1.pom引入

<!-- 切面依赖-->
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-aop</artifactId>
</dependency>

2.定义注解：AroundAnnotation

java">import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface AroundAnnotation {String value() default "";
}

3.定义切面：Aspect

java">import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.stereotype.Component;@Aspect
@Component
public class AroundAop {//  execution(* study.mapper.*(..)) @annotation(study.aop.AroundAnnotation)@Pointcut("execution(* study.mapper.*.*(..)) ")public void aspect(){}//定义@Around增强，poincut连接点使用@annotation(xxxx)进行定义 @annotation(study.aop.AroundAnnotation)@Around("@annotation(annotation)")public Object processTx(ProceedingJoinPoint joinPoint, AroundAnnotation annotation) throws Throwable {long startTime = System.currentTimeMillis();try {//AroundAnnotation annotation =joinPoint.getTarget().getClass().getAnnotation(AroundAnnotation.class);String value = annotation.value();System.out.println("arount 进入-----" + value);// 执行目标方法Object result = joinPoint.proceed();long endTime = System.currentTimeMillis();System.out.println("执行目标方法:"+ joinPoint.getSignature() + " executed in " + (endTime - startTime) + "ms");return result;} catch (Throwable throwable) {throwable.printStackTrace();} finally {System.out.println("arount 出去 -----" );}return null;}@Before("aspect()")public void before(JoinPoint joinPoint) {Object[] args = joinPoint.getArgs();    //获取方法入参System.out.println("before -- 原方法的入参是："+args);System.out.println("before -- 原方法执行前会先执行我！！参数：" + args[0]);}@AfterReturning("aspect()")public void after(JoinPoint joinPoint) {Object[] args = joinPoint.getArgs();    //获取方法入参System.out.println("AfterReturning -- 原方法执行后会执行我！！参数：" + args);}}

4.使用切面注解

java">
import com.baomidou.dynamic.datasource.annotation.DS;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import study.aop.AroundAnnotation;
import study.entity.UserInfo;@Mapper
public interface UserMapper extends BaseMapper<UserInfo> {@AroundAnnotation("AAAA")@Select("select * from t_user where id = #{id}")public UserInfo selectByIdFromMaster(@Param("id") Integer id);}

5.执行结果