项目中常用的工具类

package keifer.www;

 

import java.io.File;

import java.io.IOException;

import java.net.URL;

import java.util.ArrayList;

import java.util.Enumeration;

import java.util.List;

 

@SuppressWarnings("rawtypes")

public class ClassUtils {

      

       @SuppressWarnings("unchecked")

       public static List<Class> getAllClassByInterface(Class c) {// 返回这个接口的所有实现类

              List<Class> returnClassList = null;

              if (c.isInterface()) {

                     returnClassList = new ArrayList<Class>(0); // 返回结果

                     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

                            for (int i = 0; i < allClass.size(); i++) {

                                   if (c.isAssignableFrom(allClass.get(i))) { // 判断是否是同一个接口

                                          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();

                     }

              } else {// 如果不是一个接口，则不做处理

                     return new ArrayList<Class>(0);

              }

              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;

       }

 

       // 在一个目录及其所有子目录下面查找出所有的类

       private static List<Class> findClasses(File directory, String packageName) throws ClassNotFoundException {

              List<Class> classes = null;

              if (!directory.exists()) {

                     return new ArrayList<Class>(0);

              }

              classes = new ArrayList<Class>();

              File[] files = directory.listFiles();

              for (File file : files) {

                     if (file.isDirectory()) {

                            if(!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;

       }

}