servlet配置文件web.xml中<url-pattern>的问题？

Posted 2023-03-17

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项目名：ServletDemo
servlet文件：
package com.servlet.session.Demo2;

public class LoginServlet extends HttpServlet

public LoginServlet()
super();

public void destory()
super.destroy();

public void doGet(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException
doPost(request,response);

public void doPost(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException
String username = request.getParameter("username");
String passwd = request.getParameter("passwd");
if(username.equals("jb-aptech")&&passwd.equals("12345"))
HttpSession session= request.getSession(true);
session.setAttribute("username", username);
session.setAttribute("passwd", passwd);
RequestDispatcher view = request.getRequestDispatcher("InfoServlet");
view.forward(request, response);
else

response.sendRedirect("../login.jsp");

public void init() throws ServletException

jsp文件：
<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>

<! DOCTYPE html PUBLIC"-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>登录页面</title>

<script type="text/javascript">
function RegisterSubmit()
with(document.Register)
var loginname= username.value;
var loginpasswd= passwd.value;
if(loginname==null|| loginname=="")
alert("请填写用户名");
else if(loginpasswd==null|| loginpasswd=="")
alert("请填写密码");
else
document.Register.submit();

</script>
</head>
<body>
<from action="servlet/LofinServlet" name="Register" method="post">
<center>
<table width="600" borfer="0" bacolor="#8FBC8F">
<tr>
<td align="right">用户名:</td>
<td align="left"><input type="text" name="username" style="widty:120px"/></td>
</tr>
<tr>
<td align="right">密码:</td>
<td align="left"><input type="password" name="passwd" style="widty:120px"/></td>
</tr>
<tr>
<td align="right"><input type="button" value="提交" onClisk="RegisterSubmit()"> </td>
<td align="left"><input type="reset" value="重置" /></td>
</tr>
</table>
</center>
</body>
</html>
web.xml文件：
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.servlet.session.Demo2.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/servlet/LoginServlet</url-pattern>
</servlet-mapping>

问题：启动tomcat后，在网页中键入http://localhost:8080时，正常。但是再键入http://localhost:8080/ServlerDemo/servlet/LoginServlet 时，怎么出现404错误。是不是我的地址输入错误，正确的地址是哪样的。
怎么我改了之后，还是同样的问题。

<from action="servlet/LofinServlet" name="Register" method="post">
写错了应该是f--->g :LoginServlet
工程里面的webinfo---》改名为WEB-INF。重新部署试试吧
你的地址输入应该是正确的。追问

怎么我改了之后，还是同样的问题?

追答

兄弟，你的应用名字是ServletDemo。
所以你的URL应该是http://localhost:8080/ServletDemo/servlet/LoginServlet
其中你又拼写错了。

参考技术A WebInfo没见过啊，应该是WEB-INF吧。参考技术B 你键入网址键入错了，因为你的<url-pattern>是：<url-pattern>/servlet/LoginServlet</url-pattern>

所以应该键入http://localhost:8080/servlet/LoginServlet 参考技术C 把<url-pattern>/servlet/LoginServlet</url-pattern> 里面改成<url-pattern>/LoginServlet</url-pattern>
，jsp页面action项也改成action=“LoginServlet” 参考技术D WebInfo没见过第5个回答 2020-04-01 <from
action="servlet/LofinServlet"
name="Register"
method="post">
写错了应该是f--->g
:LoginServlet
工程里面的webinfo---》改名为WEB-INF。重新部署试试吧
你的地址输入应该是正确的。

web.xml

在Tomcat/conf下有一个web.xml文件，当Tomcat中所有web应用实例化时都会读取该配置文件，然后读取每个web应用自己的配置文件（/WEB-INF/web.xml）。

conf/web.xml作出以下配置：

//处理未映射到其他servlet的请求
    <servlet>
        <servlet-name>default</servlet-name>
        <servlet-class>org.apache.catalina.servlets.DefaultServlet</servlet-class>
        <init-param>
            <param-name>debug</param-name>
            <param-value>0</param-value>
        </init-param>
        <init-param>
            <param-name>listings</param-name>
            <param-value>false</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
//jsp页面编译和执行servlet
    <servlet>
        <servlet-name>jsp</servlet-name>
        <servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
        <init-param>
            <param-name>fork</param-name>
            <param-value>false</param-value>
        </init-param>
        <init-param>
            <param-name>xpoweredBy</param-name>
            <param-value>false</param-value>
        </init-param>
        <load-on-startup>3</load-on-startup>
    </servlet>
//映射关系
    <!-- The mapping for the default servlet -->
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <!-- The mappings for the JSP servlet -->
    <servlet-mapping>
        <servlet-name>jsp</servlet-name>
        <url-pattern>*.jsp</url-pattern>
        <url-pattern>*.jspx</url-pattern>
    </servlet-mapping>

//会话设置
    <session-config>
        <session-timeout>30</session-timeout>
    </session-config>
//MIME类型映射
    <mime-mapping>
        <extension>123</extension>
        <mime-type>application/vnd.lotus-1-2-3</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>3dml</extension>
        <mime-type>text/vnd.in3d.3dml</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>3ds</extension>
        <mime-type>image/x-3ds</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>3g2</extension>
        <mime-type>video/3gpp2</mime-type>
    </mime-mapping>
...
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