【Spring】简单的Spring AOP注解示例

如何配置，以及相关知识

引入相关包：

<properties>
	<spring.version>3.0.5.RELEASE</spring.version>
	<aspectj.version>1.6.11</aspectj.version>
</properties>

<dependencies>

	<dependency>
		<groupId>org.springframework</groupId>
		<artifactId>spring-core</artifactId>
		<version>${spring.version}</version>
	</dependency>

	<dependency>
		<groupId>org.springframework</groupId>
		<artifactId>spring-context</artifactId>
		<version>${spring.version}</version>
	</dependency>

	<dependency>
		<groupId>org.springframework</groupId>
		<artifactId>spring-aop</artifactId>
		<version>${spring.version}</version>
	</dependency>

	<dependency>
		<groupId>org.aspectj</groupId>
		<artifactId>aspectjrt</artifactId>
		<version>${aspectj.version}</version>
	</dependency>

	<dependency>
		<groupId>org.aspectj</groupId>
		<artifactId>aspectjweaver</artifactId>
		<version>${aspectj.version}</version>
	</dependency>

	<dependency>
		<groupId>cglib</groupId>
		<artifactId>cglib</artifactId>
		<version>3.1</version>
	</dependency>

</dependencies>

在Spring配置文件开启注解、AspectJ支持、扫描基础包：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context" 
    xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
           http://www.springframework.org/schema/context 
           http://www.springframework.org/schema/context/spring-context-3.0.xsd
           http://www.springframework.org/schema/aop 
           http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">
           
    <!-- 开启注解 -->
  	<context:annotation-config/>
  	<!-- AspectJ支持 -->
  	<aop:aspectj-autoproxy />
    <!-- 扫描基础包 -->
    <context:component-scan base-package="com.nicchagil.springaop" />
    
</beans>

写两个测试的Service：

package com.nicchagil.springaop;

import org.springframework.stereotype.Service;

@Service
public class UserService {
	
	public void query(Integer id) {
		System.out.println("UserService.query()...");
	}

}

package com.nicchagil.springaop;

import org.springframework.stereotype.Service;

@Service
public class FunctionService {
	
	public void query() {
		System.out.println("FunctionService.query()...");
	}

}

切面的信息：

package com.nicchagil.springaop;

import java.util.Arrays;

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

@Aspect
@Component
public class MyAOP {
	
	@Pointcut("execution(* com.nicchagil.springaop.*Service.query(..))")
	public void myPointcut() {
	}
	
	@Before("myPointcut()")
	public void myBefore(JoinPoint joinPoint) {
		Object[] args = joinPoint.getArgs(); // 入参
		System.out.println("Before. Args : " + Arrays.toString(args));
	}
	
	@AfterReturning("myPointcut()")
	public void myAfterReturning() {
		System.out.println("AfterReturning.");
	}
	
	@AfterThrowing("myPointcut()")
	public void myAfterThrowing() {
		System.out.println("AfterThrowing.");
	}

}

下图可帮助理解通知（Advice）、切点（PointCut）、切面（Aspect）、织入（Weaving）各大术语：

入口类：

package com.nicchagil.springaop;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class HowToUse {
	
	public static void main(String[] args) {
        ApplicationContext context =
                new ClassPathXmlApplicationContext("spring.xml");
        
        UserService us = context.getBean("userService", UserService.class);
        us.query(100);
        
        FunctionService fs = context.getBean("functionService", FunctionService.class);
        fs.query();
    }

}

日志：

Before. Args : [100]
UserService.query()...
AfterReturning.
Before. Args : []
FunctionService.query()...
AfterReturning.

