Spring AOP注解快速入门

1、引入spring坐标、aspectj坐标、junit坐标、spring-test坐标

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.2.3.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.9.3</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>5.2.3.RELEASE</version>
</dependency>
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
</dependency>

2、编写接口类

public interface TargetInterface {
    public void doSomething();
}

3、编写接口实现类

@Component("targetInterfaceImpl")
public class TargetInterfaceImpl implements TargetInterface {
    public void doSomething() {
        System.out.println("doSomething running......");
    }
}

4、编写切面类

@Component("aspect")
@org.aspectj.lang.annotation.Aspect//标注该类为一个切面类
public class Aspect {
    //配置前置通知
//    @Before("Aspect.pointcut()") //第一种写法
    @Before("pointcut()") //第二种写法
    public void before(){
        System.out.println("前置增强");
    }
    @Pointcut("execution(public void com.itheima.aop.*.*(..))")
    public void pointcut(){}
}

5、配置applicationContext.xml

　　1)引入context命名空间和aop命令空间　

<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/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">

　　2）开启组件扫描和aop自动代理

<!--开启组件扫描-->
<context:component-scan base-package="com.itheima"/>
<!--aop自动代理-->
<aop:aspectj-autoproxy/>

6、代码测试

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class Test {
    @Autowired
    private TargetInterface targetInterface;
    @org.junit.Test
    public void testAop(){
        targetInterface.doSomething();
    }
}

7、遇到的问题

　　如果采用切点表达式的抽取的方式定义切点表达式可能会出现

　　Caused by: java.lang.IllegalArgumentException: error at ::0 can't find referenced pointcut pointcut

　　但是如果不采用切点表达式的抽取，则不会报错

　@Before("execution(public void com.itheima.aop.*.*(..))")
　这可能是由于aspectj的版本导致的，
　本人在使用1.8.4时报错，将版本修改为1.9.4则不报错