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页面没反应java.lang.NullPointerException

页面没反应java.lang.NullPointerException

AquanGeek 2017-08-27 19:07:51
<%@ 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">&nbsp;<jsp:getProperty name="regUser" property="username"/></td>         </tr>         <tr>           <td class="title">密码:</td>           <td class="content">&nbsp;<jsp:getProperty name="regUser" property="mypassword"/></td>         </tr>         <tr>           <td class="title">性别:</td>           <td class="content">&nbsp;<jsp:getProperty name="regUser" property="gender"/></td>         </tr>         <tr>           <td class="title">E-mail:</td>           <td class="content">&nbsp;<jsp:getProperty name="regUser" property="email"/></td>         </tr>         <tr>           <td class="title">出生日期:</td>           <td class="content">&nbsp;             <%                 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">&nbsp;             <%                 String[] favorites = regUser.getFavorites();                for(String f:favorites)                {             %>                 <%=f%> &nbsp;&nbsp;             <%                 }             %>           </td>         </tr>         <tr>           <td class="title">自我介绍:</td>           <td class="content">&nbsp;<jsp:getProperty name="regUser" property="introduce"/></td>         </tr>         <tr>           <td class="title">是否介绍协议:</td>           <td class="content">&nbsp;<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?
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言曌博客liuyanzhao_com

TA贡献164条经验 获得超117个赞

这种问题,还是自己思考吧,多折腾几次,有好处

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反对 回复 2017-08-27
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