How to include properties from external file to hibernate.cfg.xml?

Question

I need to be able to store database config properties in src|main|java|dbConnection.properties and include it to hibernate.cfg.xml in form of

Answer 1

Following this, this and this I came up with the following Maven configuration that replaces/filters placeholders from your hibernate.cfg.xml file with properties from a properties file:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-resources-plugin</artifactId>
            <version>2.6</version>
            <executions>

                <execution>
                    <id>copy-resources</id>
                    <!-- here the phase you need -->
                    <phase>validate</phase>
                    <goals>
                        <goal>copy-resources</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>${basedir}/target/extra-resources</outputDirectory>
                        <resources>
                            <resource>
                                <directory>src/main/resources</directory>
                                <filtering>true</filtering>
                            </resource>
                        </resources>
                    </configuration>
                </execution>
            </executions>

        </plugin>
    </plugins>

    <!-- Specify the file that contains the value to replace the placeholders -->
    <filters>
        <filter>src/main/resources/dbConnection.properties</filter>
    </filters>
    <resources>
        <resource>
            <directory>src/main/resources</directory>
            <filtering>true</filtering>
            <excludes>
                <exclude>*</exclude>
            </excludes>
            <includes>
                <include>hibernate.cfg.xml</include>
            </includes>
        </resource>
    </resources>
</build>

With this configuration, you can run the validate Maven goal to generate the filtered files and see if they are relpaced correctly

This is of course useful if you are using Maven.

Answer 2

You state that you use Spring then why not let Spring do all the hard work. Let a property placeholder replace the placeholders you want.

<context:property-placeholder location="classpath:dbConnection.properties" />

<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="hibernateProperties">
       <map>
            <entry key="connection.driver_class" value="${DRIVER}" />
            <entry key="connection.username" value="${USERNAME}" />
            <entry key="connection.password" value="${PASSWORD}" />
            <entry key="transaction.factory_class" value="org.hibernate.transaction.JDBCTransactionFactory" />
        </map>
    <property>
 </bean>

Free advice instead of using the internal hibernate connection stuff (which isn't adviced to be used in production) configure a datasource in spring and wire that to your LocalSessionFactoryBean

Answer 3

You can do it programmatically.

hibernate.cfg.xml should be as following.

<?xml version='1.0' encoding='utf-8'?>
    <!DOCTYPE hibernate-configuration PUBLIC
            "-//Hibernate/Hibernate Configuration DTD//EN"
            "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
    <hibernate-configuration>
        <session-factory>
            <property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>
        </session-factory>
    </hibernate-configuration>

dbConnection.properties

connection.driver_class=org.postgresql.Driver
connection.username=postgres
connection.password=postgres

And when creating the SessionFactory you can do the following.

Properties dbConnectionProperties = new Properties();
try {
    dbConnectionProperties.load(ClassLoader.getSystemClassLoader().getResourceAsStream("dbConnection.properties"));
} catch(Exception e) {
    // Log
}

SessionFactory sessionFactory = new Configuration().mergeProperties(dbConnectionProperties).configure().buildSessionFactory();