Spring AOP原理解析

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-aop</artifactId>
</dependency>

package com.example.springbookdemo.aspect;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;
@Slf4j
@Aspect
@Component
public class TimeRecordAspect {
 @Around("execution(* com.example.springbookdemo.controller.*.*(..))")//该注解()中是要执行方法的路径
    //参数部分的ProceedingJoinPoint joinPoint即要执行的方法
    //不确定执行方法的返回类型,因此在这里设返回类型为Object
    public Object timeRecord(ProceedingJoinPoint joinPoint) throws Throwable {
        long start=System.currentTimeMillis();//记录方法执行前时间
        //执行方法
        Object proceed = joinPoint.proceed();//proceed()方法返回类型固定为Object
        long end=System.currentTimeMillis();//记录方法执行完的时间
        log.info(joinPoint.getSignature()+"方法耗时:"+(end-start)+"ms");//getSignature()用于获取执行方法名
        return proceed;
    }
}

package com.example.springaopdemo.controller;
@Slf4j
@RestController
@RequestMapping("/test")
public class TestController {
    @RequestMapping("/t1")
    public String t1(){
        log.info("执行t1");
        return "t1";
    }
    @RequestMapping("/t2")
    public boolean t2(){
        log.info("执行t2");
        return true;
    }
}

package com.example.springaopdemo.aspect;
@Aspect
@Component
@Slf4j
public class TestAspect {
    //抽取切点
    @Pointcut("execution(* com.example.springaopdemo.controller.*.*(..))")
    public void pt(){}
    //前置通知
    @Before("pt()")
    public void doBefore() {
        log.info("执行doBefore方法");
    }
    //后置通知
    @After("pt()")
    public void doAfter() {
        log.info("执行 After 方法");
    }
    //返回后通知
    @AfterReturning("pt()")
    public void doAfterReturning() {
        log.info("执行 AfterReturning 方法");
    }
    //抛出异常后通知
    @AfterThrowing("pt()")
    public void doAfterThrowing() {
        log.info("执行 doAfterThrowing 方法");
    }
    //添加环绕通知
    @Around("pt()")
    public Object doAround(ProceedingJoinPoint joinPoint)  {
        log.info("Around 方法开始执行");
        Object result = null;
        try {
            result = joinPoint.proceed();
        } catch (Throwable e) {
            throw new RuntimeException(e);
        }
        log.info("Around 方法结束执行");
        return result;
    }
}

@PointCut("execution(* com.example.service.*.*(..))")
public void serviceLayer() {}

@Before("serviceLayer()")
public void beforeService() {
    // 前置通知逻辑
}
@After("serviceLayer()")
public void afterService() {
    // 后置通知逻辑
}

@Component
@Aspect
@Slf4j
public class TestAspect2 {
    @Before("com.example.springaopdemo.aspect.TestAspect.pt()")
    public void doBefore() {
        log.info("执行doBefore2方法");
    }
}
@Component
@Aspect
@Slf4j
public class TestAspect3 {
    @Before("com.example.springaopdemo.aspect.TestAspect.pt()")
    public void doBefore() {
        log.info("执行doBefore3方法");
    }
}
@Aspect
@Component
@Slf4j
public class TestAspect {
    //抽取切点
    @Pointcut("execution(* com.example.springaopdemo.controller.*.*(..))")
    public void pt(){}
    //前置通知
    @Before("pt()")
    public void doBefore() {
        log.info("执行doBefore方法");
    }
}

//自定义注解
@Retention(RetentionPolicy.RUNTIME)//设置生命周期
@Target({ElementType.METHOD})//设置注解使用位置
public @interface TimeRecord {
}

//注解通过切面实现
@Aspect
@Component
@Slf4j
public class TimeRecordAspect {
    @Around("@annotation(com.example.springaopdemo.aspect.TimeRecord)")
    public  Object timeRecord(ProceedingJoinPoint joinPoint) throws Throwable {
        long start = System.currentTimeMillis();
        Object result = joinPoint.proceed();
        long end = System.currentTimeMillis();
        log.info(joinPoint.getSignature() + "耗时" + (end - start) + "ms");
        return result;
    }
}