带有 Spring 的 log4j2 JDBC appender

Question

Log4j2 JDBC appender can be setup using a pooled connection factory that is defined using calls and method (see log4j2 Appenders ):

 <ConnectionFactory class="net.example.db.ConnectionFactory" method="getDatabaseConnection" />

Using Spring I have already a defined datasource that is providing a pooled connection :

<bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="${db_driver_class}" />
    <property name="url" value="${db_jdbc_url}" />
    <property name="username" value="${db_username}" />
    <property name="password" value="${db_password}" />
    <property name="initialSize" value="10" />
    <property name="maxActive" value="100" />
    <property name="maxIdle" value="50" />
    <property name="minIdle" value="10" />
    <property name="validationQuery" value="select 1" />
    <property name="testOnBorrow" value="true" />

I would like to use the the Spring connection pool for the JDBC appender. Any idea how can this be done ?

thanks

Raz

Answer 1

I mange to create a 3-steps solution :

1. Define a bean in spring context that provide access to a data source
2. Build an implementation of the bean that provide the desired connection.
3. Build a static wrapper that can be accessed by the log4j JDBC appender.

1st step - bean declaration :

    <bean id="springConnection" class="com.dal.entities.SpringConnection" scope="singleton">
    <property name="dataSource" ref="myDataSource" />

the 2nd step - bean implementation - is also simple :

class SpringConnection {

private DataSource dataSource;

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

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

}

the 3rd part - wrapper with static method - is a bit more complex:

public class SpringAccessFactory  {

private final SpringConnection springCon;
private static ApplicationContext context;

private interface Singleton {
    final SpringAccessFactory INSTANCE = new SpringAccessFactory();
}

private SpringAccessFactory()  {

    this.springCon = context.getBean(SpringConnection.class);
}

public static Connection getConnection() throws Exception {
    return Singleton.INSTANCE.springCon.getConnection();
}

public static void setContext( ApplicationContext context) {
    SpringAccessFactory.context = context;
}

}

There are - however - 2 issues I found so far:

• You need to initialize the spring context and send it into the wrapper (SpringAccessFactory.setConetxt) before you start using the logger
• initializing spring context early in program may trigger @PostConstruct methods (if any exists), before you plan to do so.....