看标题就知道，这个是开发一个java应用的利器组合，使用ant完成工程的构建（build），使用junit完成单元测试，使用cobertura完成代码覆盖测试，也可以辅助查找性能瓶颈和一些类型的bug，下面是一个完整的build.xml范例，可以完全拿来用，不需任何修改，只要你的目录和这里的目录一致（应该也是很通用的）：

下载下面的build.xml文件

文件内容：
<project default="all">
    <!?c =================================================================== ?c>
    <!?c                               definitions                           ?c>
    <!?c =================================================================== ?c>   
    <property name="base-dir" location="." />
    <property name="lib-dir" location="${base-dir}/lib" />
    <property name="src-dir" location="${base-dir}/src" />
    <property name="testcase-dir" location="${base-dir}/test" />
    <property name="out-dir" location="${base-dir}/classes" />
    <property name="report-dir" location="${base-dir}/report" />
    <property name="junit-dir" location="${report-dir}/junit" />
    <property name="junit-xml-dir" location="${junit-dir}/xml" />
    <property name="junit-html-dir" location="${junit-dir}/html" />
    <property name="cobertura-dir" location="${report-dir}/cobertura" />
    <property name="cobertura-xml-dir" location="${cobertura-dir}/xml" />
    <property name="cobertura-html-dir" location="${cobertura-dir}/html" />
    <property name="instrumented-dir" location="${report-dir}/instrumented" />
    <property name="instrument-file" location="${instrumented-dir}/cobertura.ser" />
    <property name="cobertura.dir" value="${instrumented-dir}" />
   
   
    <path id="classpath.all">
        <pathelement location="${out-dir}" />
        <fileset id="alljars" dir="${lib-dir}">
            <include name="**/*.jar" />
        </fileset>
    </path>

    <!?c include the cobertura building jars ?c> 
    <path id="cobertura.classpath">
        <path refid="classpath.all" />
    </path>   
   
    <!?c define the cobertura property file ?c> 
    <taskdef classpathref="cobertura.classpath" resource="tasks.properties"/>
   
    <!?c =================================================================== ?c>
    <!?c                            project targets                          ?c>
    <!?c =================================================================== ?c>
   
    <target name="init" description="initialize the project env.">
        <!?c create the output folder ?c> 
        <mkdir dir="${out-dir}" />
        <mkdir dir="${report-dir}" />
        <copy todir="${out-dir}">
            <fileset dir="${src-dir}" includes="**/*.properties" />
        </copy>
    </target>

     <target name="compile" depends="init">
        <javac srcdir="${src-dir}" destdir="${out-dir}">
            <classpath refid="classpath.all" />
        </javac>
    </target>
  
    <!?c =================================================================== ?c>
    <!?c                            unit test targets                        ?c>
    <!?c =================================================================== ?c>
   
    <!?c - - - - - - - - - - - - - - - - -
      target: init
      initialize the build env            
    - - - - - - - - - - - - - - - - - ?c>   
    <target name="init-test" description="initialize the test env.">
        <!?c create the output folder ?c> 
        <mkdir dir="${junit-dir}" />
        <mkdir dir="${junit-xml-dir}" />
        <mkdir dir="${junit-html-dir}" />
    </target>

    <!?c - - - - - - - - - - - - - - - - -
      target: compile-test
      compile the test cases                
    - - - - - - - - - - - - - - - - - ?c>    
    <target name="compile-test" depends="compile">
        <javac srcdir="${testcase-dir}" destdir="${out-dir}">      
            <classpath refid="classpath.all" />
        </javac>
    </target>

    <!?c =================================
      target: test
      run the unit test
     ================================= ?c>   
    <target name="test" depends="init-test">
        <junit fork="yes" printsummary="on" maxmemory="100m">
            <sysproperty key="net.sourceforge.cobertura.datafile"
                file="${instrument-file}" />

            <classpath location="${instrumented-dir}" />
            <classpath refid="cobertura.classpath" />
                  
