Ant For Beginners

• Download Apache Ant Binary Distributions from here
• Set path to %ANT_HOME%/bin (Type ant -version to test whether path is set or not).
• Now we need a build.xml to create folder hierarchy.
• Here is a basic build.xml which will create src, resources, build folders. These are not standard folders. One can create their own folders and define the folder hierarchy by modifying build.xml. In the following build.xml, I have created src folder to put source code(Some times properties files also), resources folder to keep all the resources(images, data files etc) and build folder to keep class files and JAR file.
• Just copy following code in a file and save it as build.xml. Go to the path and type

      ant run

• If you have a source code already then copy your source code in src folder, resources in resources folder and re- run ant.

<?xml version="1.0" encoding="UTF-8"?>
<project name="InfraTransform" default="build-jar" basedir=".">
    <property name="src.dir" value="src" />
    <property name="build.dir" value="build" />
    <property name="resources.dir" value="resources" />
    <property name="classes.dir" value="${build.dir}/classes" />
    <property name="jar.dir" value="${build.dir}/jar" />
    <property name="lib.dir" value="lib" />
    <property name="main-class" value="com.test.MainClass" />

    <path id="classpath">
        <fileset dir="${lib.dir}" includes="*.jar" />
    </path>

    <pathconvert property="manifest.classpath" pathsep=" ">
        <path refid="classpath" />
        <mapper>
            <chainedmapper>
                <flattenmapper />
                <globmapper from="*.jar" to="${lib.dir}/*.jar" />
            </chainedmapper>
        </mapper>
    </pathconvert>

    <target name="clean">
        <delete dir="${build.dir}" />
    </target>

    <target name="compile" depends="clean">
        <mkdir dir="${classes.dir}" />
        <javac srcdir="${src.dir}" destdir="${classes.dir}" classpathref="classpath" />
    </target>

    <target name="build-jar" depends="compile">
        <mkdir dir="${jar.dir}" />
        <jar destfile="${jar.dir}/${ant.project.name}.jar" basedir="${classes.dir}">
            <fileset dir="${resources.dir}" includes="**/*.*" />
            <fileset dir="${src.dir}" excludes="**/*.java" />
            <manifest>
                <attribute name="Built-By" value="${user.name}" />
                <attribute name="Main-Class" value="${main-class}" />
                <attribute name="Class-Path" value="${manifest.classpath}" />
            </manifest>
        </jar>
    </target>

    <target name="run">
        <java fork="true" classname="${main-class}">
            <classpath>
                <path refid="classpath" />
                <path location="${jar.dir}/${ant.project.name}.jar" />
            </classpath>
        </java>
    </target>


</project>

Let's try to understand the build.xml a bit.

• In general build.xml starts with project tag, and property tags are used to define some constants, so that we can refer those names in the rest of the code.( In our example, we used properties to define folder paths).
• If you have more properties, then keep all the properties in a file and name the files as build.properties. Refer this file as property in build.xml.

          <property file="build.properties"/>

• Let's see a sample build.properties

         src.dir = src
         build.dir = build
        resources.dir = resources
        classes.dir = ${build.dir}/classes
        jar.dir = ${build.dir}/jar
       lib.jar = lib
       main-class = com.test.MainClass

• target in build.xml is like function in traditional programming. Write your logic(Creating directories/files, deleting them, running instructions etc) in a block and name that block as target name = "somename". You can call function from command prompt.

      ant <targetname>

• depends name it self tells us that before this function runs, there is a dependent function which needs to be run.

I think, this is enough to start ant, if you understand a bit, then go through official material and other sources.

Further Reading:
Tutorial: Hello World with Apache Ant
Apache Ant - Tutorial