Servlet的主要功能是处理客户端的表单请求数据,在Servlet中首先对这些数据进行验证,可能会封装到JavaBean,接下来调用数据库的业务逻辑方法将数据保存或者进行其他操作,最后Servlet控制将响应结果返回给客户端;
在Servlet中获取表单信息主要是应用HttpServletRequest对象的getParameter()方法,若getParameter()方法尝试读取一个null值,执行时将会抛出一个java.lang.NULLPointerException的异常;
在Servlet中会根据客户端表单的method属性值来决定调用doXXX()方法,如果method属性值为POST,调用doPost()方法,反之调用doGet方法;
新建名为LoginServlet的Servlet类,在doPost()方法中获得请求信息
public class LoginServlet extends HttpServlet {
public void doPost(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{
request.setCharacterEncoding("utf-8");
String name=request.getParameter("name");
String pwd=request.getParameter("pwd");
String sex=request.getParameter("sex");
String age=request.getParameter("age");
String email=request.getParameter("email");
request.getRequestDispatcher("logininfo.jsp").forward(request, response);
}
public void doGet(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{
this.doPost(request, response);
}
}
index.jsp页面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="login" method="post">
<table align="center">
<tr>
<td>用户名:</td><td><input type="text" name="name"></td>
</tr>
<tr>
<td>密码:</td><td><input type="password" name="pwd"></td>
</tr>
<tr>
<td>性别:</td>
<td>
<input type="radio" name="sex" value="男">男
<input type="radio" name="sex" value="女">女
</td>
</tr>
<tr>
<td>年龄:</td><td><input type="text" name="age"></td>
</tr>
<tr>
<td>Email:</td><td><input type="text" name="email"></td>
</tr>
<tr>
<td colspan="2" align="center">
<input type="submit" value="注册"/><input type="reset" value="重置"/>
</tr>
</table>
</form>
</body>
</html>
logininfo.jsp页面
<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>用户注册信息</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<style type="text/css">
table{
font-size:12px;
font-family: 隶书;
color:gray;
border: 1px green solid;
}
</style>
</head>
<body>
<table align="center">
<tr>
<td>用户名:</td>
<td><%=request.getParameter("name")%></td>
</tr>
<tr>
<td>密码:</td>
<td><%=request.getParameter("pwd")%></td>
</tr>
<tr>
<td>性别:</td>
<td>
<%=request.getParameter("sex")%>
</td>
</tr>
<tr>
<td>年龄:</td>
<td><%=request.getParameter("age")%></td>
</tr>
<tr>
<td>Email:</td>
<td><%=request.getParameter("email")%></td>
</tr>
</table>
</body>
</html>
配置web.xml文件
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.cn.zj.Servlet.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>