            <formatter type="xml" />
            <batchtest todir="${junit-xml-dir}">
                <fileset dir="${out-dir}">
                    <include name="**/test*.class" />
                    <exclude name="**/*$*.class" />
                </fileset>
            </batchtest>
        </junit>
        <junitreport todir="${junit-xml-dir}">
            <fileset dir="${junit-xml-dir}">
                <include name="test-*.xml" />
            </fileset>
            <report format="frames" todir="${junit-html-dir}" />
        </junitreport>
    </target>
   
    <!?c =================================================================== ?c>
    <!?c                      code coverage targets                          ?c>
    <!?c =================================================================== ?c>
   

    <!?c - - - - - - - - - - - - - - - - -
      target: init
      initialize the build env. for code coverage                     
    - - - - - - - - - - - - - - - - - ?c>   
    <target name="init-coverage" description="initialize the build env.">
        <!?c create the output folder ?c> 
        <mkdir dir="${instrumented-dir}" />
        <mkdir dir="${cobertura-dir}" />
        <mkdir dir="${cobertura-xml-dir}" />
        <mkdir dir="${cobertura-html-dir}" />
    </target>
   
    <target name="compile-coverage" depends="init">
        <javac srcdir="${src-dir}:${testcase-dir}" destdir="${out-dir}" debug="true" > 
            <classpath refid="cobertura.classpath" />
        </javac>
    </target>

    <!?c =================================
      target: instrument
      instrument into the class files, but
      exclude test classes
     ================================= ?c>    
    <target name="instrument" depends="init-coverage,compile-coverage" description="instrument into the class files">
        <!?c
          instrument the application classes, writing the
          instrumented classes into ${instrumented.dir}.
        ?c>
        <cobertura-instrument todir="${instrumented-dir}" datafile="${instrument-file}">
            <!?c
                the following line causes instrument to ignore any
                source line containing a reference to log4j, for the
                purposes of coverage reporting.
            ?c>
            <ignore regex="org.apache.log4j.*" />
            <fileset dir="${out-dir}">
                <!?c
                  instrument all the application classes, but
                  don’t instrument the test classes.
                ?c>
                <include name="**/*.class" />
                <exclude name="**/test*.class" />
            </fileset>
        </cobertura-instrument>
    </target>       
   
    <!?c =================================
      target: coverage-check
      check the code coverage by given rates.
     ================================= ?c> 
    <target name="coverage-check" description="check the code coverage by given rates">
      <cobertura-check branchrate="34" totallinerate="100" />
    </target>
   
    <!?c =================================
      target: coverage-report-xml
      generate code coverage report by xml format
     ================================= ?c>     
    <target name="coverage-report-xml" description="generate xml report">
      <!?c generate an xml file containing the coverage data using the "srcdir" attribute. ?c>
      <cobertura-report srcdir="${src-dir}" destdir="${cobertura-xml-dir}" format="xml" datafile="${instrument-file}"/>
    </target>
   
    <!?c =================================
      target: coverage-report-html
      generate code coverage report by html format
     ================================= ?c>   
    <target name="coverage-report-html">
    <!?c
        generate a series of html files containing the coverage
        data in a user-readable form using nested source filesets.
    ?c>
      <cobertura-report destdir="${cobertura-html-dir}" datafile="${instrument-file}">
        <fileset dir="${src-dir}">
          <include name="**/*.java"/>
        </fileset>
      </cobertura-report>
    </target>
   
    <!?c run the code coverage individual ?c>
    <target name="coverage" depends="compile-coverage,instrument,test,coverage-report-html"
        description="compile, instrument ourself, run the tests and generate junit and code coverage reports."/>
   
    <!?c =================================================================== ?c>
    <!?c                           public targets                            ?c>
    <!?c =================================================================== ?c>
   
    <target name="clean">
        <delete quiet="true" includeemptydirs="true">
            <fileset dir="${report-dir}">
                <exclude name=".cvsignore" />
                <exclude name="cvs" />
            </fileset>
            <fileset dir="${out-dir}">
            </fileset>
        </delete>
    </target>
   
   
    <!?c =================================================================== ?c>
    <!?c                           global targets                            ?c>
    <!?c =================================================================== ?c>
   
    <target name="all" depends="compile" />
   
    <target name="junit" depends="clean, compile-test, test" />

    <target name="full" depends="clean, coverage" />

</project>