Spring------SpringAOP的@Aspect注解不起作用的问题

在学习用SpringBoot时用注解的方式配置SpringAOP发现并没有起到作用，最后在网上找到了问题所在，在此记录一下。

参考自：https://stackoverflow.com/questions/9633840/spring-autowired-bean-for-aspect-aspect-is-null/11445798#11445798

 这是项目的目录结构：

 LogAspect.java

package com.vmars.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

@Component
@Aspect
public class LogAspect {
    private static final Logger logger = LoggerFactory.getLogger(LogAspect.class);

    @Before(value = "execution(* com.vmars.controller.IndexController.*(..))")
    public void beforeMethod(JoinPoint joinPoint) {

        StringBuilder sb = new StringBuilder();
        for (Object arg : joinPoint.getArgs()) {
            sb.append("arg: " + arg.toString() + " | ");
        }

        logger.info("Before Method : " + sb.toString());
    }

    @After(value = "execution(* com.vmars.controller.IndexController.*(..))")
    public void afterMethod(JoinPoint joinPoint) {
        logger.info("After Method.");
    }
}

IndexControl.java

package com.vmars.controller;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;

@Controller
public class IndexController {

    private static final Logger logger = LoggerFactory.getLogger(IndexController.class);


    @RequestMapping(path = {"/"})
    @ResponseBody
    public String index() {

        logger.info("Visit Index Page");

        return "Hello vMars";
    }

}

1.首先排查自己的pom.xml，观察是不是把所对应需要的包都导进去了。

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.vmars</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

        <!-- 以下是 SpringAOP 所需要的包 -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>4.3.14.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>2.2.2</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

        <!-- 以上是 SpringAOP 所需要的包 -->




        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-velocity</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-test</artifactId>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2.如果所需要的包都已导入，但还是不起作用观察是否写对格式

这里注意除了@Aspect注解外，还要加上@Component注解

在官方文档中有写到：(文章地址)

You may register aspect classes as regular beans in your Spring XML configuration, or autodetect them through classpath scanning - just like any other Spring-managed bean. However, note that the @Aspect annotation is not sufficient for autodetection in the classpath: For that purpose, you need to add a separate @Component annotation (or alternatively a custom stereotype annotation that qualifies, as per the rules of Spring’s component scanner).

有道翻译：

您可以将方面类注册为Spring XML配置中的常规bean，或者通过类路径扫描自动检测它们——就像任何其他Spring管理的bean一样。但是，请注意@Aspect注释并不足以在类路径中进行自动检测:为此，您需要添加一个单独的@Component注释(或者根据Spring组件扫描器的规则，添加一个符合条件的自定义原型注释)。