在context中加上 reloadable=“true” 即可

位置：tomcat->conf->context.xml

原代码：

<?xml version="1.0" encoding="UTF-8"?>
<Context>
 	<WatchedResource>WEB-INF/web.xml</WatchedResource>
    <WatchedResource>${catalina.base}/conf/web.xml</WatchedResource>
</Context>

更改后的代码：

<?xml version="1.0" encoding="UTF-8"?>
<Context reloadable="true">
 	<WatchedResource>WEB-INF/web.xml</WatchedResource>
    <WatchedResource>${catalina.base}/conf/web.xml</WatchedResource>
</Context>