A detailed example of AOP in spring

A detailed example of AOP in spring

Services that need to be enhanced

If you have the following service, his function is simple, print the input parameters and return the parameters.

@Servicepublic class SimpleService {    public String getName(String name) {        System.out.println(get name is:  + name);        return name;    

Defining facets and tangency points

@Component@Aspectpublic class LogAspect {    // 定义切点    @Pointcut(within(com.ydoing.service..*))    // @Pointcut(execution(* com.ydoing.service.*.*(..)))    public void pointCut() {    } }

Before enhanced processing

    // 定义Before增强处理    // 在目标方法调用之前执行增强处理    @Before(pointCut())    public void before(JoinPoint jp) {        // 获取连接点传入参数        // Object args = jp.getArgs();        System.out.println(Before增强处理--execute before target method call);    

Test output:

Before增强处理--execute before target method callget name is: Bob

afterreturning Enhancement

    // 在目标方法调用之后执行增强处理    @AfterReturning(pointcut = pointCut(), returning = ret)    public void afterReturning(JoinPoint jp, Object ret) {        System.out.println(AfterReturnin增强处理--execute after target method call, return value is ： + ret);    }

Test output:

get name is: BobAfterReturnin增强处理--execute after target method call, return value is ：Bob

Around enhancement

    @Around(pointCut())    public void around(ProceedingJoinPoint jp) {        System.out.println(Around增强--around start...);        Object[] args = jp.getArgs();        // 修改目标方法传入的参数        args[0] = around_add_ + args[0];        try {            System.out.println(修改传入参数后执行输出：);            jp.proceed(args);        } catch (Throwable e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        System.out.println(Around增强--around end);    }

Output:

Around增强--around start...修改传入参数后执行输出：get name is: around_add_BobAround增强--around end

After enhancements

    // 无论是否发生异常都会 处理    @After(pointCut())    public void after() {        System.out.println(After增强--always do no matter what happen);    }

Output:

get name is: BobAfter增强--always do no matter what happen  

afterthrowing Enhancement

    @AfterThrowing(pointcut = pointCut(), throwing = ex)    public void afterThrowing(JoinPoint jp, Throwable ex) {        System.out.println(error is:  + ex);    }

There's no exception here, there's no output.

The test code is as follows

@Configuration@EnableAspectJAutoProxy@ComponentScan(basePackages = com.ydoing.service,com.ydoing.aspect)public class AppConfig {    public static void main(String[] args) {        @SuppressWarnings(resource)        ApplicationContext ctx = new AnnotationConfigApplicationContext(AppConfig.class);        SimpleService service = ctx.getBean(SimpleService.class);        service.getName(Bob);    }}

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A detailed example of AOP in spring