安装maven
hadoop源码是使用maven组织管理的，必须下载maven。从maven官网下载，下载地址是http://maven.apache.org/download.cgi，选择 apache-maven-3.1.0-bin.tar.gz 下载，不要选择3.1下载。
执行以下命令解压缩jdk
tar -zxvf apache-maven-3.1.0-bin.tar.gz
会生成一个文件夹apache-maven-3.1.0，然后设置环境变量中。
执行命令vi /etc/profile，编辑结果如下所示
MAVEN_HOME=/usr/maven/apache-maven-3.1.0
export MAVEN_HOME
export PATH=${PATH}:${MAVEN_HOME}/bin
保存退出文件后，执行以下命令
source /etc/profile
mvn -version
如果看到下面的显示信息，证明配置正确了。
安装findbugs（可选步骤）
findbugs是用于生成文档的。如果不需要编译生成文档，可以不执行该步骤。从findbugs官网下载findbugs，下载地址是http://sourceforge.jp/projects/sfnet_findbugs/releases/，选择findbugs-3.0.0-dev-20131204-e3cbbd5.tar.gz下载。
执行以下命令解压缩jdk
tar -zxvf findbugs-3.0.0-dev-20131204-e3cbbd5.tar.gz
会生成一个文件夹findbugs-3.0.0-dev-20131204-e3cbbd5，然后设置环境变量中。
执行命令vi /etc/profile，编辑结果如下所示
FINDBUGS_HOME=/usr/local/findbugs
export FINDBUGS_HOME
export PATH=${PATH}:${FINDBUGS_HOME}/bin
保存退出文件后，执行以下命令
source /etc/profile
findbugs -version
如果看到下面的显示信息，证明配置正确了。
安装protoc
hadoop使用protocol buffer通信，从protoc官网下载protoc，下载地址是https://code.google.com/p/protobuf/downloads/list，选择protobuf-2.5.0.tar.gz 下载。
为了编译安装protoc，需要下载几个工具，顺序执行以下命令
yum install gcc
yum intall gcc-c++
yum install make
如果操作系统是redhat6那么gcc和make已经安装了。在命令运行时，需要用户经常输入“y”。
然后执行以下命令解压缩protobuf
tar -zxvf protobuf-2.5.0.tar.gz
会生成一个文件夹protobuf-2.5.0，执行以下命令编译protobuf。
cd protobuf-2.5.0
./configure --prefix=/usr/local/protoc/
make && make install
只要不出错就可以了。
执行完毕后，编译后的文件位于/usr/local/protoc/目录下，我们设置一下环境变量
执行命令vi /etc/profile，编辑结果如下所示
export PATH=${PATH}:/usr/local/protoc/bin
保存退出文件后，执行以下命令
source /etc/profile
protoc --version
如果看到下面的显示信息，证明配置正确了。
安装其他依赖
顺序执行以下命令
yum install cmake
yum install openssl-devel
yum install ncurses-devel
安装完毕即可。
编译hadoop2.4源码
从hadoop官网下载2.4稳定版，下载地址是http://apache.fayea.com/apache-mirror/hadoop/common/hadoop-2.4.0/，下载hadoop-2.4.0-src.tar.gz 下载。
执行以下命令解压缩jdk
tar -zxvf hadoop-2.4.0-src.tar.gz 如图所示：
进入到目录/usr/local/hadoop-2.2.0-src中，执行命令
mvn package -DskipTests-Pdist,native,docs
如果没有安装findbugs，把上面命令中的docs去掉即可，就不必生成文档了。
该命令会从外网下载依赖的jar，编译hadoop源码，需要花费很长时间。
在等待n久之后，可以看到如下的结果：
main:
[INFO] Executedtasks
[INFO]
[INFO] ---maven-javadoc-plugin:2.8.1:jar (module-javadocs) @ hadoop-dist ---
[INFO] Buildingjar: /usr/local/comile_hadoop/hadoop-2.4.0-src/hadoop-dist/target/hadoop-dist-2.4.0-javadoc.jar
[INFO]------------------------------------------------------------------------
[INFO] ReactorSummary:
[INFO]
[INFO] ApacheHadoop Main ................................ SUCCESS [30.591s]
[INFO] ApacheHadoop Project POM ......................... SUCCESS [8.024s]
[INFO] ApacheHadoop Annotations ......................... SUCCESS [19.005s]
[INFO] ApacheHadoop Assemblies .......................... SUCCESS [0.908s]
[INFO] ApacheHadoop Project Dist POM .................... SUCCESS [16.797s]
[INFO] ApacheHadoop Maven Plugins ....................... SUCCESS [14.676s]
[INFO] ApacheHadoop MiniKDC ............................. SUCCESS [20.931s]
[INFO] ApacheHadoop Auth ................................ SUCCESS [52.092s]
[INFO] ApacheHadoop Auth Examples ....................... SUCCESS [10.980s]
[INFO] ApacheHadoop Common .............................. SUCCESS [11:32.369s]
[INFO] ApacheHadoop NFS ................................. SUCCESS [24.092s]
[INFO] ApacheHadoop Common Project ...................... SUCCESS [0.066s]
[INFO] ApacheHadoop HDFS ................................ SUCCESS [23:42.723s]
[INFO] ApacheHadoop HttpFS .............................. SUCCESS [59.023s]
[INFO] ApacheHadoop HDFS BookKeeper Journal ............. SUCCESS [13.856s]
[INFO] ApacheHadoop HDFS-NFS ............................ SUCCESS [18.362s]
