log4j custom jdbc appender with spring dependency injected datasource

Question

I am trying to add custom appender by extending JDBC appender to store my log data in to database. But i need to override the database connection from spring injected dataSource. Its not working for me because log4j context is loading first and spring context is not yet initialized.So i am getting Null Pointer Exception for Spring injected DataSource.

I am completely novice to the spring. Please provide me an example if possible.

**This is how my Spring configuration looks like..**    

 <!-- DataSource -->
<bean id="dataSource" class="*******" destroy-method="close"
    p:driverClassName="XXXXX" 
    p:url="jdbc:oracle://****"
    p:username="root"
    p:password="password"/>

<!-- Hibernate session factory -->
<bean id="sessionFactory"
    class="org.springframework.orm.hibernate4.annotation.AnnotationSessionFactoryBean"
    p:dataSource-ref="dataSource">
    <property name="packagesToScan" value="com.beans"/>
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
            <prop key="hibernate.show_sql">true</prop>
            <prop key="hibernate.transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</prop>
        </props>
    </property>
</bean> 

<!-- Transaction Manager -->
<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
       <property name="sessionFactory">        <ref bean="sessionFactory" />
</property>




My log4j Configuration



<appender name="SMTT-JDBC" class="com.XXX.XXX.CustomAppender">  
                <errorHandler class="org.apache.log4j.varia.FallbackErrorHandler">  
                        <appender-ref ref="FILE"/>  
                </errorHandler>  
                <param name="Threshold" value="INFO"/>     
                <layout class="org.apache.log4j.PatternLayout">  
                        <param name="ConversionPattern"  
                                value="INSERT INTO LOGS VALUES ('%x', current_timestamp ,'%C','%p','%m')" />  
                </layout>  
   </appender>  


This is how my Custom Appender looks like:



public class CustomJDBCAppender extends org.apache.log4j.jdbc.JDBCAppender {

 protected java.sql.Connection getConnection() throws java.sql.SQLException
   {

        /* I need to get Connection From Spring configuration */

     }

     protected void closeConnection() throws java.sql.SQLException {
             if (connection != null && !connection.isClosed())
                   connection.close();
     }
}



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