CentOS安装JDK

java-version显示当前jdk
rpm -qa | grep java将本机全部的jdk查找出来

rpm -e --nodeps java-1.x.x-openjdk-xxx将此jdk卸载
yum -y remove java java-1.x.x-openjdk-xxx双管齐下，确保卸载

sudo tar -zxf ~/下载/jdk-x.x.x.tar.gz -C /usr/local/java 【使用浏览器默认下载路径】

JAVA_HOME=你的路径
export JRE_HOME=你的路径/jre
export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH
export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
然后
source /etc/profile

在bashrc末尾加上JAVA_HOME=你的路径
然后source ~/.bashrc

  1. cd /usr/local/hadoop
  2. mkdir ./input
  3. cp ./etc/hadoop/*.xml ./input   将配置文件作为输入文件
  4. ./bin/hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-*.jar grep ./input ./output 'dfs[a-z.]+'
  5. cat ./output/*      
运行hadoop的wordcount实例，正常则OK