Spring AOP - XML Based Application

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In this chapter, we will write actual AOP applications using Spring AOP Framework. Before you start writing your first example using Spring-WS framework, you have to make sure that you have set up your Spring AOP environment properly as explained in Spring Web Services - Environment Setup chapter.

Now, proceed to write a simple console-ased Spring AOP Application, which will demonstrate AOP concepts.

Create a Project

Step 1 − Open a command console, go the C:\MVN directory and execute the following mvn command.

C:\MVN>mvn archetype:generate -DgroupId = com.howcodex -DartifactId = Student
	-DarchetypeArtifactId = maven-archetype-quickstart -DinteractiveMode = false

Maven will start processing and will create the complete Java application project structure.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> maven-archetype-plugin:2.4:generate (default-cli) > generate-sources
@ standalone-pom >>>
[INFO]
[INFO] <<< maven-archetype-plugin:2.4:generate (default-cli) < generate-sources
@ standalone-pom <<<
[INFO]
[INFO] --- maven-archetype-plugin:2.4:generate (default-cli) @ standalone-pom --
-
[INFO] Generating project in Batch mode
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/ma
ven-archetype-quickstart/1.0/maven-archetype-quickstart-1.0.jar
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/mav
en-archetype-quickstart/1.0/maven-archetype-quickstart-1.0.jar (5 KB at 1.1 KB/s
ec)
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/ma
ven-archetype-quickstart/1.0/maven-archetype-quickstart-1.0.pom
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/mav
en-archetype-quickstart/1.0/maven-archetype-quickstart-1.0.pom (703 B at 1.2 KB/
sec)
[INFO] -------------------------------------------------------------------------
---
[INFO] Using following parameters for creating project from Old (1.x) Archetype:
 maven-archetype-quickstart:1.0
[INFO] -------------------------------------------------------------------------
---
[INFO] Parameter: groupId, Value: com.howcodex
[INFO] Parameter: packageName, Value: com.howcodex
[INFO] Parameter: package, Value: com.howcodex
[INFO] Parameter: artifactId, Value: Student
[INFO] Parameter: basedir, Value: C:\MVN
[INFO] Parameter: version, Value: 1.0-SNAPSHOT
[INFO] project created from Old (1.x) Archetype in dir: C:\MVN\Student
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:17 min
[INFO] Finished at: 2017-02-19T21:11:14+05:30
[INFO] Final Memory: 15M/114M
[INFO] ------------------------------------------------------------------------

Step 2 − Go to C:/MVN directory. You'll see a Java application project created, named student (as specified in artifactId). Update the POM.xml to include Spring-AOP dependencies. Add MainApp.java, Student.java, and Logging.java files.

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/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.howcodex</groupId>
   <artifactId>Student</artifactId>
   <packaging>jar</packaging>
   <version>1.0-SNAPSHOT</version>
   <name>Student</name>
   <url>http://maven.apache.org</url>
   
   <dependencies>
      <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
         <version>3.8.1</version>
         <scope>test</scope>
      </dependency>
      
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-aop</artifactId>
         <version>4.1.0.RELEASE</version>
      </dependency>
      
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-context</artifactId>
         <version>4.1.4.RELEASE</version>
      </dependency>
      
      <dependency>
         <groupId>org.aspectj</groupId>
         <artifactId>aspectjweaver</artifactId>
         <version>1.6.8</version>
      </dependency>
      
   </dependencies>
</project>
package com.howcodex;

public class Logging {

   /** 
    * This is the method which I would like to execute
    * before a selected method execution.
    */
   public void beforeAdvice() {
      System.out.println("Going to setup student profile.");
   }

   /** 
    * This is the method which I would like to execute
    * after a selected method execution.
    */
   public void afterAdvice() {
      System.out.println("Student profile has been setup.");
   }

   /** 
    * This is the method which I would like to execute
    * when any method returns.
    */
   public void afterReturningAdvice(Object retVal){
      System.out.println("Returning:" + retVal.toString() );
   }

   /**
    * This is the method which I would like to execute
    * if there is an exception raised.
    */
   public void AfterThrowingAdvice(IllegalArgumentException ex) {
      System.out.println("There has been an exception: " + ex.toString());   
   }
   
}

Following is the content of the Student.java file.

package com.howcodex;

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();
   }
}

Following is the content of the MainApp.java file.

package com.howcodex;

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

public class MainApp {
   public static void main(String[] args) {
      ApplicationContext context = 
         new ClassPathXmlApplicationContext("Beans.xml");

      Student student = (Student) context.getBean("student");

      student.getName();
      student.getAge();
      
      student.printThrowException();
   }
}

Step 3 − Add the configuration file Beans.xml under src > main > resources folder.

<?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-3.0.xsd 
   http://www.springframework.org/schema/aop 
   http://www.springframework.org/schema/aop/spring-aop-3.0.xsd ">

   <aop:config>
      <aop:aspect id = "log" ref = "logging">
         <aop:PointCut id = "selectAll" 
            expression = "execution(* com.howcodex.*.*(..))"/>
         <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>

   <!-- Definition for student bean -->
   <bean id = "student" class = "com.howcodex.Student">
      <property name = "name"  value = "Zara" />
      <property name = "age"  value = "11"/>      
   </bean>

   <!-- Definition for logging aspect -->
   <bean id = "logging" class = "com.howcodex.Logging"/> 
      
</beans>

Step 4 − Open the command console, go the C:\MVN directory and execute the following mvn command.

