JSP未找到bean中的屬性

Question

我的JSP提供的錯誤顯示它無法在DTO中找到屬性，但在DTO中屬性確實存在。下面是錯誤：

 
type Exception report 

message 

description The server encountered an internal error() that prevented it from fulfilling this request. 

    exception 

    org.apache.jasper.JasperException: An exception occurred processing JSP page /addPos.jsp at line 101 

    98:       
    99:        --%> 
    100: 
    101:        ${dt.date} 
    102: 
    103:       
    104:       

    Stacktrace: 
     org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505) 
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416) 
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342) 
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267) 
     javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
     org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390) 

    root cause 

    javax.el.PropertyNotFoundException: Property 'date' not found on type p1.dateDto 
     javax.el.BeanELResolver$BeanProperties.get(BeanELResolver.java:193) 
     javax.el.BeanELResolver$BeanProperties.access$400(BeanELResolver.java:170) 
     javax.el.BeanELResolver.property(BeanELResolver.java:279) 
     javax.el.BeanELResolver.getValue(BeanELResolver.java:60) 
     javax.el.CompositeELResolver.getValue(CompositeELResolver.java:54) 
     org.apache.el.parser.AstValue.getValue(AstValue.java:118) 
     org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186) 
     org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:935) 
     org.apache.jsp.addPos_jsp._jspx_meth_c_005fforEach_005f0(addPos_jsp.java:227) 
     org.apache.jsp.addPos_jsp._jspService(addPos_jsp.java:168) 
     org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) 
     javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374) 
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342) 
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267) 
     javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
     org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390) 

這裏是dateDto類：

package p1; 
import java.sql.Date; 

/** 
* 
* @author kk 
*/ 
public class dateDto 
{ 
    private Date date; 

    public dateDto() 
    { 
    } 

    public dateDto(Date date) 
    { 
     this.date =date; 
    } 


    public Date getDateDto() 
    { 
     return this.date ; 
    } 
} 

下面是dateDao：

package p1; 

/** 
* 
* @author kk 
*/ 
import java.sql.*; 
import java.util.*; 

public class dateDao { 

    private List<dateDto> dateList; 
    private String dbUrl = "jdbc:mysql://localhost/mvs_db"; 
    private String dbDriver = "com.mysql.jdbc.Driver"; 
    private String dbUser = "root"; 
    private String dbPwd = ""; 

    public dateDao() { 
    } 

    public List<dateDto> getDateList() { 
     dateList = new ArrayList<dateDto>(); 
     Connection con = null; 
     Statement stmt = null; 
     ResultSet rs = null; 

     try {//trying to load the database driver and establish a connection to the database 
      Class.forName(dbDriver);//loading the database driver 
      con = DriverManager.getConnection(dbUrl, dbUser, dbPwd);//establishing a connection to the database 
      //pw.println("connection established");//output if connection is established 
     } catch (Exception e) { 
      e.printStackTrace();//printing the exception error trace 
     } 

     try { 

      stmt = con.createStatement(); 
      rs = stmt.executeQuery("Select vote_date from voting_date"); 

      while (rs.next()) { 
       java.sql.Date date = rs.getDate("vote_date"); 
       dateDto s = new dateDto(date); 
       dateList.add(s); 
      } 

     } catch (Exception e) { 
      System.out.println(e); 
     } finally { 
      try { 
       if (con != null) { 
        con.close(); 
       } 
      } catch (Exception e) { 
       e.printStackTrace(); 
      } 
     } 

     return dateList; 
    } 
} 

實際上，我從MySQL數據庫中檢索日期類型的值和在下拉列表中顯示。

的JSP代碼如下：

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%> 
<jsp:useBean id="dtb" scope="session" class="p1.dateDao"/> 
<%-- 
    Document : addCamp 
    Created on : May 20, 2011, 11:28:31 AM 
    Author  : ken 
--%> 

<%@page contentType="text/html" pageEncoding="UTF-8"%> 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
    "http://www.w3.org/TR/html4/loose.dtd"> 

<html> 
    <head> 
     <style type="text/css"> 
      body { 
       background-color:#AFC7C7; 
       padding: 0; 
       margin: 0; 
      } 
      div.wrapper { 
       margin-left: 10%; 
       margin-right: 10%; 
       background-color:#6D7B8D; 
       height: 607px; 
       padding-top:0px; 
       border: thin solid #000000; 
      } 

      div#image{ 
       padding-top:1%; 
       padding-bottom:1%; 
      } 
      div#adminlogin{ 
       width:35%; 
       height:40%; 
       background-color:#AFC7C7; 
       border-width:thin; 
       border-style:solid; 
       border-color:#000000; 
       margin: 0 auto; 
       text-align:left; 
       overflow: hidden; 
       padding: 5px; 
      } 

      hr { 
       height:1px; 
       color:#000000; 
       background-color:#000000; 
       width:99%; 
       margin-left: 0 ; 
       margin-right: auto ; 
       border-style:solid; 
      } 

      .inputtext { 
       width: 200px; 
       height: 30px; 
       Font-Family:Arial; 
       Font-Size:18px 
      } 

     </style> 

     <script language="javascript" type="text/javascript"> 
      function clearText(field){ 

       if (field.defaultValue == field.value) field.value = ''; 
       else if (field.value == '') field.value = field.defaultValue; 

      } 

     </script> 
    </head> 
    <body> 
     <div class="wrapper"> 
      <div id="image"> 
       <p> 
        <img src="${pageContext.request.contextPath}/images/logo.gif" 
         alt="banner" 
         width=100% 
         height="100" 
         /></p> 
      </div><!--end of image div--> 
      <div id=adminlogin > 
       <p style="text-align:center">Adding Voting Position</p> 
       <hr/> 
       <form method=POST id="pos" action="${pageContext.request.contextPath}/getPos"> 
        <p/> 
        <%--The textfield for hostel name--%> 
        <label>Position<input type="text" id="pos" name="position" value="" class="inputtext" 
              onFocus="clearText(this)" onBlur="clearText(this)"/></label><br/> 
        <br/> 
        <label>Voting Date <select name="dates" size="1" id="pos" class="inputtext" 
               onFocus="clearText(this)" onBlur="clearText(this)"> 
         <c:forEach items="${dtb.dateList}" var="dt"> 
          <%--<option value="1"><c:out value="${cam.campnm}"/></option>--%> 

          <option>${dt.date}</option> 

         </c:forEach> 
         </select></label> 
         <br/> 
         <br/> 
        <input type="submit" value="Add" style="font-size:14pt; margin-left: 158px; height: 30px;"/> 

       </form> 
       <p STYLE="color : #E41B17;">${message}</p> 
       <c:remove var="message" scope="session" /> 



      </div><%--end of admin login div--%> 
      <p style="text-align: center"><a href=adminHome.jsp>Home</a> <a href=index.jsp>Logout</a></p> 
     </div> 
    </body> 
</html> 

可能是什麼問題呢？

Answer 1

你錯過了標準的制定者/吸氣劑dateDto

讓它

public class dateDto 
{ 
    private Date date; 

    public dateDto() 
    { 
    } 

    public dateDto(Date date) 
    { 
     this.date =date; 
    } 


    public Date getDate() 
    { 
     return this.date ; 
    } 

    public Date setDate(Date d) 
    { 
      this.date = d; 
    } 
} 

Answer 2

的問題是，你正在尋找物業date和你的財產實際上是名爲dateDto。