Simple example for Before advice and After Advice in Spring Framework

BeforeAdvice and AfterReturningAdvice

This tips presents a very simple program for invoking the Before Advice and After Returning Advice in the Spring Framework. Thsese two methods are part of Spring’s AOP implementation and used as interceptor methods. the following program create spring beans using the standalone java program and invokes the business logic method.
Business logic method is surrounded by Before Advice and After Returning Advice method. It is configured in thespring’s configuration xml file. When ever any client invokes that particular method, the advices will be called to perform a certain operations. Normally these kind of techniques used for printing the debug messages while invoking the methods.

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SpringAopMain.java

package javabeat.net.spring.aop;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;

/**
 * source : www.javabeat.net
 */
public class SpringAopMain {
    public static void main(String[] args) {
        // Read the configuration file
        ApplicationContext ctx = new FileSystemXmlApplicationContext(
                "spring-config.xml");

        // Instantiate an object
        BusinessInterface businessInterface = (BusinessInterface) ctx
                .getBean("businesslogicbean");

        // Execute the public method of the bean
        businessInterface.businessLogicMethod();
    }
}

BusinessInterface.java

package javabeat.net.spring.aop;

/**
 * source : www.javabeat.net
 */
public interface BusinessInterface {
    void businessLogicMethod();
}

BusinessInterfaceImpl.java

package javabeat.net.spring.aop;

/**
 * source : www.javabeat.net
 */
public class BusinessInterfaceImpl implements BusinessInterface{
    public void businessLogicMethod() {
        System.out.println("BusinessLogic Method Called");
    }
}

BeforeAdviceExample.java

package javabeat.net.spring.aop;
import java.lang.reflect.Method;

import org.springframework.aop.MethodBeforeAdvice;

/**
 * source : www.javabeat.net
 */
public class BeforeAdviceExample implements MethodBeforeAdvice {
    public void before(Method arg0, Object[] arg1, Object arg2)
            throws Throwable {
        System.out.println("Before Advice Called");
    }
}

AfterAdviceExample.java

package javabeat.net.spring.aop;

import java.lang.reflect.Method;

import org.springframework.aop.AfterReturningAdvice;

/**
 * source : www.javabeat.net
 */
public class AfterAdviceExample implements AfterReturningAdvice {
    public void afterReturning(Object arg0, Method arg1, Object[] arg2,
            Object arg3) throws Throwable {
        System.out.println("After Advice Called");
    }
}

spring-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC
    "-//SPRING//DTD BEAN//EN"
    "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>

    <!-- Bean configuration -->
    <bean id="businesslogicbean"
        class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="proxyInterfaces">
            <value>javabeat.net.spring.aop.BusinessInterface</value>
        </property>
        <property name="target">
            <ref local="beanTarget" />
        </property>
        <property name="interceptorNames">
            <list>
                <value>theTracingBeforeAdvisor</value>
                <value>theTracingAfterAdvisor</value>
            </list>
        </property>
    </bean>

    <!-- Bean Classes -->
    <bean id="beanTarget" class="javabeat.net.spring.aop.BusinessInterfaceImpl" />

    <!-- Advisor pointcut definition for before advice -->
    <bean id="theTracingBeforeAdvisor"
        class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
        <property name="advice">
            <ref local="theTracingBeforeAdvice" />
        </property>
        <property name="pattern">
            <value>.*</value>
        </property>
    </bean>

    <!-- Advisor pointcut definition for before advice -->
    <bean id="theTracingAfterAdvisor"
        class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
        <property name="advice">
            <ref local="theTracingAfterAdvice" />
        </property>
        <property name="pattern">
            <value>.*</value>
        </property>
    </bean>

    <!-- Advice classes -->
    <bean id="theTracingBeforeAdvice"
        class="javabeat.net.spring.aop.BeforeAdviceExample" />
    <bean id="theTracingAfterAdvice"
        class="javabeat.net.spring.aop.AfterAdviceExample" />

</beans>

also read:

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Introduction to Spring Framework

Introduction to Spring MVC Framework