C:\MVN>Student> mvn package

Maven will start processing and downloading the required libraries.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Student 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven
-jar-plugin/2.4/maven-jar-plugin-2.4.pom
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-
jar-plugin/2.4/maven-jar-plugin-2.4.pom (6 KB at 2.2 KB/sec)
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven
-jar-plugin/2.4/maven-jar-plugin-2.4.jar
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-
jar-plugin/2.4/maven-jar-plugin-2.4.jar (34 KB at 31.6 KB/sec)
Downloading: https://repo.maven.apache.org/maven2/org/springframework/spring-aop
/4.1.0.RELEASE/spring-aop-4.1.0.RELEASE.pom
Downloaded: https://repo.maven.apache.org/maven2/org/springframework/spring-aop/
4.1.0.RELEASE/spring-aop-4.1.0.RELEASE.pom (3 KB at 3.7 KB/sec)
Downloading: https://repo.maven.apache.org/maven2/org/springframework/spring-bea
ns/4.1.0.RELEASE/spring-beans-4.1.0.RELEASE.pom
Downloaded: https://repo.maven.apache.org/maven2/org/springframework/spring-bean
s/4.1.0.RELEASE/spring-beans-4.1.0.RELEASE.pom (3 KB at 4.1 KB/sec)
Downloading: https://repo.maven.apache.org/maven2/org/springframework/spring-cor
e/4.1.0.RELEASE/spring-core-4.1.0.RELEASE.pom
Downloaded: https://repo.maven.apache.org/maven2/org/springframework/spring-core
/4.1.0.RELEASE/spring-core-4.1.0.RELEASE.pom (3 KB at 4.0 KB/sec)
Downloading: https://repo.maven.apache.org/maven2/org/springframework/spring-aop
/4.1.0.RELEASE/spring-aop-4.1.0.RELEASE.jar
Downloading: https://repo.maven.apache.org/maven2/org/springframework/spring-cor
e/4.1.0.RELEASE/spring-core-4.1.0.RELEASE.jar
Downloading: https://repo.maven.apache.org/maven2/org/springframework/spring-bea
ns/4.1.0.RELEASE/spring-beans-4.1.0.RELEASE.jar
Downloaded: https://repo.maven.apache.org/maven2/org/springframework/spring-aop/
4.1.0.RELEASE/spring-aop-4.1.0.RELEASE.jar (351 KB at 43.9 KB/sec)
Downloaded: https://repo.maven.apache.org/maven2/org/springframework/spring-bean
s/4.1.0.RELEASE/spring-beans-4.1.0.RELEASE.jar (685 KB at 37.5 KB/sec)
Downloaded: https://repo.maven.apache.org/maven2/org/springframework/spring-core
/4.1.0.RELEASE/spring-core-4.1.0.RELEASE.jar (982 KB at 47.1 KB/sec)
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ Student --
-
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\Student\src\main\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ Student ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. b
uild is platform dependent!
[INFO] Compiling 1 source file to C:\MVN\Student\target\classes
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ St
udent ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\Student\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ Student
 ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. b
uild is platform dependent!
[INFO] Compiling 1 source file to C:\MVN\Student\target\test-classes
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ Student ---
[INFO] Surefire report directory: C:\MVN\Student\target\surefire-reports
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/surefire/sure
fire-junit3/2.12.4/surefire-junit3-2.12.4.pom
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/surefire/suref
ire-junit3/2.12.4/surefire-junit3-2.12.4.pom (2 KB at 1.3 KB/sec)
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/surefire/sure
fire-junit3/2.12.4/surefire-junit3-2.12.4.jar
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/surefire/suref
ire-junit3/2.12.4/surefire-junit3-2.12.4.jar (26 KB at 27.7 KB/sec)

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.howcodex.AppTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.002 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ Student ---
Downloading: https://repo.maven.apache.org/maven2/classworlds/classworlds/1.1-al
pha-2/classworlds-1.1-alpha-2.jar
Downloaded: https://repo.maven.apache.org/maven2/classworlds/classworlds/1.1-alp
ha-2/classworlds-1.1-alpha-2.jar (37 KB at 35.8 KB/sec)
[INFO] Building jar: C:\MVN\Student\target\Student-1.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 38.441 s
[INFO] Finished at: 2017-02-19T21:18:59+05:30
[INFO] Final Memory: 18M/109M
[INFO] ------------------------------------------------------------------------

Import Project in Eclipse

Step 1 − Open Eclipse.

Step 2 − Select File → Import → option.

Step 3 − Select Maven Projects Option. Click the Next Button.

Step 4 − Select Project location, where Student project was created using Maven.

Step 5 − Click Finish Button.

Run Project

Once you are done creating the source and configuration files, run your application. Rightclick on MainApp.java in your application and use run as Java Application command. If everything is fine with your application, it will print the following message.

Going to setup student profile.
Name : Zara
Student profile has been setup.
Returning:Zara
Going to setup student profile.
Age : 11
Student profile has been setup.
Returning:11
Going to setup student profile.
Exception raised
Student profile has been setup.
There has been an exception: java.lang.IllegalArgumentException
Exception in thread "main" java.lang.IllegalArgumentException
   at com.howcodex.Student.printThrowException(Student.java:25)
   
   at com.howcodex.Student$$FastClassBySpringCGLIB$$7dc55815.invoke(<generated>)
   
   at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
   
   at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:717)
   
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
   
   at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:52)
   
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
   
   at org.springframework.aop.aspectj.AspectJAfterAdvice.invoke(AspectJAfterAdvice.java:43)
   
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
   
   at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:52)
   
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
   
   at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:58)
   
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
   
   at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
   
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
   
   at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653)
   
   at com.howcodex.Student$$EnhancerBySpringCGLIB$$56a970f2.printThrowException(<generated>)
   
   at com.howcodex.MainApp.main(MainApp.java:16)
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