1 ProxyFactory类分析

前言：在AOP增强的Bean，是在Bean的后置处理器我们跟到AbstractAutoProxyCreator的createProxy方法。(飞机票 https://blog.csdn.net/qq_34125999/article/details/104572875 详细的介绍了AOP和AOP加强类)

AOP的代理工厂，此类提供了一种在自定义用户代码中获取和配置AOP代理实例的简单方法

(1) setTarget，创建一个单例的代理对象

/**
* Set the given object as target.
* Will create a SingletonTargetSource for the object.
* @see #setTargetSource
* @see org.springframework.aop.target.SingletonTargetSource
*/
public void setTarget(Object target) {
   setTargetSource(new SingletonTargetSource(target));
}

(2) addAdvice添加代理方法，该方法实现了Advice接口

@Override
public void addAdvice(Advice advice) throws AopConfigException {
   int pos = this.advisors.size();
   addAdvice(pos, advice);
}

(3) getProxy() 获取代理对象，AOP代理的Bean是通过该方法增强的

//创建AOP代理对象并且得到对象
public Object getProxy() {
   return createAopProxy().getProxy();
}

2 MethodInterceptor类，实现了通知接口和拦截接口，用于类的加强

3 demo

(1) TeacherService

@Service
public class TeacherService {
    public void addTeacher(){
        System.out.println("add teacher");
    }
}

(2) TeacherMethodInterceptor ,创建方法拦截器如果方法名等于addTeacher时那么增强方法。（在Bean初始化时，AOP会拿到切面类，判断该类是否被加强，如果被加强获取到加强的方法)

public class TeacherMethodInterceptor implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        Object proxy=null;
        // 方法名
        String methodName = invocation.getMethod().getName();
        //如果方法名等于
        if (methodName.equals("addTeacher")){
            System.out.println("addTeacher.........before");
            proxy = invocation.proceed();
            System.out.println("addTeacher.........after");
        }
        return proxy;
    }
}

(3) 测试

public class SpringApplicationContext {
    public static void main(String[] args) {
        //1 创建代理工厂
        ProxyFactory proxyFactory = new ProxyFactory();
        //2 设置代理目标
        proxyFactory.setTarget(new TeacherService());
        //3 设置增强方法
        proxyFactory.addAdvice(new TeacherMethodInterceptor());
        //4 获取代理对象
        TeacherService proxy = (TeacherService) proxyFactory.getProxy();
        //5 执行方法
        proxy.addTeacher();
    }
}