简单aop框架实现

接口IUser

public interface IUser {
    public void login();
    public void logout();
}

接口IAdvice

public interface IAdvice {
    public void beforeAdvice();
    public void afterAdvice();
}

IUser接口实现类(UserImp类)

public class UserImp implements IUser {
    @Override
    public void login() {
        System.out.println("登陆成功!");
    }

    @Override
    public void logout() {
        System.out.println("登出成功!");
    }
}

IAdvice接口实现类(AdviceImp类)

public class AdviceImp implements IAdvice {
    @Override
    public void beforeAdvice() {
        System.out.println("验证身份中");
    }

    @Override
    public void afterAdvice() {
        System.out.println("验证成功!");
    }
}

动态代理类(ProxyFactory类)

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class ProxyFactory implements InvocationHandler {
    private Object target;//代理目标类
    private AdviceImp advice;//通知类

    public Object getProxy(){
        Class<?> tclass = target.getClass();
        return Proxy.newProxyInstance(tclass.getClassLoader()
                ,tclass.getInterfaces()
                ,this);
    }

    public void setTarget(Object target) {
        this.target = target;
    }

    public void setAdvice(Object advice) {
        this.advice = (AdviceImp) advice;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        advice.beforeAdvice();
        Object obj = method.invoke(target);
        advice.afterAdvice();
        return obj;
    }
}

组装类(BeanFactory类)

import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Properties;

public class BeanFactory {
    private Properties prop=new Properties();
    public BeanFactory(InputStream in)throws IOException {
        prop.load(in);
    }
	
	//组装代理类
    public Object getBean(String name){
        Object bean=null;
        String classname = prop.getProperty(name);
        try {
            Class<?> aClass = Class.forName(classname);
            Object target = Class.forName(prop.getProperty(name + ".target"))
                    .getDeclaredConstructor()
                    .newInstance();
            Object advice = Class.forName(prop.getProperty(name + ".advice"))
                    .getDeclaredConstructor()
                    .newInstance();
            bean = Class.forName(classname)
                    .getDeclaredConstructor()
                    .newInstance();
            PropertyDescriptor[] propertyDescriptors = Introspector.getBeanInfo(Class.forName(classname)).getPropertyDescriptors();
            for(PropertyDescriptor pd:propertyDescriptors){
                String propname = pd.getName();
                Method writeMethod = pd.getWriteMethod();
                if(propname.equals("target")){
                    writeMethod.invoke(bean,target);
                }else if(propname.equals("advice")){
                    writeMethod.invoke(bean,advice);
                }
            }

        }catch (ClassNotFoundException|NoSuchMethodException e){
            e.printStackTrace();
        }catch ( InvocationTargetException|IllegalAccessException e){
            e.printStackTrace();
        }catch (InstantiationException| IntrospectionException e){
            e.printStackTrace();
        }

        return bean;
    }
}

属性文件(config.properties)

bean.advice=aop.AdviceImp
bean.target=aop.UserImp
bean=aop.ProxyFactory

测试类(AopTest类)

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

public class AopTest {
    public static void main(String[] args) {
        try {
            //FileInputStream in = new FileInputStream("D:\\java\\test\\src\\aop\\config.properties");
            InputStream in = Thread.currentThread().getContextClassLoader().getResourceAsStream("aop/config.properties");
            BeanFactory beanFactory=new BeanFactory(in);

            ProxyFactory bean=(ProxyFactory) beanFactory.getBean("bean");
            IUser proxy = (IUser) bean.getProxy();
            proxy.login();
            proxy.logout();
        }catch (IOException e){
            e.printStackTrace();
        }

    }
}

结果

"C:\Program Files\Java\jdk-9.0.4\bin\java.exe" "-javaagent:D:\Program Files\JetBrains\IntelliJ IDEA 2018.3.4\lib\idea_rt.jar=6057:D:\Program Files\JetBrains\IntelliJ IDEA 2018.3.4\bin" -Dfile.encoding=UTF-8 -classpath "D:\java\test\bin;D:\java\test\libs\guava-27.0-jre.jar;D:\Program Files\JetBrains\IntelliJ IDEA 2018.3.4\lib\junit.jar;D:\java\test\libs\apache-mina-2.0.20\dist\mina-core-2.0.20.jar;D:\java\test\libs\apache-mina-2.0.20\lib\slf4j-api-1.7.26.jar" aop.AopTest
验证身份中
登陆成功!
验证成功!
验证身份中
登出成功!
验证成功!