[INFO] ApacheHadoop HDFS Project ........................ SUCCESS [0.095s]
[INFO]hadoop-yarn ....................................... SUCCESS [0.153s]
[INFO]hadoop-yarn-api ................................... SUCCESS [2:19.762s]
[INFO]hadoop-yarn-common ................................ SUCCESS [1:09.344s]
[INFO]hadoop-yarn-server ................................ SUCCESS [0.214s]
[INFO]hadoop-yarn-server-common ......................... SUCCESS [16.529s]
[INFO]hadoop-yarn-server-nodemanager .................... SUCCESS [39.870s]
[INFO]hadoop-yarn-server-web-proxy ...................... SUCCESS [7.958s]
[INFO]hadoop-yarn-server-applicationhistoryservice ...... SUCCESS [10.571s]
[INFO]hadoop-yarn-server-resourcemanager ................ SUCCESS [30.395s]
[INFO]hadoop-yarn-server-tests .......................... SUCCESS [3.403s]
[INFO]hadoop-yarn-client ................................ SUCCESS [10.963s]
[INFO]hadoop-yarn-applications .......................... SUCCESS [0.073s]
[INFO]hadoop-yarn-applications-distributedshell ......... SUCCESS [5.617s]
[INFO]hadoop-yarn-applications-unmanaged-am-launcher .... SUCCESS [8.685s]
[INFO]hadoop-yarn-site .................................. SUCCESS [0.415s]
[INFO]hadoop-yarn-project ............................... SUCCESS [10.655s]
[INFO]hadoop-mapreduce-client ........................... SUCCESS [0.498s]
[INFO]hadoop-mapreduce-client-core ...................... SUCCESS [1:09.961s]
[INFO]hadoop-mapreduce-client-common .................... SUCCESS [35.913s]
[INFO]hadoop-mapreduce-client-shuffle ................... SUCCESS [9.373s]
[INFO]hadoop-mapreduce-client-app ....................... SUCCESS [24.999s]
[INFO]hadoop-mapreduce-client-hs ........................ SUCCESS [20.270s]
[INFO]hadoop-mapreduce-client-jobclient ................. SUCCESS [22.128s]
[INFO]hadoop-mapreduce-client-hs-plugins ................ SUCCESS [2.831s]
[INFO] ApacheHadoop MapReduce Examples .................. SUCCESS [16.102s]
[INFO]hadoop-mapreduce .................................. SUCCESS [8.448s]
[INFO] ApacheHadoop MapReduce Streaming ................. SUCCESS [14.307s]
[INFO] ApacheHadoop Distributed Copy .................... SUCCESS [20.261s]
[INFO] ApacheHadoop Archives ............................ SUCCESS [5.800s]
[INFO] ApacheHadoop Rumen ............................... SUCCESS [22.152s]
[INFO] ApacheHadoop Gridmix ............................. SUCCESS [11.213s]
[INFO] ApacheHadoop Data Join ........................... SUCCESS [5.208s]
[INFO] ApacheHadoop Extras .............................. SUCCESS [6.728s]
[INFO] ApacheHadoop Pipes ............................... SUCCESS [6.053s]
[INFO] ApacheHadoop OpenStack support ................... SUCCESS [25.927s]
[INFO] ApacheHadoop Client .............................. SUCCESS [8.744s]
[INFO] ApacheHadoop Mini-Cluster ........................ SUCCESS [0.154s]
[INFO] ApacheHadoop Scheduler Load Simulator ............ SUCCESS [15.622s]
[INFO] ApacheHadoop Tools Dist .......................... SUCCESS [9.695s]
[INFO] ApacheHadoop Tools ............................... SUCCESS [0.110s]
[INFO] ApacheHadoop Distribution ........................ SUCCESS [3:59.323s]
[INFO]------------------------------------------------------------------------
[INFO] BUILDSUCCESS
[INFO]------------------------------------------------------------------------
[INFO] Totaltime: 56:17.413s
[INFO] Finishedat: Thu May 22 17:13:49 CST 2014
[INFO] FinalMemory: 88M/371M
[INFO]------------------------------------------------------------------------
[root@icity2hadoop-2.4.0-src]#
好了，编译完成了。
编译后的代码在hadoop-2.4.0-src/hadoop-dist/target下面，如下图所示：
