Spring AOP Advice 基础

1. Advice 增强

• Advice 增强，定义拦截之后方法要做什么
• 接口 org.aopalliance.aop.Advice
• 5 种增强
  • MethodBeforAdvice 前置增强
  • AfterReturningAdvice 后置增强
  • MethodInterceptor 环绕增强
  • ThrowsAdvice 异常抛出增强
  • IntroductionInterceptor 引介增强，通过扩展DelegatingIntroductionInterceptor来实现引介增强

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2. MethodInterceptor

• 环绕通知拦截器

2.1 普通用法

public class BusinessInterceptor implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        System.out.println("before...");
        // 通过反射调用目标方法
        Object obj = invocation.proceed();
        System.out.println("after...");
        return obj;
    }
}

2.2 Advisor

public class MyInterceptor implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        // do something
        return invocation.proceed();
    }
}
@Configuration
public class BusinessInterceptorConfig {
    public static final String execution = "execution(* com.example.concrete.interceptor.*.*(..))";
    @Bean
    public Advisor defaultPointcutAdvisor() {
        MyInterceptor interceptor = new MyInterceptor();
        DefaultPointcutAdvisor advisor = new DefaultPointcutAdvisor();
        AspectJExpressionPointcut pointcut = new AspectJExpressionPointcut();
        pointcut.setExpression(execution);
        advisor.setPointcut(pointcut);
        advisor.setAdvice(interceptor);
        return advisor;
    }
}