java动态添加外部jar包到classpath的实例详解

String beanClassName = "com.dynamic.DynamicBean3"; Map<String,Class<?>> classMap = new HashMap<String,Class<?>>(); String filePath = "f://testDynamicBean-1.0-SNAPSHOT.jar"; String uFilePath = "file:f://testDynamicBean-1.0-SNAPSHOT.jar";  URL url1 = new URL(uFilePath); URLClassLoader urlClassLoader = new URLClassLoader(new URL[] { url1 }, Thread.currentThread()         .getContextClassLoader()); List<JarEntry> jarEntryList = new ArrayList<>(); JarFile jarFile = new JarFile(filePath); Enumeration<JarEntry> jarEntryEnumeration = jarFile.entries(); while (jarEntryEnumeration.hasMoreElements()){    JarEntry jarEntry = jarEntryEnumeration.nextElement();    if (//jarEntry.getName().startsWith(filePath) &&       jarEntry.getName().endsWith(".class")) {         jarEntryList.add(jarEntry);       }     }     for (JarEntry entry : jarEntryList) {       String className = entry.getName().replace('/', '.');       className = className.substring(0, className.length() - 6);       if(!classMap.containsKey(beanClassName)){         Class<?> loadClass = urlClassLoader.loadClass(className);         classMap.put(className,loadClass);       }     }     try {       Method printMethod = classMap.get(beanClassName).getMethod("printBean3");       printMethod.invoke(classMap.get(beanClassName).newInstance());     } catch (IllegalAccessException e) {       e.printStackTrace();     } catch (InvocationTargetException e) {       e.printStackTrace();     } catch (NoSuchMethodException e) {       e.printStackTrace();     } catch (InstantiationException e) {       e.printStackTrace();     }