@@ -28,7 +28,6 @@ to let you see, how to do the easiest steps in Ant.</p>
</ul></p>
<a name="prepare"></a>
<h2>Preparing the project</h2>
<p>We want to separate the source from the generated files, so our java source files will
@@ -42,8 +41,8 @@ directory. (Because I am working on Windows, here is the win-syntax - translate
md src
</pre>
<p>This is not a Java tutorial, so just write this code into <tt>src/oata/HelloWorld.java</tt> -
you should guess it's meaning ;-) </p>
<p>The following simple Java class just prints a fixed message out to STDOUT,
so just write this code into <tt>src\oata\HelloWorld.java</tt>. </p>
<pre class="code">
package oata;
@@ -55,18 +54,40 @@ public class HelloWorld {
}
</pre>
<p>Now just try to compile and run that:
<pre class="code">
md build\classes
javac -sourcepath src -d build\classes src\oata\HelloWorld.java
java -cp build\classes oata.HelloWorld
</pre>
which will result in
<pre class="output">
Hello World
</pre>
</p>
<p>Creating a jar-file is not very difficult. But creating a <i>startable</i> jar-file needs more steps: create a
manifest-file containing the start class, creating the target directory and archiving the files.</p>
<pre class="code">
echo Main-Class: oata.HelloWorld>mf
md build\jar
jar cfm build\jar\HelloWorld.jar mf -C build\classes .
java -jar build\jar\HelloWorld.jar
</pre>
<a name="four-steps"></a>
<h2>Four steps to a running application</h2>
<p>Oki-doki - now we have to think about our build process. We <i>have</i> to compile our code, otherwise we couldn't
<p>After finishing the java-only step we have to think about our build process. We <i>have</i> to compile our code, otherwise we couldn't
start the program. Oh - "start" - yes, we could provide a target for that. We <i>should</i> package our application.
Now it's only one class - but if you want to provide a download, no one would download several hundreds files ...
(think about a complex Swing GUI :) - so let us create a jar file. A startable jar file would be nice ... And it's a
(think about a complex Swing GUI - so let us create a jar file. A startable jar file would be nice ... And it's a
good practise to have a "clean" target, which deletes all the generated stuff. Many failures could be solved just
by a "clean build" :-)</p>
by a "clean build". </p>
<p>The buildfile describing that would be:</p>
<p>By default Ant uses <tt>build.xml</tt> as the name for a buildfile, so our <tt>build.xml</tt> would be:</p>
<pre class="code">
<project>
@@ -106,12 +127,59 @@ ant run
ant compile jar run
</pre>
<p>While having a look at the buildfile, we will see some similar steps between Ant and the java-only commands:
<table>
<tr>
<th>java-only</th>
<th>Ant</th>
</tr>
<tr>
<td valign="top"><pre class="code">
md build\classes
javac
-sourcepath src
-d build\classes
src\oata\HelloWorld.java
echo Main-Class: oata.HelloWorld>mf
md build\jar
jar cfm
build\jar\HelloWorld.jar
mf
-C build\classes
.
java -jar build\jar\HelloWorld.jar
</pre></td>
<td valign="top"><pre class="code">
<mkdir dir="build/classes"/>
<javac
srcdir="src"
destdir="build/classes"/>
<i><!-- automatically detected --></i>
<i><!-- obsolete; runtime via manifest tag --></i>
<mkdir dir="build/jar"/>
<jar
destfile="build/jar/HelloWorld.jar"
basedir="build/classes">
<manifest>
<attribute name="Main-Class" value="oata.HelloWorld"/>
</manifest>
</jar>
<java jar="build/jar/HelloWorld.jar" fork="true"/>
</pre></td>
</tr></table>
</p>
<a name="enhance"></a>
<h2>Enhance the build file</h2>
</p>Ok, the build works - but it is not as nice as it should: many time you are referencing the same directories,
main-class and jar-name are hard coded, and while invocation you have to remember the right order of build steps.</p>
<p>Now we have a working buildfile we could do some enhancements: many time you are referencing the
same directories, main-class and jar-name are hard coded, and while invocation you have to remember
the right order of build steps.</p>
<p>The first and second point would be addressed with <i>properties</i>, the third with a special property - an attribute
of the <project>-tag and the fourth problem can be solved using dependencies.</p>
@@ -157,7 +225,7 @@ of the <project>-tag and the fourth problem can be solved using dependenci
</project>
</pre>
<p>Now it's easier, just do a <tt>ant</tt> and you will get</p>
<p>Now it's easier, just do a <tt class="code" >ant</tt> and you will get</p>
<pre class="output">
Buildfile: build.xml
@@ -183,11 +251,11 @@ BUILD SUCCESSFUL
<a name="ext-libs"></a>
<h2>Using external libraries</h2>
<p>Somehow told us not to use syso-statements. For log-Statements we should use a Logging-API - customizable on a high
degree (including switching off during usual life (= not development) execution). We use Log4J, because <ul>
degree (including switching off during usual life (= not development) execution). We use Log4J for that , because <ul>
<li>it is not part of the JDK (1.4+) and we want to show how to use external libs</li>
<li>it can run under JDK 1.2 (as Ant)</li>
<li>it's highly configurable</li>
<li>it's from Apache : -)</li>
<li>it's from Apache ; -)</li>
</ul></p>
<p>We store our external libraries in a new directory <tt>lib</tt>. Log4J can be
<a href="http://www.apache.org/dist/logging/log4j/1.2.9/logging-log4j-1.2.9.zip">downloaded [1]</a> from Logging's Homepage.
Jan Materne