue;
                            }

                            //方法名
                            System.out.print(String.format("方法名：%s; ", methodName));

                            Class<?>[] parameterTypes = method.getParameterTypes(); //方法参数类型

                            System.out.print(String.format("方法参数类型：%s; ", Arrays.stream(parameterTypes)
                                    .map(Class::getSimpleName).collect(joining(","))));

                            System.out.println(String.format("方法返回类型：%s; ", method.getReturnType().getSimpleName())); //方法返回值类型
                        }
                        System.out.println("***************************");
                    }
                }
            }
        } catch (IOException e) {
            throw e;
        }
    }

}

public class JarUtils {

    public static void executeMethod(File f, String className, String methodName, Class[] classes, Object[] objects) {
        //通过URLClassLoader加载外部jar
        try (URLClassLoader urlClassLoader = new URLClassLoader(new URL[]{f.toURI().toURL()})) {
            //获取外部jar里面的具体类对象
            Class<?> targetClass = urlClassLoader.loadClass(className);
            //创建对象实例
            Object instance = targetClass.newInstance();
            //获取实例当中的方法名为show，参数只有一个且类型为string的public方法
            Method method = targetClass.getMethod(methodName, classes);
            //传入实例以及方法参数信息执行这个方法
            Object returnObj = method.invoke(instance, objects);
            System.out.println(returnObj);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}