\webapps\test 路径下ThreeParams.html:
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type" />
<title>TreeParams</title>
</head>
<body>
<form method="get" onsubmit="return true" name="form1" action="/test/tp">
<table align="center" border="2" width="500">
<tr>
.......
web.xml 正确配置：
<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">
<servlet>
<servlet-name>TP</servlet-name>
<servlet-class>ThreeParams</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>TP</servlet-name>
<url-pattern>/tp</url-pattern>
</servlet-mapping>
</web-app>
这个servlet的路径为：http://localhost:8080/test/tp
总结：action这里填的并不是web.xml里的映射路径，而是URL+web.xml的配置路径。
