如何配置hadoop环境变量

典型的配置：

export HADOOP_HOME=/usr/local/hadoop
export HADOOP_MAPRED_HOME=$HADOOP_HOME
export HADOOP_COMMON_HOME=$HADOOP_HOME
export HADOOP_HDFS_HOME=$HADOOP_HOME
export HADOOP_CONF_DIR=$HADOOP_HOME/etc/hadoop
export YARN_HOME=$HADOOP_HOME
export YARN_CONF_DIR=$HADOOP_HOME/etc/hadoop
export PATH=$PATH:$JAVA_HOME/bin:$HADOOP_HOME/bin:$HADOOP_HOME/sbin
export LD_LIBRARY_PATH=$JAVA_HOME/jre/lib/amd64/server:/usr/local/lib:$HADOOP_HOME/lib/native
export JAVA_LIBRARY_PATH=$LD_LIBRARY_PATH:$JAVA_LIBRARY_PATH