Spring学习之——基于注解的AOP

基于注解的AOP

常用注解

@Aspect：把当前类声明为切面类
@Before：前置通知，可以指定切入点表达式
@AfterReturning：后置【try】通知，可以指定切入点表达式
@AfterThrowing：异常【catch】通知，可以指定切入点表达式
@After：最终【finally】通知，可以指定切入点表达式
@Around：环绕通知，可以指定切入点表达式

案例

pom.xml

java 复制代码

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.by</groupId>
    <artifactId>Spring_AOP_Annotation</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- Spring常用依赖 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.1.8.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>5.1.8.RELEASE</version>
        </dependency>
    </dependencies>
</project>

DAO

java 复制代码

@Repository
public class UserDaoImpl implements UserDao {

    @Override
    public void addUser(){
        System.out.println("insert into tb_user......");
    }
}

Service

java 复制代码

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;

    public void addUser() {
        userDao.addUser();
    }
}

applicationContext.xml

java 复制代码

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        		http://www.springframework.org/schema/beans/spring-beans.xsd
        		http://www.springframework.org/schema/aop
        		http://www.springframework.org/schema/aop/spring-aop.xsd
        		http://www.springframework.org/schema/context
        		http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.by"></context:component-scan>
</beans>

测试

java 复制代码

/**
 * 模拟表现层
 */
public class Client {
    public static void main(String[] args) {
        ApplicationContext ac = 
            new ClassPathXmlApplicationContext("applicationContext.xml");
        //使用对象
        UserService userService = ac.getBean("userServiceImpl",UserService.class);
        userService.addUser();
    }
}

增强

applicationContext.xml

java 复制代码

<!-- 开启spring对注解AOP的支持 -->
<aop:aspectj-autoproxy/>

增强类

java 复制代码

@Component
@Aspect
public class MyLogger {

    @Before("execution(* com.by.service.*.*(..))")
    public void before(){
        System.out.println("方法开始时间："+new Date());
    }

    @After("execution(* com.by.service.*.*(..))")
    public void after(){
        System.out.println("方法结束时间："+new Date());
    }
}