解决mvn command not found

环境变量是这样写：

export JAVA_HOME=/usr/java/jdk1.8.0_111
export CLASSPATH=$CLASSPATH:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export M3_HOME=/usr/local/maven3
export PATH=$JAVA_HOME/bin:$M3_HOME/bin:$PATH