Spring笔记（九） Spring基于注解的AOP

2020-10-31 | 阅读：次

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.2.8.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.9.2</version>
</dependency>

<!--junit测试相关-->
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.13</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>5.2.8.RELEASE</version>
</dependency>
</dependencies>

业务层接口及实现类

//接口
public interface IAccountService {
	//接口方法
}


//实现类，并加入相应注解，交由Spring容器管理
@Service("accountService")
public class AccountServiceImpl implements IAccountService {
    //实现接口方法
}

通知类（前置通知、后置通知、异常通知、最终通知）

//加入相应注解，交由Spring容器管理
@Component("logger")
//@Aspect表示当前类为切面类
@Aspect
public class Logger {

    @Pointcut("execution(* com.mg.service.impl.*.*(..))")
    private void pt1(){}

    //如果引用上面的方法，可以直接写@Before("execution(* com.mg.service.impl.*.*(..))")
    //前置通知
    @Before("pt1()")
    public void before() {
        System.out.println("before");
    }
    
    //后置通知
    @AfterReturning("pt1()")
    public void afterReturning() {
        System.out.println("afterReturning");
    }
    
    //异常通知
    @AfterThrowing("pt1()")
    public void afterThrowing() {
        System.out.println("afterThrowing");
    }
    
    //最终通知
    @After("pt1()")
    public void after() {
        System.out.println("after");
    }
    
    //环绕通知
    @Around("pt1()")
    public Object arroundLog(ProceedingJoinPoint pjp) {
        Object val = null;
        Object[] args = pjp.getArgs();
        try {
            System.out.println("前置通知");
            val = pjp.proceed(args);
            System.out.println("后置通知");
        } catch (Throwable throwable) {
            System.out.println("异常通知");
            throwable.printStackTrace();
        }finally {
            System.out.println("最终通知");
        }
        return val;
    }
}

注意：Spring基于注解的AOP配置会存在执行调用顺序的问题，所以注解开发时建议使用环绕通知的方式

@Before("pt1()")
引用方法时不要忘记后面的括号 pt1() 另外使用此种方法时注意aspectjweaver的版本问题，如果版本过低会出现java.lang.IllegalArgumentException: error at ::0 can't find referenced pointcut pt1 异常，测试时发现低于1.6.6的版本都会出现这个问题

配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       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Spring创建容器时需要扫描的包-->
    <context:component-scan base-package="com.mg"></context:component-scan>

    <!--配置Spring开启注解AOP的支持-->
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>

</beans>

测试

@RunWith(SpringJUnit4ClassRunner.class)
//指定配置文件
@ContextConfiguration(locations = "classpath:bean.xml")
public class MyTest {
    @Autowired
    IAccountService accountService;

    @Test
    public void test1() {
        accountService.saveAccount();
    }
}

替换配置文件，使用纯注解方式

@Configuration
@ComponentScan(basePackages = {"com.mg"})
@EnableAspectJAutoProxy
public class SpringConfig {   }


测试时注意将配置文件改为配置类：
@RunWith(SpringJUnit4ClassRunner.class)
//配置文件改为配置类
//@ContextConfiguration(locations = "classpath:bean.xml")
@ContextConfiguration(classes = SpringConfig.class)
public class MyTest {
    @Autowired
    IAccountService accountService;

    @Test
    public void test1() {
        accountService.saveAccount();
    }
}