1.源码位置 SVN获取

2.进入目录  ant 即可实现编译（保证ant安装正确，build.xml有此文件）

   1.根据build.xml 会自动生成相应的class与jar

3.手工生成相应的包

hadoop-0.20.2-ant.jar

hadoop-0.20.2-core.jar

hadoop-0.20.2-examples.jar

hadoop-0.20.2-test.jar

hadoop-0.20.2-tools.jar

 

比如手工生成 hadoop-0.20.2-core.jar

需重写build.xml 如下

<?xml version="1.0"?>

<project name="Hadoop" default="jar"

   xmlns:ivy="antlib:org.apache.ivy.ant">

  <property file="${user.home}/build.properties" />

  <property file="${basedir}/build.properties" />

  <property name="Name" value="Hadoop"/>

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

  <property name="version" value="0.20.3-dev"/>

  <property name="final.name" value="${name}-${version}"/>

  <property name="lib.dir" value="${basedir}/lib"/>

  <property name="conf.dir" value="${basedir}/conf"/>

  <property name="build.dir" value="${basedir}/build"/>

  <property name="build.classes" value="${build.dir}/classes"/>

  <property name="build.webapps" value="${build.dir}/webapps"/>

 

  <target name="jar" description="Make hadoop.jar">

    <tar compression="gzip" destfile="${build.classes}/bin.tgz">

      <tarfileset dir="bin" mode="755"/>

    </tar>

    <jar jarfile="${build.dir}/${final.name}-core.jar"

         basedir="${build.classes}">

      <manifest>

        <section name="org/apache/hadoop">

          <attribute name="Implementation-Title" value="Hadoop"/>

          <attribute name="Implementation-Version" value="${version}"/>

          <attribute name="Implementation-Vendor" value="Apache"/>

        </section>

      </manifest>

      <fileset file="${conf.dir}/commons-logging.properties"/>

      <fileset file="${conf.dir}/log4j.properties"/>

      <fileset file="${conf.dir}/hadoop-metrics.properties"/>

      <zipfileset dir="${build.webapps}" prefix="webapps"/>

    </jar>

  </target>

</project>

4.将编译之后的

hadoop-0.20.2-ant.jar

hadoop-0.20.2-core.jar(经过测试，可以启动hadoop，说明没问题)

hadoop-0.20.2-examples.jar

hadoop-0.20.2-test.jar

hadoop-0.20.2-tools.jar

替换至hadoop目录

5.下一步，将试着修改源代码