在Servlet中处理表单提交的数据

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；
在这里插入图片描述

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>

在Servlet中处理表单提交的数据

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