Spring中基于AOP的XML架构

以下内容引用自http://wiki.jikexueyuan.com/project/spring/aop-with-spring-framenwork/xml-schema-based-aop-with-spring.html：

为了使用aop命名空间标签，需要导入spring-aop架构，如下所示：

<?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: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/aop
                        http://www.springframework.org/schema/aop/spring-aop.xsd">

</beans>

还需要增加而外的jar包用于支持AspectJ：

    <!-- aspectjrt.jar -->
    <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjrt -->
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjrt</artifactId>
        <version>1.8.10</version>
    </dependency>

    <!-- aspectjweaver.jar -->
    <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.8.10</version>
    </dependency>

集成步骤：

1、声明一个aspect（方面）

一个aspect是使用<aop:aspect>元素声明的，并使用ref属性引用bean，如下所示：

<aop:config>
   <aop:aspect id="myAspect" ref="aBean">
      ...
   </aop:aspect>
</aop:config>

<bean id="aBean" class="...">
   ...
</bean>

这个“aBean”将被配置和依赖注入就像其他Spring bean一样。

2、声明一个pointcut（切入点）

切入点有助于确定用不同建议执行的关联点（即方法）。在使用基于XML Schema的配置时，切入点将定义如下：

<aop:config>
   <aop:aspect id="myAspect" ref="aBean">
   　　<aop:pointcut id="businessService" expression="execution(* com.xyz.myapp.service.*.*(..))"/>
   　　...
   </aop:aspect>
</aop:config>
<bean id="aBean" class="...">
　　...
</bean>

以下示例定义了一个名为“businessService”的切入点，该切入点将匹配在com.tutorialspoint包中的Student类中可用的getName()方法：

<aop:config>
   <aop:aspect id="myAspect" ref="aBean">
   　　<aop:pointcut id="businessService" expression="execution(*com.tutorialspoint.Student.getName(..))"/>
   　　...
   </aop:aspect>
</aop:config>

<bean id="aBean" class="...">
   ...
</bean>

提示：

①类似：“execution(*com.tutorialspoint.Student.getName(..))”这样的语法叫做AspectJ切入点语法，参考：http://www.cnblogs.com/EasonJim/p/6901806.html

②官方文档关于AspectJ的介绍：https://docs.spring.io/spring/docs/current/spring-framework-reference/html/aop.html#aop-ataspectj

3、声明建议（通知类型）

可以使用<aop：{ADVICE NAME}>五个建议中的任何一个元素在<aop：aspect>内声明，如下所示：

<aop:config>
   <aop:aspect id="myAspect" ref="aBean">
      <aop:pointcut id="businessService" expression="execution(* com.xyz.myapp.service.*.*(..))"/>

      <!-- a before advice definition -->
      <aop:before pointcut-ref="businessService" method="doRequiredTask"/>

      <!-- an after advice definition -->
      <aop:after pointcut-ref="businessService" method="doRequiredTask"/>

      <!-- an after-returning advice definition -->
      <!--The doRequiredTask method must have parameter named retVal -->
      <aop:after-returning pointcut-ref="businessService" returning="retVal" method="doRequiredTask"/>

      <!-- an after-throwing advice definition -->
      <!--The doRequiredTask method must have parameter named ex -->
      <aop:after-throwing pointcut-ref="businessService" throwing="ex" method="doRequiredTask"/>

      <!-- an around advice definition -->
      <aop:around pointcut-ref="businessService" method="doRequiredTask"/>
      
　　　 ...
   </aop:aspect>
</aop:config>

<bean id="aBean" class="...">
  ...
</bean>

可以对不同的建议使用相同的doRequiredTask或不同的方法。这些方法将被定义为方面模块的一部分。

至此集成完毕。

基于AOP的XML架构的示例：

pom.xml：

<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>

  <groupId>com.jsoft.testspring</groupId>
  <artifactId>testaopxml</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>testaopxml</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>

    <!-- Spring Core -->
    <!-- http://mvnrepository.com/artifact/org.springframework/spring-core -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>4.1.4.RELEASE</version>
    </dependency>

    <!-- Spring Context -->
    <!-- http://mvnrepository.com/artifact/org.springframework/spring-context -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>4.1.4.RELEASE</version>
    </dependency>

    <!-- String AOP -->
    <!-- http://mvnrepository.com/artifact/org.springframework/spring-aop -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>4.1.4.RELEASE</version>
    </dependency>

    <!-- aspectjrt.jar -->
    <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjrt -->
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjrt</artifactId>
        <version>1.8.10</version>
    </dependency>

    <!-- aspectjweaver.jar -->
    <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.8.10</version>
    </dependency>

  </dependencies>
</project>

Logging.java：

package com.jsoft.testspring.testaopxml;

public class Logging {

    public void beforeAdvice() {
        System.out.println("Going to setup student profile.");
    }

    public void afterAdvice() {
        System.out.println("Student profile has been setup.");
    }

    public void afterReturningAdvice(Object retVal) {
        System.out.println("Returning:" + retVal.toString());
    }

    public void AfterThrowingAdvice(IllegalArgumentException ex) {
        System.out.println("There has been an exception: " + ex.toString());
    }
}

Student.java：

package com.jsoft.testspring.testaopxml;

public class Student {
    private Integer age;
    private String name;

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getAge() {
        System.out.println("Age : " + age);
        return age;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        System.out.println("Name : " + name);
        return name;
    }

    public void printThrowException() {
        System.out.println("Exception raised:");
        throw new IllegalArgumentException();
    }
}

beans.xml：

<?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: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/aop
                        http://www.springframework.org/schema/aop/spring-aop.xsd">

   <aop:config>
      <aop:aspect id="log" ref="logging">
         <aop:pointcut id="selectAll" expression="execution(* com.jsoft..*.*(..))"/>
         <aop:before pointcut-ref="selectAll" method="beforeAdvice"/>
         <aop:after pointcut-ref="selectAll" method="afterAdvice"/>
         <aop:after-returning pointcut-ref="selectAll" returning="retVal" method="afterReturningAdvice"/>
         <aop:after-throwing pointcut-ref="selectAll" throwing="ex" method="AfterThrowingAdvice"/>
      </aop:aspect>
   </aop:config>

   <bean id="student" class="com.jsoft.testspring.testaopxml.Student">
      <property name="name"  value="Zara" />
      <property name="age"  value="11"/>
   </bean>

   <bean id="logging" class="com.jsoft.testspring.testaopxml.Logging"/> 

</beans>

App.java：

package com.jsoft.testspring.testaopxml;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * Hello world!
 *
 */
public class App
{
    public static void main( String[] args )
    {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
         Student student = (Student) context.getBean("student");
         student.getName();
         student.getAge();
         student.printThrowException();
    }
}

测试结果：

测试工程：https://github.com/easonjim/5_java_example/tree/master/springtest/test16/testaopxml