如何在Linux操作系统定时重启Tomcat服务？

背景：

正常情况下启动和关闭tomcat程序命令如下：

/application/tomcat/bin/startup.sh
/application/tomcat/bin/shutdown.sh

但是定时任务情况下无法启动tomcat程序，提示没有java环境变量，提示crontab中不需要加/bin/sh /application/tomcat/bin/startup.sh因为tomcat程序本身就是可执行文件，如果本身不是可执行文件

需要加/bin/bash。

具体定时任务和报错日志如下：

[root@szxjdw01-tomcat-50 scripts]# crontab -e
#time sync by jeremy at 2018-08-13
*/5 * * * * /usr/sbin/ntpdate ntp1.aliyun.com >/dev/null 2>&1
14 09 * * * /application/tomcat/bin/shutdown.sh >>/tmp/tomcat.log
01 00 * * * /application/tomcat/bin/startup.sh >>/tmp/tomcat.log

日志报错提示没有java环境变量
[root@szxjdw01-tomcat-50 scripts]# cat /tmp/tomcat.log
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
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
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

那么如何才能在linux系统中定时重启tomcat服务呢？请看如下：

Linux操作系统定时重启Tomcat服务的方法如下：

1、编写tomcat_shutdown.sh：

[root@szxjdw01-tomcat-50 ~]# cat /server/scripts/tomcat_shutdown.sh
#!/bin/bash
#set java environment
export JAVA_HOME=/usr/java/jdk
export CLASSPATH=$CLASSPATH:$JAVA_HOME/lib:$JAVA_HOME/jre/lib
export PATH=$JAVA_HOME/bin:$JAVA_HOME/jre/bin:$PATH
echo "========begin stop the tomcat========"
'/application/tomcat/bin/shutdown.sh'

2、编写tomcat_startup.sh：

[root@szxjdw01-tomcat-50 ~]# cat /server/scripts/tomcat_startup.sh
#!/bin/bash
#set java environment
export JAVA_HOME=/usr/java/jdk
export CLASSPATH=$CLASSPATH:$JAVA_HOME/lib:$JAVA_HOME/jre/lib
export PATH=$JAVA_HOME/bin:$JAVA_HOME/jre/bin:$PATH
echo "========begin stop the tomcat========"
'/application/tomcat/bin/startup.sh'

3、测试脚本是否ok

[root@szxjdw01-tomcat-50 ~]# cd /server/scripts/
[root@szxjdw01-tomcat-50 scripts]# netstat -lntup|grep java    #查看当前tomcat监听的端口
tcp        0      0 ::ffff:127.0.0.1:8005       :::*                        LISTEN      4055/java
tcp        0      0 :::8009                 :::*                        LISTEN      4055/java
tcp        0      0 :::8080                 :::*                        LISTEN      4055/java
[root@szxjdw01-tomcat-50 scripts]# ll
total 12
drwxr-x---. 2 root root 4096 Sep 18 10:17 logs
-rw-r--r--. 1 root root  262 Sep 18 10:15 tomcat_shutdown.sh
-rw-r--r--. 1 root root  261 Sep 18 10:16 tomcat_startup.sh
[root@szxjdw01-tomcat-50 scripts]# sh tomcat_shutdown.sh     #关闭tomcat服务
========begin stop the tomcat========
Using CATALINA_BASE:   /application/tomcat
Using CATALINA_HOME:   /application/tomcat
Using CATALINA_TMPDIR: /application/tomcat/temp
Using JRE_HOME:        /usr/java/jdk
Using CLASSPATH:       /application/tomcat/bin/bootstrap.jar:/application/tomcat/bin/tomcat-juli.jar
[root@szxjdw01-tomcat-50 scripts]# netstat -lntup|grep java     #继续查看tomcat服务没有监听任务端口了
[root@szxjdw01-tomcat-50 scripts]# sh tomcat_startup.sh         #再次启动tomcat服务
========begin stop the tomcat========
Using CATALINA_BASE:   /application/tomcat
Using CATALINA_HOME:   /application/tomcat
Using CATALINA_TMPDIR: /application/tomcat/temp
Using JRE_HOME:        /usr/java/jdk
Using CLASSPATH:       /application/tomcat/bin/bootstrap.jar:/application/tomcat/bin/tomcat-juli.jar
Tomcat started.
[root@szxjdw01-tomcat-50 scripts]# netstat -lntup|grep java    #再次查看发现tomcat端口8080已启动了，一般情况下 tomcat的8005端口会延迟启动，稍等1-2分钟后才启动8005端口
tcp        0      0 ::ffff:127.0.0.1:8005       :::*                        LISTEN      4221/java
tcp        0      0 :::8009                     :::*                        LISTEN      4221/java
tcp        0      0 :::8080                     :::*                        LISTEN      4221/java

