老师，出现了错误[ The markup in the document following the root element must be well-formed ]

<?xml version="1.0" encoding="UTF-8"?>

<servlet>

<servlet-name>我的第一个servlet</servlet-name>

<servlet-class>servlet.Hello_servlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>我的第一个servlet</servlet-name>

<url-pattern>/servlet/Hello_servlet</url-pattern>

</servlet-mapping>