[Java知识库]Spring AOP的基本使用 Demo

这个Demo是个Demo，基于main启动

启动配置类

@Configuration
@ComponentScan("yuanma.xxx")
//@Import(ImportTest.class)
@EnableAspectJAutoProxy //开启AOP
public class BeanConfig {
}

启动测试类

public class AOPTestApp {


    public static void main(String[] args) {

       //xml();
        ann();
    }

    /**
     * 基于注解的入口
     */
    public static void ann() {

        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(BeanConfig.class);
        JiSuanQi jiSuanQiImpl = (JiSuanQi) context.getBean("jiSuanQiImpl");
        jiSuanQiImpl.jia(2,2);
    }
}

被加强的类

/**
 * 计算器
 */
public interface JiSuanQi {

    int jia(int a, int b);
    int jian(int a, int b);
    int cheng(int a, int b);
    int chu(int a, int b);
}

/**
 * 计算器
 */
@Component
public class JiSuanQiImpl implements JiSuanQi {

    @Override
    public int jia(int a, int b) {
        System.out.println("执行了a+b");
        return a + b;
    }

    @Override
    public int jian(int a, int b) {
        System.out.println("执行了a-b");
        return a-b;
    }

    @Override
    public int cheng(int a, int b) {
        System.out.println("执行了a*b");
        return a*b;
    }

    @Override
    public int chu(int a, int b) {
        System.out.println("执行了a/b");
        return a/b;
    }
}

切面类

切面类就是定义增强代码的

/**
 * 增强计算器的切面
 */
@Component
@Aspect
public class JisuanqiAspect {


    @Pointcut("execution(* yuanma.leiqiang.aop..*(..))")
    public void pointCut() {}

    @Before(value = "pointCut()")
    public void before(JoinPoint joinPoint) throws Exception{
        String name = joinPoint.getSignature().getName();
        System.out.println("Before增强了方法"+ name);

    }

    @After(value = "pointCut()")
    public void after(JoinPoint joinPoint) throws Exception{
        String name = joinPoint.getSignature().getName();
        System.out.println("After增强了方法"+ name);

    }

    @AfterReturning(value = "pointCut()", returning = "result")
    public void afterReturning(JoinPoint joinPoint, Object result) throws Exception{
        String name = joinPoint.getSignature().getName();
        System.out.println("After增强了方法"+ name + "结果为"+result);

    }

    @AfterThrowing(value = "pointCut()")
    public void afterThrowing(JoinPoint joinPoint) throws Exception{
        String name = joinPoint.getSignature().getName();
        System.out.println("方法出现了异常"+ name);

    }

    @Around(value = "pointCut()")
    public Object around(ProceedingJoinPoint pjp) throws Throwable{
        String name = pjp.getSignature().getName();
        System.out.println("环绕通知=>方法执行前"+ name);

        Object object = pjp.proceed(pjp.getArgs());//执行我们的方法

        System.out.println("环绕通知=>方法执行后"+ name);
        return object;
    }
}

启动后的打印结果

环绕通知=>方法执行前jia // 环绕通知前 方法执行了
Before增强了方法jia  //前置通知执行了
执行了a+b  //原方法执行了
环绕通知=>方法执行后jia //环绕通知后 方法执行了
无返回值After增强了方法jia  //后置通知 不带返回值的方法执行
带返回值After增强了方法jia结果为4   //后置通知 带返回值的方法执行