第一点 servlect 注册
在web.xml文件中写入以下代码进行注册servlect
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" id="WebApp_ID" version="4.0">
<display-name>Day02jsp</display-name>
<servlet>
<servlet-name>ReadParams</servlet-name>
<servlet-class>com.servlet.ReadParams</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ReadParams&