页面没反应java.lang.NullPointerException
<%@ page language="java" import="java.util.*,java.text.*" contentType="text/html; charset=utf-8"%>
<%
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>My JSP 'userinfo.jsp' starting page</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">
.title{
width: 30%;
background-color: #CCC;
font-weight: bold;
}
.content{
width:70%;
background-color: #CBCFE5;
}
</style>
</head>
<body>
<h1>用户信息</h1>
<hr>
<center>
<jsp:useBean id="regUser" class="entity.Users" scope="session"/>
<table width="600" cellpadding="0" cellspacing="0" border="1">
<tr>
<td class="title">用户名：</td>
<td class="content"> <jsp:getProperty name="regUser" property="username"/></td>
</tr>
<tr>
<td class="title">密码：</td>
<td class="content"> <jsp:getProperty name="regUser" property="mypassword"/></td>
</tr>
<tr>
<td class="title">性别：</td>
<td class="content"> <jsp:getProperty name="regUser" property="gender"/></td>
</tr>
<tr>
<td class="title">E-mail：</td>
<td class="content"> <jsp:getProperty name="regUser" property="email"/></td>
</tr>
<tr>
<td class="title">出生日期：</td>
<td class="content">
<%
SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日");
String date = sdf.format(regUser.getBirthday());
%>
<%=date%>
</td>
</tr>
<tr>
<td class="title">爱好：</td>
<td class="content">
<%
String[] favorites = regUser.getFavorites();
for(String f:favorites)
{
%>
<%=f%>
<%
}
%>
</td>
</tr>
<tr>
<td class="title">自我介绍：</td>
<td class="content"> <jsp:getProperty name="regUser" property="introduce"/></td>
</tr>
<tr>
<td class="title">是否介绍协议：</td>
<td class="content"> <jsp:getProperty name="regUser" property="flag"/></td>
</tr>
</table>
</center>
</body>
</html>package servlet;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import entity.Users;
public class RegServlet extends HttpServlet {
/**
* Constructor of the object.
*/
public RegServlet() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
Users u = new Users();
String username;
String mypassword;
String gender;
String email;
String introduce;
String isAccept;
Date birthday;
String[] favorites;
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
try {
username = request.getParameter("username");
mypassword = request.getParameter("mypassword");
gender = request.getParameter("gender");
email = request.getParameter("email");
introduce = request.getParameter("introduce");
if (request.getParameterValues("isAccept")!=null) {
isAccept = request.getParameter("isAccept");
}else {
isAccept = "false";
}
birthday = sdf.parse(request.getParameter("birthday"));
//用来获取多个复选按钮的值
favorites = request.getParameterValues("favorites");
u.setUsername(username);
u.setMypassword(mypassword);
u.setGender(gender);
u.setEmail(email);
u.setIntroduce(introduce);
if (isAccept.equals("true")) {
u.setFlag(true);
}else {
u.setFlag(false);
}
u.setBirthday(birthday);
u.setFavorites(favorites);
//把注册成功的用户对象保存到session中
request.getSession().setAttribute("regUser", u);
//跳转到注册成功页面
request.getRequestDispatcher("../userinfo.jsp").forward(request,response);
} catch(Exception ex){
ex.printStackTrace();
}
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}package servlet;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import entity.Users;
public class RegServlet extends HttpServlet {
/**
* Constructor of the object.
*/
public RegServlet() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
Users u = new Users();
String username;
String mypassword;
String gender;
String email;
String introduce;
String isAccept;
Date birthday;
String[] favorites;
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
try {
username = request.getParameter("username");
mypassword = request.getParameter("mypassword");
gender = request.getParameter("gender");
email = request.getParameter("email");
introduce = request.getParameter("introduce");
if (request.getParameterValues("isAccept")!=null) {
isAccept = request.getParameter("isAccept");
}else {
isAccept = "false";
}
birthday = sdf.parse(request.getParameter("birthday"));
//用来获取多个复选按钮的值
favorites = request.getParameterValues("favorites");
u.setUsername(username);
u.setMypassword(mypassword);
u.setGender(gender);
u.setEmail(email);
u.setIntroduce(introduce);
if (isAccept.equals("true")) {
u.setFlag(true);
}else {
u.setFlag(false);
}
u.setBirthday(birthday);
u.setFavorites(favorites);
//把注册成功的用户对象保存到session中
request.getSession().setAttribute("regUser", u);
//跳转到注册成功页面
request.getRequestDispatcher("../userinfo.jsp").forward(request,response);
} catch(Exception ex){
ex.printStackTrace();
}
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
这样怎么解决空指针？
AquanGeek1回答
-
言曌博客liuyanzhao_com
这种问题，还是自己思考吧，多折腾几次，有好处
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