Spring AOP的底层实现方式-代理模式

public interface TargetClass {
    void sayHello();
}

public class TargetClassImpl implements TargetClass{
    public void sayHello() {
        System.out.println("你好");
    }
}

public class JdkProxy implements InvocationHandler {
    private TargetClass targetClass;
    public Object createProxy(TargetClass targetClass){
        //传入真实实现类, 本身要做的事情会由他自己做, 代理类会额外进行其他增强操作
        this.targetClass = targetClass; 
        //获取本类类加载器
        ClassLoader classLoader = JdkProxy.class.getClassLoader();
        ///获取被代理对象的所有接口
        Class[] clazz = targetClass.getClass().getInterfaces();
        System.out.println(clazz.length);
        //生成代理类并返回
        return Proxy.newProxyInstance(classLoader, clazz, this);
    }
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("JDKProxy前置增强");
        Object obj = method.invoke(targetClass,args);
        System.out.println("JDKProxy后置增强");
        return obj;
    }
}

public class Test {
    public static void main(String[] args) {
		JdkProxy jdkProxy = new JdkProxy();
		TargetClass targetClass = new TargetClassImpl();
		TargetClass targetClass1 = (TargetClass) jdkProxy.createProxy(targetClass);
		targetClass1.sayHello();
}

public class CGlibTaretClass {
    public void sayHello(){
        System.out.println("我是CGlib,我不需要接口");
    }
}

package CGlibProxyTest;
import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;
import java.lang.reflect.Method;
public class CGlibProxy implements MethodInterceptor{
    //代理方法
    public Object createProxy(Object target){
        //创建一个动态类对象
        Enhancer enhancer = new Enhancer();
        //确定要增强的类,设置期父类
        enhancer.setSuperclass(target.getClass());
        //添加回调函数
        enhancer.setCallback(this);
        //返回创建的代理类
        return enhancer.create();
    }
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        System.out.println("CGlib前置增强");
        Object obj = methodProxy.invokeSuper(o,objects);
        System.out.println("CGlib后置增强");
        return obj;
    }
}

public class Test {
    public static void main(String[] args) {
		CGlibProxy cGlibProxy = new CGlibProxy();
        CGlibTaretClass cGlibTaretClass = new CGlibTaretClass();
        CGlibTaretClass cGlibTaretClass1 = (CGlibTaretClass)cGlibProxy.createProxy(cGlibTaretClass);
        cGlibTaretClass1.sayHello();
   }