Spring_Annotation_AOP-优快云博客

本文链接：https://blog.youkuaiyun.com/futureofstar/article/details/84543115

本文详细介绍了在Spring框架中如何配置服务类组件并实现自动装配，同时展示了如何编写切面类来实现前置通知，以及如何通过配置文件进行组件扫描、自动代理和注解配置。

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一。配置服务类组件


@Component
public class UserService {

	private UserDAO userDAO;


	public void add(User u){
		this.userDAO.save(u);
	}

	public UserDAO getUserDAO() {
		return userDAO;
	}
	@Resource(name="userDAOImpl")
	public void setUserDAO(UserDAO userDAO) {
		this.userDAO = userDAO;
	}

}

@Resource自动装配

二。配置applicationContext.xml文件


<?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.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
	<!-- 配置自动装配 AutowiredAnnotationBeanPostProcessor等接口，实现注入等功能 -->
	<context:annotation-config/>
	<!-- 配置扫描包路径 -->
	<context:component-scan base-package="com.job"/>
	<!-- 配置aop自动代理 -->
	<aop:aspectj-autoproxy/>

</beans>

三。编写切面类


@Aspect
@Component
public class LogInteceptor {

	@Before("execution(public void com.job.dao.UserDAOImpl.save(com.job.model.User))")
	public void beforeMethod(){
		System.out.println("Method start!");
	}
   @Pointcut("execution (public * com.job.dao..*.save(..))")
	public void method(){
	};

	@Before("method()")
	public void beforeMethod(){
		System.out.println("Method start!");
	}

	@Around("method()")
	public void around(ProceedingJoinPoint pjp) throws Throwable{
		System.out.println("around  before!");
		pjp.proceed();
		System.out.println("around after");
	}

}

注：首先一定要注册为组件@Component
其次注册为切面
@Before("execution(public void com.job.dao.UserDAOImpl.save(com.job.model.User))")
@Before表示调用方法前执行。
execution(public void com.job.dao.UserDAOImpl.save(com.job.model.User))表示执行特定的类名.方法名方法

"execution (public * com.job.dao..*.save(..))"
..表示包含子包
*表示任何类

四。测试


public class UserServiceTest {

	@Test
	public   void test(){
		ApplicationContext ac =  new ClassPathXmlApplicationContext("applicationContext.xml");
		UserService service = (UserService)ac.getBean("userService");
		User u = new User();
		u.setUsername("me haha  ");
		service.add(u);
	}
}

五。测试结果
Method start!
me haha ---haha!