ANT Build Files

Sample Build File :

<?xml version="1.0"?>
<project name="Hello World" default="info">
   <target name="info">
      <echo>Hello World - Welcome to Apache Ant!</echo>
   </target>
</project>

Output :

Open command prompt and navigate to the folder where we have put build.xml and type 

ant [target name]

We have specified default target name that’s why we can simply use ant command for building project. See below steps -

C:\>ant
Buildfile: C:\build.xml
info:
[echo] Hello World - Welcome to Apache Ant!
BUILD SUCCESSFUL
Total time: 0 seconds

The echo task in the above example is a trivial task that prints a message. In our example, it prints the Hello World message.

Structure of Build File :

  1. Build file require the project element and at least one target element.
  2. Build file should not contain any whitespace before the XML declaration.
  3. Build file generally present in the project’s base directory but it can be present anywhere in the system

The XML element project has three attributes :

Attributes Description Usage
name The Name of the project Optional
default The default target of the build script. A project may have any number of targets. default attribute specifies which target should be considered as the default Mandatory
basedir Specifies the base directory for the project Optional

The XML element target has following attributes :

Attributes Description Usage
name Specifies the name of target Required
depends Specifies the list of targets separated by comma on which the current target depends on Optional
description Specifies the short description of the target Optional
if Specifies that the target would be executed based on condition Optional
unless It adds the target to the dependency list of the specified Extension Point. An Extension Point is similar to a target but it does not have any tasks Optional

Examples :

Consider the following build.xml -

<project>
   <target name="clean" >
  ....
   </target>
   <target name="compile" >
  ....
   </target>
   <target name="package" depends="clean,compile">
  ....
   </target>
   <target name="deploy" depends="package">
  ....
   </target>
</project>

Explanation :

  1. In the above example we have multiple targets in a build file that we wish to execute in particular sequence.
  2. Dependencies are denoted using the depends attribute
  3. In the example, depends attribute states that deploy target may have dependency on package target.
  4. Similarly package target have dependency on the compile and clean targets.