linux下tomcat无法启动

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

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

#!/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-6-sun
export JRE_HOME=/usr/lib/jvm/java-6-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 "$JAVA_HOME"/bin/javac ]; then
      echo "The JAVA_HOME environment variable is not defined correctly"
      echo "This environment variable is needed to run this program"
      echo "NB: JAVA_HOME should point to a JDK not a JRE"
      exit 1
    fi
  fi
fi
if [ -z "$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

# Set the default -Djava.endorsed.dirs argument
JAVA_ENDORSED_DIRS="$BASEDIR"/endorsed

# Set standard CLASSPATH
if [ "$1" = "debug" -o "$1" = "javac" ] ; then
  CLASSPATH="$JAVA_HOME"/lib/tools.jar
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="$JAVA_HOME"/bin/jdb
fi
_RUNJAVAC="$JAVA_HOME"/bin/javac