根据一个接口返回该接口的所有实现类
package com.pattern.factory;import java.io.File;import java.io.IOException;import java.net.URL;import java.util.ArrayList;import java.util.Enumeration;import java.util.List;public class ClassUtil {/*** @Description: 根据一个接口返回该接口的所有类* @param c 接口* @return List<Class> 实现接口的所有类* @author LiYaoHua* @date 2012-4-5 上午11:22:24 */@SuppressWarnings("unchecked")public static List<Class> getAllClassByInterface(Class c){List returnClassList = new ArrayList<Class>();//判断是不是接口,不是接口不作处理if(c.isInterface()){String packageName = c.getPackage().getName();//获得当前包名try {List<Class> allClass = getClasses(packageName);//获得当前包以及子包下的所有类//判断是否是一个接口for(int i = 0; i < allClass.size(); i++){if(c.isAssignableFrom(allClass.get(i))){if(!c.equals(allClass.get(i))){returnClassList.add(allClass.get(i));}}}} catch (Exception e) {// TODO: handle exception}}return returnClassList;}/** * * @Description: 根据包名获得该包以及子包下的所有类不查找jar包中的* @param pageName 包名* @return List<Class> 包下所有类* @author LiYaoHua * @date 2012-4-5 上午11:26:48 */private static List<Class> getClasses(String packageName) throws ClassNotFoundException,IOException{ClassLoader classLoader = Thread.currentThread().getContextClassLoader();String path = packageName.replace(".", "/");Enumeration<URL> resources = classLoader.getResources(path);List<File> dirs = new ArrayList<File>();while(resources.hasMoreElements()){URL resource = resources.nextElement();dirs.add(new File(resource.getFile()));}ArrayList<Class> classes = new ArrayList<Class>();for(File directory:dirs){classes.addAll(findClass(directory, packageName));}return classes;}private static List<Class> findClass(File directory, String packageName) throws ClassNotFoundException{List<Class> classes = new ArrayList<Class>();if(!directory.exists()){return classes;}File[] files = directory.listFiles();for(File file:files){if(file.isDirectory()){assert !file.getName().contains(".");classes.addAll(findClass(file, packageName+"."+file.getName()));}else if(file.getName().endsWith(".class")){classes.add(Class.forName(packageName+"."+file.getName().substring(0,file.getName().length()-6)));}}return classes;}}