Java/Ant/Environment

Environment: ant home, OS and Processor

<?xml version="1.0"?>
<project name="Apache Ant Properties Project" default="properties.environment" basedir=".">

  <target name="properties.environment">
    <property environment="env"/>
    <echo message="Built on: ${env.OS} ${env.PROCESSOR_ARCHITECTURE}"/>
    <echo message="ANT_HOME: ${env.ant_home}"/>
  </target>

</project>

Get environment variables

<?xml version="1.0"?>
<project name="Template Buildfile" default="compile" basedir=".">
  <property name="dir.src" value="src"/>
  <property name="dir.build" value="build"/>
  <property environment="env"/>
  
  <target name="checkProperties">
    <fail unless="env.TOMCAT_HOME">TOMCAT_HOME must be set</fail>
    <fail unless="env.JUNIT_HOME">JUNIT_HOME must be set</fail>
    <fail unless="env.JBOSS_HOME">JBOSS_HOME must be set</fail>
  </target>
  <!-- Creates the output directories -->
  <target name="prepare" depends="checkProperties">
    <mkdir dir="${dir.build}"/>
  </target>
  <target name="clean"
          description="Remove all generated files.">
    <delete dir="${dir.build}"/>
  </target>
  <target name="compile" depends="prepare"
          description="Compile all source code.">
    <echo>Compile code...</echo>
  </target>
</project>

Set system properties in Ant build script

public class ShowProps {
    public static void main(String[] args) {
        System.out.println("Now in ShowProps class...");
        System.out.println("prop1     = " + System.getProperty("prop1"));
        System.out.println("prop2     = " + System.getProperty("prop2"));
        System.out.println("prop3     = " + System.getProperty("prop3"));
        System.out.println("user.home = " + System.getProperty("user.home"));
    }
}

-----------------------------------------
File: build.xml
<?xml version="1.0"?>
<project name="sysprops" default="run" basedir=".">
  <property name="prop1" value="Property 1 from Buildfile"/>
  <property name="prop2" value="Property 2 from Buildfile"/>
  <target name="clean">
    <delete dir="com"/>
  </target>
  <target name="compile">
    <javac srcdir="." destdir=".">
      <classpath path="."/>
    </javac>
  </target>
  <target name="run" depends="compile">
    <echo message="Now in buildfile..."/>
    <echo message="prop1     = ${prop1}"/>
    <echo message="prop2     = ${prop2}"/>
    <echo message="user.home = ${user.home}"/>
    <!-- execute the main() method in a Java class -->
    <java classname="ShowProps">
      <classpath path="."/>
      <!-- pass one of the properties -->
      <sysproperty key="prop1" value="${prop1}"/>
    </java>
  </target>
</project>