package Reflects;

import java.io.IOException;
import java.io.InputStream;
import java.lang.annotation.Annotation;
import java.lang.annotation.Target;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/*
   注解练习1
 */
@LoadClassTest(ClassName="Reflects.Student",ClassMethod = "study")
public class ReflectDemo{
    public static void main(String[] args) throws Exception{
        Class<ReflectDemo> rdc = ReflectDemo.class;
        LoadClassTest a = rdc.getAnnotation(LoadClassTest.class);
        String classMethod = a.ClassMethod();
        String className   = a.ClassName();
        Class<?> aClass = Class.forName(className);
        Constructor<?> constructor = aClass.getConstructor();
        Object o = constructor.newInstance();
        //获取对应的方法
        Method method = aClass.getMethod(classMethod);
        method.invoke(o);
    }
}

package Reflects;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.TYPE)  //作用在类上
@Retention(RetentionPolicy.RUNTIME)
public @interface LoadClassTest {
    String ClassName();
    String ClassMethod();
}