Question

I’m writing a java application with Spring 3.It’s working well with xml,but not working at all in annotation.

here’s my snippet:

@Service("oracleDB")
public class OracleDatabase implements IDatabase
{
     @Value("oracle.jdbc.driver.OracleDriver") 
     private String driverName;
     @Value("jdbc:oracle:thin:@")
     private String url;

     public String getDriverName()
     {
          return driverName;
     }
 }

My ApplicationContext.xml is like this:

<?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:context="http://www.springframework.org/schema/context"
 xsi:schemaLocation="
 http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
 http://www.springframework.org/schema/context   http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <context:annotation-config />

    <context:component-scan 
        base-package="com.pdiwt.database"></context:component-scan>
        </beans>

MyInvoker is like that:

public class MyInvoker{
   public static void main(String args[]){
        XmlBeanFactory beanFactory = new XmlBeanFactory(new ClassPathResource("applicationContext.xml"));
        OracleDatabase oracelDB = beanFactory.getBean("oracleDB");
        System.out.println(oracleDB.getDriverName());
   }
}

guess what? The result is null. Is there anything wrong?

Answer 1

The problem here is using xmlbeanfactory, which is a common mistake. Try this instead, it will work perfectly:

ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");
OracleDatabase oracleDB = (OracleDatabase)context.getBean("oracleDB");
...

I think the beanfactory is simply not powerful enough to handle the @Value annotations. More information can be found here.