从数据库中检索表：javax.el.PropertyNotFoundException答案

【问题标题】：Retrieving a table from database: javax.el.PropertyNotFoundException从数据库中检索表：javax.el.PropertyNotFoundException
【发布时间】：2013-11-26 10:45:43
【问题描述】：

我想从数据库中检索整个表并将其显示到我的 jsp 页面中，但出现错误

我的 StaffBean。 java是

package com.staff.bean;
import java.util.Date;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;


 public class StaffBean {

    private String date;
    private int workload;
    private int hourId;
    private int daysId;
    private int staffId;
    private String StaffName;
    private String ActiveORInactive;
    private String Stafftype;
    private String subcode;
    private boolean valid = false;

public String getdate() {
   // DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
 //   Date date = new Date();
    SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd"); // your template here
    java.util.Date dateStr = null;
    try {
        dateStr = formatter.parse(date);
    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    java.sql.Date dateDB = new java.sql.Date(dateStr.getTime());
    return formatter.format(dateDB);
}
public void setdate(String date){
    this.date=date;
}
public int gethourId() {
    return hourId;
}
public void sethourId(int hourId) {
    this.hourId = hourId;
}
public int getdaysId() {
    return daysId;
}
public void setdaysId(int daysId) {
    this.daysId = daysId;
}
public int getworkload() {
    return hourId;
}
public void setworkload(int workload) {
    this.workload = workload;
}
    public int getstaffId() {
        return staffId;
    }
    public void setstaffId(int staffId) {
        this.staffId = staffId;
    }
    public String getStaffName() {
        return StaffName;
    }
    public void setStaffName(String StaffName) {
        this.StaffName = StaffName;
    }
    public String ActiveORInactive() {
        return ActiveORInactive;
    }
    public void setActiveORInactive(String ActiveORInactive) {
        this.ActiveORInactive = ActiveORInactive;
    }

    public String getStafftype() {
        return Stafftype;
    }
    public void setStafftype(String Stafftype) {
        this.Stafftype = Stafftype;
    }
    public String getsubcode() {
        return Stafftype;
    }
    public void setsubcode(String subcode) {
        this.subcode = subcode;
    }

    public boolean isValid() {
        return valid;
    }
    public void setValid(boolean valid) {
        this.valid = valid;
    }


}

我的 GetAllDetailDAO.java 是

 package com.staff.DAO;
 import java.sql.Connection;
 import java.sql.ResultSet;
  import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.ArrayList;
 import java.util.List;

  import com.staff.bean.StaffBean;
  import com.staff.DB.ConnectionProvider;
  public class GetAllDetailDAO {

    Connection con;
    Statement stmt;
    private int noOfRecords;

    public List<StaffBean> viewAllStaff(int offSet, int noOfRecords){

        List<StaffBean> list = new ArrayList<StaffBean>();
        StaffBean _staffBean;
        try {
            con = ConnectionProvider.getConnection();
            stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery("select SQL_CALC_FOUND_ROWS * from  tblstaffdetails limit "+offSet+","+noOfRecords);
                    //+offSet+","+noOfRecords);
            //SQL_CALC_FOUND_ROWS
            while(rs.next()){
                _staffBean = new StaffBean();
                _staffBean.setStaffName(rs.getString("StaffName"));
                _staffBean.setstaffId(rs.getInt("staffId"));
                _staffBean.setActiveORInactive(rs.getString("ActiveORInactive"));
                _staffBean.setStafftype(rs.getString("Stafftype"));
                list.add(_staffBean);
            }
            rs.close();          
            rs = stmt.executeQuery("SELECT FOUND_ROWS()");
            if(rs.next())
             this.noOfRecords = rs.getInt(1);

        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


        return list;

    }
    public int getNoOfRecords() {
      return noOfRecords;
    }
}

连接提供者包 com.staff.DB;

  import java.sql.*;

public class ConnectionProvider {
    static Connection con;
    static String url;

    public static Connection getConnection() throws SQLException{
        try{ 
              Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/StaffAllocation","root", "success");
        }catch(ClassNotFoundException cnf){
            cnf.printStackTrace();
        }

        return con;

    }

}

而我的 GetAllDetailServlet.java 是

  package com.staff.servlet;
  import java.io.IOException;
  import java.util.List;
  import java.sql.*;

  import javax.servlet.RequestDispatcher;
  import javax.servlet.ServletException;
  import javax.servlet.annotation.WebServlet;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;

  import com.staff.bean.StaffBean;
  import com.staff.DAO.GetAllDetailDAO;
  import com.staff.DB.*;

  @WebServlet("/GetAllDetailServlet")
    public class GetAllDetailServlet extends HttpServlet{




/**
 * Servlet implementation class GetAllDetailsServlet
 */


    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public GetAllDetailServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub

        int page = 1;
        int recordsPerPage = 4;
        if(request.getParameter("page") != null)
            page = Integer.parseInt(request.getParameter("page"));
            GetAllDetailDAO allDetailDAO = new GetAllDetailDAO();
            List<StaffBean> list  = allDetailDAO.viewAllStaff((page-1)*recordsPerPage, recordsPerPage);
        int noOfRecords = allDetailDAO.getNoOfRecords();
        int noOfPages = (int) Math.ceil(noOfRecords * 1.0 / recordsPerPage);
            request.setAttribute("staffList", list);
        request.setAttribute("noOfPages", noOfPages);
        request.setAttribute("currentPage", page);
            RequestDispatcher view = request.getRequestDispatcher("jsp/displayAllDetail.jsp");
            view.forward(request, response);