4、在linux系统终端中，输入命令“crontab -e”：

    在vi操作界面，输入：

[root@szxjdw01-tomcat-50 ~]# crontab -e
#time sync by jeremy at 2018-08-13
*/5 * * * * /usr/sbin/ntpdate ntp1.aliyun.com >/dev/null 2>&1
01 13 * * * /bin/bash /server/scripts/tomcat_shutdown.sh >>/tmp/tomcat.log
02 13 * * * /bin/bash /server/scripts/tomcat_startup.sh >>/tmp/tomcat.log

    实时查看日志：

[root@szxjdw01-tomcat-50 ~]# tailf /tmp/tomcat.log
========begin stop the tomcat========
========begin stop the tomcat========
Tomcat started.

    端口也是从无到有了

[root@szxjdw01-tomcat-50 scripts]# netstat -lntup|grep java   #tomcat服务启动时，查看当前tomcat监听的端口
tcp        0      0 ::ffff:127.0.0.1:8005       :::*                        LISTEN      4055/java
tcp        0      0 :::8009                 :::*                        LISTEN      4055/java
tcp        0      0 :::8080                 :::*                        LISTEN      4055/java
[root@szxjdw01-tomcat-50 scripts]# netstat -lntup|grep java    #tomcat服务关闭后，查看tomcat监听端口没有了
[root@szxjdw01-tomcat-50 scripts]# netstat -lntup|grep java    #tomcat服务启动时后，再次查看发现tomcat端口8080已启动了，一般情况下 tomcat的8005端口会延迟启动，稍等1-2分钟后才启动8005端口
tcp        0      0 ::ffff:127.0.0.1:8005       :::*                        LISTEN      4221/java
tcp        0      0 :::8009                     :::*                        LISTEN      4221/java
tcp        0      0 :::8080                     :::*                        LISTEN      4221/java

如上说明定时任务重启tomcat服务ok了。

5、使用“crontab -l”命令，可以查看定时任务的设置情况。

[root@szxjdw01-tomcat-50 scripts]# crontab -l
#time sync by jeremy at 2018-08-13
*/5 * * * * /usr/sbin/ntpdate ntp1.aliyun.com >/dev/null 2>&1
55 10 * * * /bin/bash /server/scripts/tomcat_shutdown.sh >>/tmp/tomcat.log
56 10 * * * /bin/bash /server/scripts/tomcat_startup.sh >>/tmp/tomcat.log

6、如果定时任务不执行可以通过查看日志：

[root@szxjdw01-tomcat-50 mail]# less /var/log/cron
Sep 18 10:55:01 localhost CROND[4449]: (root) CMD (/bin/bash /server/scripts/tomcat_shutdown.sh >>/tmp/tomcat.log)
Sep 18 10:55:36 localhost crontab[4497]: (root) LIST (root)
Sep 18 10:55:37 localhost crontab[4499]: (root) LIST (root)
Sep 18 10:55:37 localhost crontab[4501]: (root) LIST (root)
Sep 18 10:55:51 localhost crontab[4503]: (root) LIST (root)
Sep 18 10:55:52 localhost crontab[4505]: (root) LIST (root)
Sep 18 10:56:01 localhost CROND[4511]: (root) CMD (/bin/bash /server/scripts/tomcat_startup.sh >>/tmp/tomcat.log)