给定一个接口返回这个接口所有实现类

package com.dobn.bdgcgl.test;  
 
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 ClassUtils {  
      
    /** 
     *  
     * 描述：给一个接口，返回这个接口的所有实现类 
     */ 
    public static List<Class> getAllClassByInterface(Class c){  
        //返回结果  
        List<Class> returnClassList = new ArrayList<Class>();  
        //如果不是一个接口则不做处理  
        if (c.isInterface()) {  
            //获取当前包名  
            String packageName = c.getPackage().getName();  
            try {  
                //获取当前包下以及子包下的所有类  
                List<Class> allClass = getClasses(packageName);  
                //判断是否是同一个接口  
                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 Auto-generated catch block  
                e.printStackTrace();  
            }  
        }  
        return returnClassList;  
    }  
      
    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(findClasses(directory, packageName));  
        }  
        return classes;  
    }  
      
    private static List<Class> findClasses(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(findClasses(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;  
    }  
 
}