        }
        }

我的 DisplayAllDetail.jsp 是

  <html>
  <head>
   <link rel="stylesheet" type="text/css" href="css/style.css"/>
   <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
   <title> :: All Details</title>
  </head>
  <body>
  <fieldset>
   <table border="1" cellpadding="4" cellspacing="4" align="center">
<tr>
<th>staffId</th>
    <th>StaffName</th>
    <th>ActiveORInactive</th>
    <th>Stafftype</th>
    <c:forEach var="_staffBean" items="${staffList}">
        <tr>
            <td>${_staffBean.staffId}</td>
            <td>${_staffBean.StaffName}</td>
            <td>${_staffBean.ActiveORInactive}</td>
            <td>${_staffBean.Stafftype}</td>        
        </tr>
    </c:forEach>
</tr>
    </table>
    <c:if test="${currentPage != 1}">
<td><a href="getAll.do?method=get&page=${currentPage - 1}">Prev</a></td>
    </c:if>
    <table border="1" cellpadding="5" cellspacing="5" align="center">
<tr>
    <c:forEach begin="1" end="${noOfPages }" var="i">
        <c:choose>
            <c:when test="${currentPage eq i }">
                <td>${i}</td>
            </c:when>
            <c:otherwise>
                <td><a href="getAll.do?method=get&page=${i}">${i}</a></td>
            </c:otherwise>
        </c:choose>
    </c:forEach>
</tr>
</table>
<c:if test="${currentPage lt noOfPages }">
<td><a href="getAll.do?method=get&page=${currentPage+1 }">Next</a></td>
</c:if>
</fieldset>
</body>
</html>

我的错误是

  HTTP Status 500 - An exception occurred processing JSP page /jsp/displayAllDetail.jsp at line 22
  type Exception report

  message An exception occurred processing JSP page /jsp/displayAllDetail.jsp at line 22

  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 /jsp/displayAllDetail.jsp at line 22

19:         <c:forEach var="_staffBean" items="${staffList}">
20:             <tr>
21:                 <td>${_staffBean.staffId}</td>
22:                 <td>${_staffBean.StaffName}</td>
23:                 <td>${_staffBean.ActiveORInactive}</td>
24:                 <td>${_staffBean.Stafftype}</td>        
25:             </tr>

堆栈跟踪： org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334) javax.servlet.http.HttpServlet.service(HttpServlet.java:728) com.staff.servlet.GetAllDetailServlet.doGet(GetAllDetailServlet.java:56) javax.servlet.http.HttpServlet.service(HttpServlet.java:621) javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

根本原因

    javax.el.PropertyNotFoundException: Property 'StaffName' not found on type   com.staff.bean.StaffBean
javax.el.BeanELResolver$BeanProperties.get(BeanELResolver.java:237)
javax.el.BeanELResolver$BeanProperties.access$400(BeanELResolver.java:214)
javax.el.BeanELResolver.property(BeanELResolver.java:325)
javax.el.BeanELResolver.getValue(BeanELResolver.java:85)
org.apache.jasper.el.JasperELResolver.getValue(JasperELResolver.java:104)
org.apache.el.parser.AstValue.getValue(AstValue.java:183)
org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:185)
org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:1026)
org.apache.jsp.jsp.displayAllDetail_jsp._jspx_meth_c_005fforEach_005f0(displayAllDetail_jsp.java:157)
org.apache.jsp.jsp.displayAllDetail_jsp._jspService(displayAllDetail_jsp.java:99)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
com.staff.servlet.GetAllDetailServlet.doGet(GetAllDetailServlet.java:56)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

注意 Apache Tomcat/7.0.42 日志中提供了根本原因的完整堆栈跟踪。

【问题讨论】：

不要在标题中寻求帮助 - 在这里提出问题的每个人都希望得到答案。
在 getdate() 中，您将日期字符串解析为日期，然后再次将其格式化回字符串？？？？我真的不认为你想那样做！
NickJ，请帮我解决我的错误。我想检索一个表格并显示它，你能帮忙吗？
请用您所做的代码更改更新您的问题。我看不出还有什么问题。
我没有做太多的改变。唯一的问题是表格没有显示出来。

标签： java mysql jsp servlets

【解决方案1】：

尝试声明

    private String staffName;
    private String activeORInactive;
    private String stafftype;

而不是大写字母。

建议你关注Java Code convertions

【讨论】：

但是我已经创建了以大写字母开头的列的名称。如果我将它们编辑成更小的大小写会有什么变化？
你是如何映射你的数据库的？你在使用 OpenJpa，Hibernate 吗？如何初始化 ConnectionProvider？
对不起.. 我现在将我的连接提供商包括在我的问题中
我假设您使用的是 Hibernate。 JavaObject 属性名和列名彼此无关。只有你正在使用的映射（主要是 Hibernate 的 porpuse，让你忘记数据库名称，只使用面向对象的编程）在你的 java 对象中，你应该遵循约定，js 不会有问题
如果你是编程的初学者，并且你正在使用 Hibernate，我会劝阻你。 Hibernate 只适合高级程序员。我建议你改为学习 JDBC。

【解决方案2】：

在 Blanca Hdez 的正确答案的基础上，更改 JSP，使 staffName 的大小写正确：

<td>${_staffBean.StaffName}</td>

应该是：

<td>${_staffBean.staffName}</td>

注意“staffName”的小写“s”——非常重要！

【讨论】：

你是否也听从了布兰卡·赫德兹的建议？
是的。我试着转换成小写字母。请检查我的jsp页面。错误在于说明 c:forEach var="_staffBean" items="${staffList}"
应该赋予var什么值？必须用 _staffBean 替换什么