linux下启动tomcat 报错
转自 http://blog.csdn.net/xiang520jl/article/details/8958642
linux 下 启动tomcat 报：

Neither the JAVA_HOME nor the JRE_HOME environment variable is defined
At least one of these environment variable is needed to run this program

先看Tomcat的startup.bat，它调用了catalina.bat,而catalina.bat则调用了setclasspath.bat。只要在setclasspath.bat的开头声明环境变量，打开tomcat的bin目录下面的setclasspath.sh，添加红色部分，路径自己修改。windows  下用set。


#!/bin/sh
# -----------------------------------------------------------------------------
# Set CLASSPATH and Java options
#
# $Id: setclasspath.sh 467182 2006-10-23 23:47:06Z markt $
# -----------------------------------------------------------------------------

export JAVA_HOME=/usr/lib/jvm/java-7-sun
export JRE_HOME=/usr/lib/jvm/java-7-sun/jre

# First clear out the user classpath
CLASSPATH=

# Make sure prerequisite environment variables are set
if [ -z "$JAVA_HOME" -a -z "$JRE_HOME" ]; then
# Bugzilla 37284
if $darwin && [ -d "/System/Library/Frameworks/JavaVM.framework/Versions/1.5/Home" ]; then
export JAVA_HOME="/System/Library/Frameworks/JavaVM.framework/Versions/1.5/Home"
else
echo "Neither the JAVA_HOME nor the JRE_HOME environment variable is defined"
echo "At least one of these environment variable is needed to run this program"
exit 1
fi
fi
if [ -z "$JAVA_HOME" -a "$1" = "debug" ]; then
echo "JAVA_HOME should point to a JDK in order to run in debug mode."
exit 1
fi
if [ -z "$JRE_HOME" ]; then
JRE_HOME="$JAVA_HOME"
fi

# If we're running under jdb, we need a full jdk.
if [ "$1" = "debug" -o "$1" = "javac" ] ; then
if [ "$os400" = "true" ]; then
if [ ! -x "$JAVA_HOME"/bin/java -o ! -x "$JAVA_HOME"/bin/javac ]; then
echo "The JAVA_HOME environment variable is not defined correctly"
echo "This environment variable is needed to run this program"
echo "NB: JAVA_HOME should point to a JDK not a JRE"
exit 1
fi
else
if [ ! -x "$JAVA_HOME"/bin/java -o ! -x "$JAVA_HOME"/bin/jdb -o ! -x "$JAVA_HOME"/bin/javac ]; then
echo "The JAVA_HOME environment variable is not defined correctly"
echo "This environment variable is needed to run this program"
echo "NB: JAVA_HOME should point to a JDK not a JRE"
exit 1
fi
fi
fi