Add AspectJ in Webservice

Question

i have a Java EE Webservice (REST) and would now like to use AspectJ, to create a rule that will print-out every incoming service call and their params.

I just read this tutorial and implemented the following code:

POM.XML

        <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjrt</artifactId>
        <version>1.8.10</version>
    </dependency>
    
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.8.10</version>
    </dependency>
    
</dependencies>
<build>
  <plugins>
    <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>aspectj-maven-plugin</artifactId>
        <version>1.7</version>
        <configuration>
            <complianceLevel>1.8</complianceLevel>
            <source>1.8</source>
            <target>1.8</target>
            <showWeaveInfo>true</showWeaveInfo>
            <verbose>true</verbose>
            <Xlint>ignore</Xlint>
            <encoding>UTF-8 </encoding>
        </configuration>
        <executions>
            <execution>
                <goals>
                    <!-- use this goal to weave all your main classes -->
                    <goal>compile</goal>
                    <!-- use this goal to weave all your test classes -->
                    <goal>test-compile</goal>
                </goals>
            </execution>
        </executions>
    </plugin>
</plugins>

...and created a Test.aj File, with a Pointcut which should print-out a teststring after calling the getSignOfLife():

import de.jack.businesspartner.service.BusinessPartnerServiceImpl;
public aspect TestAspectJ {

    pointcut getSignOfLife() : 
      call(void BusinessPartnerServiceImpl.getSignOfLife());

    before() : getSignOfLife() {
        System.err.println("ADKL TEST ASPECT");
    }

}

--> But nothing happens if i call the getSignOfLife() Method. Can you help me?

Do you run your app from an IDE or you create a .war file and deploy it to some app server/ servlet container? — Babl, May 15 '17 at 08:29
I created a .war file with my IDE and deployed this to my wildfly application server. But the aspect dont get called if i call the getSignOfLife() method... — goblingift, May 15 '17 at 15:22
Give a try for this tutorial: https://www.mkyong.com/spring3/spring-aop-aspectj-annotation-example/ — yılmaz, May 16 '17 at 10:35
You are using `System.err` for output. Make sure it (stderr) is not redirected elsewhere, like a file. — Janith Jeewantha, May 19 '17 at 06:25

Tony · Answer 1 · 2017-05-19T14:07:06.080

Your point cut expression may be wrong:

pointcut getSignOfLife() : 
  call(void BusinessPartnerServiceImpl.getSignOfLife());

The expression in call should match the signature of your real method.

CheckList

return type: getSignOfLife seems has a return value, which you write a void return type in expression, which will fails the match;
parameter type: you can use f(..) to represent a method f with any parameter, but if you left it empty, it means no parameter. If your actual method has parameter, it will fails the match;
notice that int and Integer is different in expression, because primitives and boxing type is different;

you need original compiler plugin of maven in your pom;

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
            <source>1.8</source>
            <target>1.8</target>
            <encoding>UTF-8</encoding>
        </configuration>
    </plugin>

More

You may refer to here if you want to dive into AspectJ
In the most common cases, Spring AOP is enough to handle jobs like logging, auth etc, which can be used with annotation and I think, is more convenient.
Runnable code.

Adonis · Accepted Answer · 2017-05-19T11:16:31.820

@Tony explained it pretty well.

Just regarding the tutorial you pointed out, I tested it by modifying slightly the account aspect:

public aspect AccountAspect {
    final int MIN_BALANCE = 10;

    pointcut callWithDraw(int amount, Account acc) : 
     call(boolean Account.withdraw(int)) && args(amount) && target(acc);

    before(int amount, Account acc) : callWithDraw(amount, acc) {
    }

    boolean around(int amount, Account acc) : 
      callWithDraw(amount, acc) {
        acc.balance -= 5;
        if (acc.balance < amount) {
            return false;
        }
        return proceed(amount, acc);
    }

    after(int amount, Account balance) : callWithDraw(amount, balance) {
        System.out.println("After withdraw " + amount);
    }
}

Then in a simple servlet:

@WebServlet("/Hello")
public class Hello extends HttpServlet {

    /**
     * 
     */
    private static final long serialVersionUID = 482093033327453159L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        Account acc = new Account();
        resp.setContentType("text/html");
        PrintWriter out = resp.getWriter();
        out.println("Account before withdraw: " + acc.balance + "<br/>");
        acc.withdraw(10);
        out.println("Account after withdraw: " + acc.balance + "");
        out.close();
    }
}

I used:

Java 8
Wildfly 10.1.0.Final

It works as expected (when calling withdraw the account is withdrawn of 5 more, as you can see from the around in my aspectj file, and prints are written on the console)

Add AspectJ in Webservice

2 Answers2

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