取得接口的所有实现

取得一个接口的所有实现class

package com.hp.util;

import java.io.File;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.List;

@SuppressWarnings("all")
public class ClassUtil {

	public static List<Class> getAllClassByInterface(Class c) {
		List<Class> list = new ArrayList<Class>();
		if (c.isInterface()) {
			String packageName = c.getPackage().getName();
			try {
				List<Class> allClass = getClasses(packageName);
				for (int i = 0; i < allClass.size(); i++) {
					if (c.isAssignableFrom(allClass.get(i))) {
						if (!c.equals(allClass.get(i))) {
							list.add(allClass.get(i));
						}
					}
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		return list;
	}

	private static List<Class> getClasses(String packageName) throws Exception{
		ClassLoader cl = Thread.currentThread().getContextClassLoader();
		String path = packageName.replace(".", "/");
		Enumeration<URL> resources = cl.getResources(path);
		List<File> dirs = new ArrayList<File>();
		while (resources.hasMoreElements()) {
			URL resource = resources.nextElement();
			dirs.add(new File(resource.getFile()));
		}
		List<Class> list = new ArrayList<Class>();
		for (File directory : dirs) {
			list.addAll(findClasses(directory, packageName));
		}
		return list;
	}

	private static List<Class> findClasses(File directory, String packageName) throws ClassNotFoundException{
		List<Class> list = new ArrayList<Class>();
		if (!directory.exists()) {
			return list;
		}
		File[] files = directory.listFiles();
		for (File file : files) {
			if (file.isDirectory()) {
				assert !file.getName().contains(".");
				list.addAll(findClasses(file, packageName+"."+file.getName()));
			} else if (file.getName().endsWith(".class")) {
				list.add(Class.forName(packageName+"."+file.getName().substring(0, file.getName().length() - 6)));
			}
		}
		return list;
	}
}