linux下tomcat无法启动

在linux下安装好tomcat启动时报如下错误：

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

原因：找不到jdk或者jre路径。

解决办法：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，路径修改为自己机器jdk和jre路径即可。

#!/bin/sh

# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# -----------------------------------------------------------------------------
# Set CLASSPATH and Java options
#
# $Id: setclasspath.sh 795037 2009-07-17 10:52:16Z markt $
# -----------------------------------------------------------------------------

export JAVA_HOME=/opt/zimbra/jdk1.6.0_31
export JRE_HOME=/opt/zimbra/jdk1.6.0_31/jre

# Make sure prerequisite environment variables are set
if [ -z "$JAVA_HOME" -a -z "$JRE_HOME" ]; then
# Bugzilla 37284 (reviewed).
if $darwin; then
if [ -d "/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home" ]; then
export JAVA_HOME="/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home"
fi
else
JAVA_PATH=`which java 2>/dev/null`
if [ "x$JAVA_PATH" != "x" ]; then
JAVA_PATH=`dirname $JAVA_PATH 2>/dev/null`
JRE_HOME=`dirname $JAVA_PATH 2>/dev/null`
fi
if [ "x$JRE_HOME" = "x" ]; then
# XXX: Should we try other locations?
if [ -x /usr/bin/java ]; then
JRE_HOME=/usr
fi
fi
fi
if [ -z "$JAVA_HOME" -a -z "$JRE_HOME" ]; then
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 [ "$1" = "debug" ] ; then
if [ "$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 "$JAVA_HOME"/bin/javac ]; then
echo "The JAVA_HOME environment variable is not defined correctly"
echo "This environment variable is needed to run this program"
echo "NB: JAVA_HOME should point to a JDK not a JRE"
exit 1
fi
fi
fi
if [ -z "$BASEDIR" ]; then
echo "The BASEDIR environment variable is not defined"
echo "This environment variable is needed to run this program"
exit 1
fi
if [ ! -x "$BASEDIR"/bin/setclasspath.sh ]; then
if $os400; then
# -x will Only work on the os400 if the files are:
# 1. owned by the user
# 2. owned by the PRIMARY group of the user
# this will not work if the user belongs in secondary groups
eval
else
echo "The BASEDIR environment variable is not defined correctly"
echo "This environment variable is needed to run this program"
exit 1
fi
fi

# Don't override the endorsed dir if the user has set it previously
if [ -z "$JAVA_ENDORSED_DIRS" ]; then
# Set the default -Djava.endorsed.dirs argument
JAVA_ENDORSED_DIRS="$BASEDIR"/endorsed
fi

# OSX hack to CLASSPATH
JIKESPATH=
if [ `uname -s` = "Darwin" ]; then
OSXHACK="/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Classes"
if [ -d "$OSXHACK" ]; then
for i in "$OSXHACK"/*.jar; do
JIKESPATH="$JIKESPATH":"$i"
done
fi
fi

# Set standard commands for invoking Java.
_RUNJAVA="$JRE_HOME"/bin/java
if [ "$os400" != "true" ]; then
_RUNJDB="$JAVA_HOME"/bin/jdb
fi