How to generate build.xml for a new java project?

I am learning about build.xml file for ant build. I have a simple "Hello World" project in Eclipse.

Is there any 开发者_Python百科way to generate a build.xml file in Eclipse for this project?

Thanks in Advance.

Yes - click on File -> Export -> General -> Ant Buildfiles and specify the file name, project, etc.

I find that I've got a single generic Ant build.xml that I reuse again and again. It's not something that has to be done from scratch every time.

If you're learning Ant, what's the point of using a generated build.xml?

Something like this:

<?xml version="1.0" encoding="UTF-8"?>
<project name="xslt-converter" basedir="." default="package">

    <property name="version" value="1.6"/>
    <property name="haltonfailure" value="no"/>

    <property name="out" value="out"/>

    <property name="production.src" value="src"/>
    <property name="production.lib" value="lib"/>
    <property name="production.resources" value="config"/>
    <property name="production.classes" value="${out}/production/${ant.project.name}"/>

    <property name="test.src" value="test"/>
    <property name="test.lib" value="lib"/>
    <property name="test.resources" value="config"/>
    <property name="test.classes" value="${out}/test/${ant.project.name}"/>

    <property name="exploded" value="out/exploded/${ant.project.name}"/>
    <property name="exploded.classes" value="${exploded}/WEB-INF/classes"/>
    <property name="exploded.lib" value="${exploded}/WEB-INF/lib"/>

    <property name="reports.out" value="${out}/reports"/>
    <property name="junit.out" value="${reports.out}/junit"/>
    <property name="testng.out" value="${reports.out}/testng"/>

    <path id="production.class.path">
        <pathelement location="${production.classes}"/>
        <pathelement location="${production.resources}"/>
        <fileset dir="${production.lib}">
            <include name="**/*.jar"/>
            <exclude name="**/junit*.jar"/>
            <exclude name="**/*test*.jar"/>
        </fileset>
    </path>

    <path id="test.class.path">                            
        <path refid="production.class.path"/>
        <pathelement location="${test.classes}"/>
        <pathelement location="${test.resources}"/>
        <fileset dir="${test.lib}">
            <include name="**/junit*.jar"/>
            <include name="**/*test*.jar"/>
        </fileset>
    </path>

    <path id="testng.class.path">
        <fileset dir="${test.lib}">
            <include name="**/testng*.jar"/>
        </fileset>
    </path>

    <available file="${out}" property="outputExists"/>

    <target name="clean" description="remove all generated artifacts" if="outputExists">
        <delete dir="${out}" includeEmptyDirs="true"/>
        <delete dir="${reports.out}" includeEmptyDirs="true"/>
    </target>

    <target name="create" description="create the output directories" unless="outputExists">
        <mkdir dir="${production.classes}"/>
        <mkdir dir="${test.classes}"/>
        <mkdir dir="${reports.out}"/>
        <mkdir dir="${junit.out}"/>
        <mkdir dir="${testng.out}"/>
        <mkdir dir="${exploded.classes}"/>
        <mkdir dir="${exploded.lib}"/>
    </target>

    <target name="compile" description="compile all .java source files" depends="create">
        <!-- Debug output
                <property name="production.class.path" refid="production.class.path"/>
                <echo message="${production.class.path}"/>
        -->
        <javac srcdir="src" destdir="${out}/production/${ant.project.name}" debug="on" source="${version}">
            <classpath refid="production.class.path"/>
            <include name="**/*.java"/>
            <exclude name="**/*Test.java"/>
        </javac>
        <javac srcdir="${test.src}" destdir="${out}/test/${ant.project.name}" debug="on" source="${version}">
            <classpath refid="test.class.path"/>
            <include name="**/*Test.java"/>
        </javac>
    </target>

    <target name="junit-test" description="run all junit tests" depends="compile">
        <!-- Debug output
                <property name="test.class.path" refid="test.class.path"/>
                <echo message="${test.class.path}"/>
        -->
        <junit printsummary="yes" haltonfailure="${haltonfailure}">
            <classpath refid="test.class.path"/>
            <formatter type="xml"/>
            <batchtest fork="yes" todir="${junit.out}">
                <fileset dir="${test.src}">
                    <include name="**/*Test.java"/>
                </fileset>
            </batchtest>
        </junit>
        <junitreport todir="${junit.out}">
            <fileset dir="${junit.out}">
                <include name="TEST-*.xml"/>
            </fileset>
            <report todir="${junit.out}" format="frames"/>
        </junitreport>
    </target>

    <taskdef resource="testngtasks" classpathref="testng.class.path"/>
    <target name="testng-test" description="run all testng tests" depends="compile">
        <!-- Debug output
                <property name="test.class.path" refid="test.class.path"/>
                <echo message="${test.class.path}"/>
        -->
        <testng classpathref="test.class.path" outputDir="${testng.out}" haltOnFailure="${haltonfailure}" verbose="2" parallel="methods" threadcount="50">
            <classfileset dir="${out}/test/${ant.project.name}" includes="**/*.class"/>
        </testng>
    </target>

    <target name="exploded" description="create exploded deployment" depends="testng-test">
        <copy todir="${exploded.classes}">
            <fileset dir="${production.classes}"/>
        </copy>
        <copy todir="${exploded.lib}">
            <fileset dir="${production.lib}"/>
        </copy>
    </target>

    <target name="package" description="create package file" depends="exploded">
        <jar destfile="${out}/${ant.project.name}.jar" basedir="${production.classes}" includes="**/*.class"/>
    </target>

</project>