Spring核心之AOP（Aspect Oriented Programming）面向切面编程的三种实现方式

该文以maven工程、Spring集成Junit为开发测试环境，记录AOP三种实现方式：
1、纯配置文件； 2、配置文件+注解； 3、纯注解。

maven工程导入相关坐标

	<properties>
        <spring.version>5.0.5.RELEASE</spring.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring集成测试-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--aop织入-->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.13</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>

1：纯配置文件
Spring核心配置文件applicationContext.xml中配置

	<!--切点类-->
    <bean id="target" class="xxx.xxx.target.impl.TargetImpl"></bean>
    <!--通知类-->
    <bean id="myAspect" class="xxx.xxx.aspect.MyAspect"></bean>
    <!--配置切面:切点+通知-->
    <aop:config>
        <!--配置通知类-->
        <aop:aspect ref="myAspect">
            <!--配置增强方法、切点:该方法为前值增强-->
            <aop:before method="before" pointcut="execution(* xxx.xxx.target.impl.*.*(..))"></aop:before>
        </aop:aspect>
    </aop:config>

通知/增强类

public class MyAspect {
    //增强方法
    public void before() {
        System.out.println("before running.......");
    }
}

目标类(需要增强的类)

public class TargetImpl implements Target {
    //切点
    public void method() {
        System.out.println(" target running.......");
    }
}

测试类

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class SpringTest {
    @Autowired
    private Target target;
    @Test
    public void test() {
        target.method();
    }
}

2：配置文件+注解两掺
Spring核心配置文件applicationContext.xml配置

	<!--开启包扫描-->
    <context:component-scan base-package="xxx.xxx"></context:component-scan>
    <!--开启aop自动代理-->
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>

通知/增强类

@Component
@Aspect
public class MyAspect {
    //增强方法
    @Before("execution(* xxx.xxx.target.impl.*.*(..))")
    public void before() {
        System.out.println("before running.......");
    }
}

目标类(需要增强的类)

@Component
public class TargetImpl implements Target {
    //切点
    public void method() {
        System.out.println(" target running.......");
    }
}

测试类

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class SpringTest {
    @Autowired
    private Target target;
    @Test
    public void test() {
        target.method();
    }
}

3纯注解
配置类

@Configuration
@ComponentScan("xxx.xxx")
public class SpringConfig {
}

通知/增强类

@Component
@Aspect
public class MyAspect {
    //增强方法
    @Before("execution(* xxx.xxx.target.impl.*.*(..))")
    public void before() {
        System.out.println("before running.......");
    }
}

目标类(需要增强的类)

@Component
public class TargetImpl implements Target {
    //切点
    public void method() {
        System.out.println(" target running.......");
    }
}

测试类

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {SpringConfig.class})
@EnableAspectJAutoProxy
public class SpringTest {
    @Autowired
    private Target target;
    @Test
    public void test() {
        target.method();
    }
}

如文中有不合理之处，请各位批评指正。