log4j2 JDBCAppender with Spring

Question

I have already defined a datasource in Spring configuration.

<bean id="dataSource"
    class="org.springframework.jdbc.datasource.DriverManagerDataSource">

    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://localhost:3306/db" />
    <property name="username" value="root" />
    <property name="password" value="password" />
</bean>

For LOG4J2 JDBCAppender, I know we need to obtain the datasource:

 <JDBC name="databaseAppender" tableName="error_log">
        <ConnectionFactory class="net.example.db"
            method="getDatabaseConnection" />
        <Column name="EVENT_DATE" isEventTimestamp="true" />
        <Column name="LEVEL" pattern="%level" />
        <Column name="LOGGER" pattern="%logger" />
        <Column name="MESSAGE" pattern="%message" />
        <Column name="THROWABLE" pattern="%ex{full}" />
    </JDBC>

I have already added the package into the component-scan:

<context:component-scan base-package="com.test,net.example.db" />

And add annotation at the class ConnectionFactory as a Component

import java.sql.Connection;
import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class ConnectionFactory {

    @Autowired
    private DataSource dataSource;

    public void setDataSource(DataSource dataSource) {
        this.dataSource = dataSource;
    }

    public Connection getDatabaseConnection() throws Exception {
        return dataSource.getConnection();
    }

}

However, I am getting null when call getDatabaseConnection()

2017-01-14 14:17:24,579 localhost-startStop-1 ERROR JdbcDatabaseManager jdbcManager{ description=databaseAppender, bufferSize=0, connectionSource=factory{ public static java.sql.Connection net.example.db.ConnectionFactory.getDatabaseConnection() }, tableName=error_log, columns=[ { name=EVENT_DATE, layout=null, literal=null, timestamp=true }, { name=LEVEL, layout=%level, literal=null, timestamp=false }, { name=LOGGER, layout=%logger, literal=null, timestamp=false }, { name=MESSAGE, layout=%message, literal=null, timestamp=false }, { name=THROWABLE, layout=%ex{full}, literal=null, timestamp=false } ] } Could not perform database startup operations: java.sql.SQLException: Failed to obtain connection from factory method. java.sql.SQLException: Failed to obtain connection from factory method.
    at org.apache.logging.log4j.core.appender.db.jdbc.FactoryMethodConnectionSource$1.getConnection(FactoryMethodConnectionSource.java:107)
    at org.apache.logging.log4j.core.appender.db.jdbc.FactoryMethodConnectionSource.getConnection(FactoryMethodConnectionSource.java:53)
    at org.apache.logging.log4j.core.appender.db.jdbc.JdbcDatabaseManager.startupInternal(JdbcDatabaseManager.java:60)
    at org.apache.logging.log4j.core.appender.db.AbstractDatabaseManager.startup(AbstractDatabaseManager.java:65)
    at org.apache.logging.log4j.core.appender.db.AbstractDatabaseAppender.start(AbstractDatabaseAppender.java:89)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:255)
    at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:530)
    at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:258)
    at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:239)
    at org.apache.logging.log4j.core.config.Configurator.initialize(Configurator.java:158)
    at org.apache.logging.log4j.web.Log4jWebInitializerImpl.initializeNonJndi(Log4jWebInitializerImpl.java:168)
    at org.apache.logging.log4j.web.Log4jWebInitializerImpl.start(Log4jWebInitializerImpl.java:110)
    at org.apache.logging.log4j.web.Log4jServletContainerInitializer.onStartup(Log4jServletContainerInitializer.java:57)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5604)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1571)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1561)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.apache.logging.log4j.core.appender.db.jdbc.FactoryMethodConnectionSource$1.getConnection(FactoryMethodConnectionSource.java:105)
    ... 20 more

I am skeptical that whether the bean dataSource has not yet created when LOGJ2 calls getDatabaseConnection(). Please let me know what would be the reason and solution.

Answer 1

Finally I found one solution to my answer. LOG4J is initialized before Spring, therefore the bean Datasource will return null.

I followed the instructions from below URL: How to use Spring BoneCPDataSource bean as data source for Log4j 2 JDBC appender?

And everything is fine now.

Answer 2

Please go through this tutorial [ Log4j2 JDBC ] (http://self-learning-java-tutorial.blogspot.in/2015/10/log4j2-jdbcappender-write-log-messages.html)

As mentioned : please see this part

Following are the ConnectionFactory Parameters.

Class : Name of the class, that contains a static factory method for obtaining JDBC connections.
method : The name of a static factory method for obtaining JDBC connections. Method return type must be either java.sql.Connection or DataSource.

Please note that it requires a static factory method. thats why invocation of reflection fails.