Spring AOP — Throwing Advice | Code Factory

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• ThrowsAdvice example using Programmatic approach.
• ThrowsAdvice: Throws Advice it is executed if actual method throws exception.

Create Java Project

• Open Eclipse
• Go to File -> New -> Other… -> Java Project
• Create AOP-Programmatic4 project
• Right click on project -> Build Path -> Configure Build Path -> Libraries tab -> Add External JARs
  - aopalliance.jar
  - aspectjrt.jar
  - aspectjweaver.jar
  - cglib-nodep-X.X.jar
  - commons-logging-X.X.jar
  - spring-aop-X.X.X.jar
  - spring-beans-X.X.X.jar
  - spring-context-X.X.X.jar
  - spring-core-X.X.X.jar
  - aspectjlib-X.X.X.jar
  - spring-aspects-X.X.X.jar
• * You can find dtd information from spring-beans-X.X.X.jar -> org -> springframework -> beans -> factory -> xml -> spring-beans.dtd (line no 36 & 37)

Bank.java

package com.codeFactory.business;
/**
 * @author code.factory
 *
 */
public class Bank {
	private int amount = 1000;
	private String accNo = "SBI12345";
	public int deposit(int amount, String accNo) {
		if (accNo.equals(this.accNo)) {
			this.amount += amount;
		} else {
			throw new AccnoNotFoundException();
		}
		return this.amount;
	}
	@Override
	public String toString() {
		return "Bank [amount=" + amount + ", accNo=" + accNo + "]";
	}
}

LogExceptionService.java

package com.codeFactory.service;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.aop.ThrowsAdvice;
import com.codeFactory.business.Bank;
/**
 * @author code.factory
 *
 */
public class LogExceptionService implements ThrowsAdvice {
	/* ThrowsAdvice will not force to implement any method
	 * It is a Marker Interace */
	
	public void afterThrowing(Exception e) {
		Log l = LogFactory.getLog(Bank.class);
		l.info("incase of exception in deposit: " + e);
	}
}

AccnoNotFoundException.java

package com.codeFactory.business;
/**
 * @author code.factory
 *
 */
public class AccnoNotFoundException extends RuntimeException {
	@Override
	public String toString() {
		return "AccNo invalid";
	}
}

Client.java

package com.codeFactory.test;
import org.springframework.aop.framework.ProxyFactoryBean;
import com.codeFactory.business.Bank;
import com.codeFactory.service.LogExceptionService;
/**
 * @author code.factory
 *
 */
public class Client {
	public static void main(String... args) {
		/* create target */
		Bank b = new Bank();
		/* create advice */
		LogExceptionService les = new LogExceptionService();
		/* add target + advice to proxy */
		ProxyFactoryBean bean = new ProxyFactoryBean();
		bean.setTarget(b);
		bean.addAdvice(les);
		
		/* get generated proxy object */
		Bank bankProxy = (Bank) bean.getObject();
		int amt = bankProxy.deposit(150, "SBI12345");
		System.out.println(amt);
		
		amt = bankProxy.deposit(150, "SBI1234");
		System.out.println(amt);
		
	}
}

Output:

1150
Dec 23, 2020 1:19:28 PM com.codeFactory.service.LogExceptionService afterThrowing
INFO: incase of exception in deposit: AccNo invalid
Exception in thread "main" AccNo invalid
	at com.codeFactory.business.Bank.deposit(Bank.java:16)
	at com.codeFactory.business.Bank$$FastClassByCGLIB$$1a9c7cc.invoke(<generated>)
	...
	...
	at com.codeFactory.business.Bank$$EnhancerByCGLIB$$99d62c76.deposit(<generated>)
	at com.codeFactory.test.Client.main(Client.java:28)