shell代码（注意，一定要在VIM中编辑，否则执行会有问题）

port=$1
if [ ! -n "$port" ];then
        echo "please enter the args port!"
        exit
fi

service_name=$2

nc -w2 localhost $port

if [ $? != 0 ];then
        echo '【'`date +"%Y-%m-%d %H:%M:%S"`'】检测到端口【'${port}'】已经关闭，该服务重新启动'>>/root/monitor_log.log
        sh $2
	exit
fi

执行定时任务 每十秒执行一次

crontab -e
* * * * * sleep 10; /root/port_monitor.sh 90  /var/dbstar/program/dmail-tomcat/bin/startup.sh

添加邮件功能

vim /etc/mail.rc

set from=xxx@xxx.com.cn smtp=mail.xxx.com.cn
set smtp-auth-user=xxx@xxx.com.cn smtp-auth-password=123456 smtp-auth=login

echo "the port ${port} is down,the server is  restart ${port} port!!"|mail -s "port ${port}/${service_name} is down!" xxx@xxx.com.cn

启动tomcat时乱码解决方案

在catalina.sh中添加如下代码即可

JAVA_OPTS="-Dfile.encoding=utf-8"

最终代码(shell)

port=$1
if [ ! -n "$port" ];then
        echo "please enter the args port!"
        exit
fi

service_name=$2

nc -w2 localhost $port

if [ $? != 0 ];then
        echo '【'`date +"%Y-%m-%d %H:%M:%S"`'】检测到端口【'${port}'】已经关闭，该服务重新启动'>>/root/monitor_log.log
        if [ -n "$service_name" ];then
                sh $2
        fi
        if [ ! -n "$service_name" ];then
                mkdir /tmp/portmonitor/ -p
                touch /tmp/portmonitor/${port}.log
                flag=$(cat /tmp/portmonitor/${port}.log)
                if [ ! -n "$flag" ] || [  "1" != "$flag" ];then
                        echo '1'>/tmp/portmonitor/${port}.log
                fi
        fi
        echo "the port ${port} is down,the server is  restart ${port} port!!"|mail -s "port ${port}/${service_name} is down!" xxx@xxx.com.cn
        exit
fi