ClassUtil

功能列表

• 获取指定 classloader 中已加载的类；
• 获取指定 classloader 中已加载且带有指定注解的类；

源代码

package com.dotions.classloader;

import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.util.Collections;
import java.util.List;
import java.util.Vector;
import java.util.stream.Collectors;

/**
 * 

 * Class 相关工具类
 * 
 * 
 * Created by wyf0931 on 2018-03-27.
 */
public class ClassUtil {

    /**
     * 获取指定 classloader 中已加载的类
     * 
     * @param cl
     */
    @SuppressWarnings("unchecked")
    public static Vector> getLoadedClasses(ClassLoader cl) {
        if (cl == null) {
            return null;
        }
        try {
            Field classes = ClassLoader.class.getDeclaredField("classes");
            classes.setAccessible(true);
            return (Vector>) classes.get(cl);
        } catch (NoSuchFieldException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 获取指定 classloader 中已加载且带有指定注解的类
     * 
     * @param cl
     * @param annotationClass
     */
    public static List> getLoadedClassesByAnnotation(ClassLoader cl,
        Class annotationClass) {
        Vector> classes = getLoadedClasses(cl);
        if (classes == null || classes.isEmpty()) {
            return Collections.emptyList();
        }
        return classes.stream().filter(c -> c.isAnnotationPresent(annotationClass)).collect(Collectors.toList());
    }
}