spring boot项目08：切面（AOP）-基础使用

JAVA 8

Spring Boot 2.5.3

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百度百科：

在软件业，AOP 为 Aspect Oriented Programming 的缩写，意为：面向切面编程，通过预编译方式和运行期间动态代理实现程序功能的统一维护的一种技术。

涉及注解：

@Aspect、@Pointcut、

@Around、@Before、@AfterReturning、@AfterThrowing、@AfterThrowing、@After

涉及接口：

JoinPoint

ProceedingJoinPoint

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jar包：aspectjweaver-x.y.z.jar

AOP 属于 Spring Framework的内容，在官文 Spring Framework Documentation->Core 可以找到介绍。

在本文的 Spring Boot 版本使用时，不需要使用 @EnableAspectJAutoProxy 注解了。

找原因：

spring-boot-autoconfigure 包的 META-INFO/spring.factories 中有下面的定义：AopAutoConfiguration

# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,

官文中 spring.aop.auto 默认为 true：

示例代码：

package org.lib.mysqlhello.common;

import javax.servlet.http.HttpServletRequest;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import lombok.extern.slf4j.Slf4j;

@Slf4j
@Aspect
@Component // 必须
public class WebLogAspect {

	@Autowired
	private HttpServletRequest req;
	
//	@Autowired
//	private HttpServletResponse resp;

	// org.lib.mysqlhello.user.controller包下 所有public方法
    // 注意通配符的使用！
    @Pointcut(value="execution(public * org.lib.mysqlhello.user.controller..*.*(..))")
	private void ptUserController() {
	}
	
	/**
	 * Before
	 * @author ben
	 * @date 2021-08-22 11:32:28 CST
	 * @param joinPoint
	 */
    // 等效
//	@Before(value="execution(public * org.lib.mysqlhello.user.controller..*.*(..))")
	@Before(value="ptUserController()")
	public void logBeforeUserController(JoinPoint joinPoint) {
		log.info("请求before:{}", req.getRequestURI());
	}
	
	/**
	 * Around
	 * @author ben
	 * @date 2021-08-22 11:32:21 CST
	 * @param pjp
	 * @return
	 * @throws Throwable
	 */
    // 等效
//	@Around(value="execution(public * org.lib.mysqlhello.user.controller..*.*(..))")
	@Around(value="ptUserController()")
	public Object logAroundUserController(ProceedingJoinPoint pjp) throws Throwable {
		try {
			// 在 @Before 之后执行
			log.info("请求around: {}", req.getRequestURI());
			return pjp.proceed();
		} catch (Exception e) {
			log.error("请求around发生异常：{}, e={}", req.getRequestURI(), e.getMessage());
			throw e;
			
			// return后，全局异常处理无效了！
//			return ResultVO.getFailed(500, "发生异常-@Aspect-Around", e.getMessage());
		} finally {
			// 在 @After 之后执行
			log.info("请求around-finally: {}", req.getRequestURI());
		}
	}
	
	/**
	 * AfterReturning
	 * @author ben
	 * @date 2021-08-22 11:32:15 CST
	 */
    // 等效
//	@AfterReturning(value="execution(public * org.lib.mysqlhello.user.controller..*.*(..))")
//	@AfterReturning(value="ptUserController()")
	@AfterReturning(pointcut="ptUserController()")
	public void logAfterReturningUserController() {
		log.info("请求afterReturning:{}", req.getRequestURI());
	}

	/**
	 * AfterThrowing 1-不抛出异常，没有throwing属性
	 * @author ben
	 * @date 2021-08-22 11:30:33 CST
	 */
    // 等效
//	@AfterThrowing(value="execution(public * org.lib.mysqlhello.user.controller..*.*(..))")
//	@AfterThrowing(value="ptUserController()")
	@AfterThrowing(pointcut = "ptUserController()")
	public void logAfterThrowingUserController() {
		log.info("请求afterThrowing:{}, nothing...", req.getRequestURI());
	}
	
	/**
	 * AfterThrowing 2-抛出异常，必须有throwing属性
	 * @author ben
	 * @date 2021-08-22 11:31:02 CST
	 * @param ex
	 */
    // 等效
//	@AfterThrowing(value="execution(public * org.lib.mysqlhello.user.controller..*.*(..))", throwing = "ex")
//	@AfterThrowing(value="ptUserController()", throwing = "ex")
	@AfterThrowing(pointcut = "ptUserController()", throwing = "ex")
	public void logAfterThrowingUserController(Exception ex) {
		log.info("请求afterThrowing:{}, ex.msg={}", req.getRequestURI(), ex.getMessage());
	}
	
	/**
	 * After
	 * @author ben
	 * @date 2021-08-22 11:31:59 CST
	 */
    // 等效
//	@After(value="execution(public * org.lib.mysqlhello.user.controller..*.*(..))")
	@After(value="ptUserController()")
	public void logAfterUserController() {
		log.info("请求after:{}", req.getRequestURI());
	}
	
}

测试结果1：正常请求，，注意顺序