使用属性文件和Maven配置文件外部化Web App Config的最佳方法

Question

Have a Java Maven web app which has hardcoded properties set in the following configuration files residing in:

src/main/resources/database.xml

<beans xmlns="http://www.springframework.org/schema/beans">
      <bean id="aDatasource"  class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
      <property name="driverClassName"><value>com.mysql.jdbc.Driver</value></property>
      <property name="url"><value>jdbc:mysql://anIpAddress/mydatabase?zeroDateTimeBehavior=convertToNull</value></property>
      <property name="username"><value>root</value></property>
      <property name="password"><value>password</value></property>
   </bean> 
</beans>

src/main/resources/log4.j.properties

log4j.appender.RF.File=/opt/apache-tomcat-7.0.78/webapps/myapp/WEB-INF/classes/logs.log

Before I run maven clean install, I am constantly editing these files by replacing inside database.xml:

aniPAddress with localhost
root with my local database's root user
password with my local database's root password

Inside log4.properties:

/opt/apache-tomcat-7.0.78/ with $CATALINA_HOME

Question(s):

1. Is there a way to externalize the configuration files so I don't have to explicitly change it everytime I do a fresh Git checkout?

eg

should I create an application.properties file located inside src/main/resources containing the following properties:

database.url = localhost
database.user = root
database.password = 
tomcat.home = $CATALINA_HOME or /etc/tomcat7/

How would these be explicitly set inside database.xml and / or log4j.properties?

2. Is there a way to use maven profile features to switch config properties?

eg

maven clean -install -p dev 
maven clean -install -p prod

How to configure the pom.xml file to reflect the behavior required in question 1?

Answer 1

You can use the resource filtering, see https://maven.apache.org/plugins/maven-resources-plugin/examples/filter.html

Given the following pom:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>test</groupId>
    <artifactId>test</artifactId>
    <version>1.0-SNAPSHOT</version>

    <build>
        <resources>
            <resource>
                <directory>${project.basedir}/src/main/filtered-resources</directory>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>
<profiles>
    <profile>
        <id>dev</id>
        <properties>
            <jdbc.url>localhost</jdbc.url>
        </properties>
    </profile>
    <profile>
        <id>prod</id>
        <properties>
            <jdbc.url>server.prod</jdbc.url>
        </properties>
    </profile>
</profiles>
</project>

And the following content in the file src/main/filtered-resource/application.properties:

database.url = ${jdbc.url}

with "mvn -Pdev process-resource" the file target/classes/application.properties will contain:

database.url = localhost

and with "mvn -Pprod process-resource":

database.url = server.prod

Answer 2

Found the answer to my first question regarding how to load the Spring datasource database.xml upon server startup based on external properties:

It's as simple as putting this entry inside the database.xml file:

<bean id="propertyPlaceholder" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> 
    <property name="ignoreResourceNotFound" value="true" />
    <property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
    <property name="location" value="file:/proplocation/database.properties"></property>
</bean>

No one knows the answer to Queston # 2?

Is there a way to use maven profile features to switch config properties?

eg

maven clean -install -p dev
maven clean -install -p prod