import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
/**

• @author cbf4Life cbf4life@126.com I'm glad to share my knowledge with you
• all.

*/
@SuppressWarnings("all")
public class ClassUtils {

//给一个接口，返回这个接口的所有实现类
public static List<Class> getAllClassByInterface(Class c){
    List<Class> returnClassList = new ArrayList<Class>(); //返回结果

    //如果不是一个接口，则不做处理
    if(c.isInterface()){
        String packageName = c.getPackage().getName(); //获得当前的包名
        try {
            List<Class> allClass = getClasses(packageName); //获得当前包下以及子包下的所有类

            //判断是否是同一个接口
            for(int i=0;i<allClass.size();i++){
                if(c.isAssignableFrom(allClass.get(i))){ //判断是不是一个接口
                    if(!c.equals(allClass.get(i))){ //本身不加进去
                        returnClassList.add(allClass.get(i));
                    }
                }
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return returnClassList;
}

//从一个包中查找出所有的类，在jar包中不能查找
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;
}

}