常用的AOP

添加AOP：

package com.nicchagil.exercise.springbootexercise.aop;

import java.lang.reflect.Method;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
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.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Configuration;

@Aspect
@Configuration
public class AopExample {

	private Logger logger = LoggerFactory.getLogger(this.getClass());

	@Pointcut("execution(* com.nicchagil.exercise.springbootexercise.service..*.*(..))")
	public void serviceAllMethodPointcut() {
	}
	
	@Around("serviceAllMethodPointcut()")
	public Object myAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
		/* 获取常用的对象 */
		Object targetObject = proceedingJoinPoint.getThis(); // 目标对象
		Object[] args = proceedingJoinPoint.getArgs(); // 入参
		Method method = ((MethodSignature) proceedingJoinPoint.getSignature()).getMethod(); // 方法对象

		this.logger.info("@Around targetObject : {}, args : {}, method : {}", targetObject, args, method);
		
		Object result = proceedingJoinPoint.proceed(); // 执行被拦截的代码
		this.logger.info("@Around result : {}", result);
		
		return result; // 记得返回
	}

	@Before("serviceAllMethodPointcut()")
	public void myBefore(JoinPoint joinPoint) {
		/* 获取常用的对象 */
		Object targetObject = joinPoint.getThis(); // 目标对象
		Object[] args = joinPoint.getArgs(); // 入参
		Method method = ((MethodSignature) joinPoint.getSignature()).getMethod(); // 方法对象

		this.logger.info("@Before targetObject : {}, args : {}, method : {}", targetObject, args, method);
	}

	@AfterReturning(value = "serviceAllMethodPointcut()", returning = "returningObject")
	public void myAfterReturning(JoinPoint joinPoint, Object returningObject) {
		/* 获取常用的对象 */
		Object targetObject = joinPoint.getThis(); // 目标对象
		Object[] args = joinPoint.getArgs(); // 入参
		Method method = ((MethodSignature) joinPoint.getSignature()).getMethod(); // 方法对象

		this.logger.info("@AfterReturning targetObject : {}, args : {}, method : {}, returningObject : {}",
				targetObject, args, method, returningObject);
	}
	
	@AfterThrowing(value = "serviceAllMethodPointcut()", throwing="throwable")
	public void myAfterThrowing(JoinPoint joinPoint, Throwable throwable) {
		/* 获取常用的对象 */
		Object targetObject = joinPoint.getThis(); // 目标对象
		Object[] args = joinPoint.getArgs(); // 入参
		Method method = ((MethodSignature) joinPoint.getSignature()).getMethod(); // 方法对象

		this.logger.info("@AfterThrowing targetObject : {}, args : {}, method : {}, throwable : {}",
				targetObject, args, method, throwable);
	}

}

日志打印（异常的情况就没演示了）：

2018-01-06 10:34:13.207  INFO 7176 --- [           main] Example$$EnhancerBySpringCGLIB$$ed744e46 : @Around targetObject : com.nicchagil.exercise.springbootexercise.service.UserService@67b100fe, args : [1], method : public com.nicchagil.exercise.springbootexercise.mapper.entity.User com.nicchagil.exercise.springbootexercise.service.UserService.selectByPrimaryKey(java.lang.Long)
2018-01-06 10:34:13.223  INFO 7176 --- [           main] Example$$EnhancerBySpringCGLIB$$ed744e46 : @Before targetObject : com.nicchagil.exercise.springbootexercise.service.UserService@67b100fe, args : [1], method : public com.nicchagil.exercise.springbootexercise.mapper.entity.User com.nicchagil.exercise.springbootexercise.service.UserService.selectByPrimaryKey(java.lang.Long)
2018-01-06 10:34:13.582  INFO 7176 --- [           main] Example$$EnhancerBySpringCGLIB$$ed744e46 : @Around result : User [id=1, name=Nick Huang, age=20, createTime=Sat Nov 25 00:00:00 CST 2017]
2018-01-06 10:34:13.582  INFO 7176 --- [           main] Example$$EnhancerBySpringCGLIB$$ed744e46 : @AfterReturning targetObject : com.nicchagil.exercise.springbootexercise.service.UserService@67b100fe, args : [1], method : public com.nicchagil.exercise.springbootexercise.mapper.entity.User com.nicchagil.exercise.springbootexercise.service.UserService.selectByPrimaryKey(java.lang.Long), returningObject : User [id=1, name=Nick Huang, age=20, createTime=Sat Nov 25 00:00:00 CST 2017]