Spring AOP中如何单独定义切点？

package com.tianmaying.aopdemo.aspect;

import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;

@Aspect //1
@Component
public class LogAspect {

    @Pointcut("execution(* com.tianmaying.aopdemo..*.bookFlight(..))") //2
    private void logPointCut() {
    }

    @AfterReturning(pointcut = "logPointCut()", returning = "retVal") //3
    public void logBookingStatus(boolean retVal) {  //4
        if (retVal) {
            System.out.println("booking flight succeeded!");
        } else {
            System.out.println("booking flight failed!");
        }
    }
}