我在 StackOverflow 上发现了其他类似/问题，我尝试按照他们的解决方案解决我的问题，但我无法弄清楚我做错了什么。我需要将列表从 servlet 传递到 JSP 页面。
这是 Servlet:
package controller;
import dao.DAOFactory;
import dao.interfaces.RoleDAO;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
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 model.Role;
/**
*
* @author realnot
*/
@WebServlet("/Dashboard")
public class Dashboard extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
// Prepare messages.
Map<String, String> messages = new HashMap<String, String>();
req.setAttribute("messages", messages);
// Obtain DAOFactory.
DAOFactory crm = DAOFactory.getInstance("crm.jdbc");
if (crm == null) {
messages.put("dao", "DAOFactory not obtainerd: " + crm);
}
// Obtain RoleDAO.
RoleDAO roleDAO = crm.getRoleDAO();
if (roleDAO == null) {
messages.put("dao", "RoleDAO not obtained: " + roleDAO);
}
List<Role> roles = roleDAO.list();
req.setAttribute("roleList", roles);
RequestDispatcher rd = getServletContext().getRequestDispatcher("/pages/Dashboard.jsp");
rd.forward(req, res);
}
}
这是 JSP 页面:
<!DOCTYPE html>
<html>
<head>
<title>CRM - Customer Relationship Management</title>
<link rel="stylesheet" type="text/css" href="../css/reset.css" />
<link rel="stylesheet" type="text/css" href="../css/style.css" />
<link rel="stylesheet" type="text/css" href="../css/menu.css" />
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
</head>
<body>
<div id="container">
<div id="header">Header</div>
<div id="page" class="grid_24">
<div id="nav" class="grid_6">
<%@include file="include/navigation.html" %>
</div>
<div id="next-meetings" class="grid_6 content">
<h3>Next Meetings</h3>
<c:forEach items="${roleList}" var="role">
<c:out value="${role.role_id}"></c:out>
<c:out value="${role.role_name}"></c:out>
</c:forEach>
</div>
<div id="business-proposals" class="grid_6 content">
<h3>Business Proposals</h3>
</div>
<div id="personal-notes" class="grid_6 content">
<h3>Personal Notes</h3>
</div>
</div>
<div id="footer">Footer</div>
</div>
</body>
</html>
模型:
package model;
import java.io.Serializable;
public class Role implements Serializable {
// Constants ------------------------------------------------------
private static final long serialVersionUID = 1L;
// Properties -----------------------------------------------------
private Integer role_id;
private String role_name;
private String role_desc;
// Getters/setters ------------------------------------------------
public Integer getRoleID() { return this.role_id; }
public String getRoleName() { return this.role_name; }
public String getRoleDesc() { return this.role_desc; }
public void setRoleID(Integer value) { this.role_id = value; }
public void setRoleName(String value) { this.role_name = value; }
public void setRoleDesc(String value) { this.role_desc = value; }
}
但我不断收到此错误:
HTTP Status 500 - An exception occurred processing JSP page /pages/Dashboard.jsp at line 20
type Exception report
message An exception occurred processing JSP page /pages/Dashboard.jsp at line 20
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 /pages/Dashboard.jsp at line 20
17: 18:
Next Meetings
19:
20:
21:
22:
23:Stacktrace: org.apache.jasper.servlet.JspServletWrapper.handleJspException(Unknown Source) org.apache.jasper.servlet.JspServletWrapper.service(Unknown Source) org.apache.jasper.servlet.JspServlet.serviceJspFile(Unknown Source) org.apache.jasper.servlet.JspServlet.service(Unknown Source) javax.servlet.http.HttpServlet.service(Unknown Source) controller.Dashboard.doGet(Dashboard.java:53) javax.servlet.http.HttpServlet.service(Unknown Source) javax.servlet.http.HttpServlet.service(Unknown Source)
root cause
javax.el.PropertyNotFoundException: Property 'role_id' not found on type model.Role javax.el.BeanELResolver$BeanProperties.get(Unknown Source) javax.el.BeanELResolver$BeanProperties.access$300(Unknown Source) javax.el.BeanELResolver.property(Unknown Source) javax.el.BeanELResolver.getValue(Unknown Source) org.apache.jasper.el.JasperELResolver.getValue(Unknown Source) org.apache.el.parser.AstValue.getValue(Unknown Source) org.apache.el.ValueExpressionImpl.getValue(Unknown Source) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(Unknown Source) org.apache.jsp.pages.Dashboard_jsp._jspx_meth_c_005fout_005f0(Dashboard_jsp.java:197) org.apache.jsp.pages.Dashboard_jsp._jspx_meth_c_005fforEach_005f0(Dashboard_jsp.java:161) org.apache.jsp.pages.Dashboard_jsp._jspService(Dashboard_jsp.java:108) org.apache.jasper.runtime.HttpJspBase.service(Unknown Source) javax.servlet.http.HttpServlet.service(Unknown Source) org.apache.jasper.servlet.JspServletWrapper.service(Unknown Source) org.apache.jasper.servlet.JspServlet.serviceJspFile(Unknown Source) org.apache.jasper.servlet.JspServlet.service(Unknown Source) javax.servlet.http.HttpServlet.service(Unknown Source) controller.Dashboard.doGet(Dashboard.java:53) javax.servlet.http.HttpServlet.service(Unknown Source) javax.servlet.http.HttpServlet.service(Unknown Source)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.56-gentoo logs. Apache Tomcat/7.0.56-gentoo
出了什么问题？
最佳答案
您已使用属性role_id
<c:out value="${role.role_id}"></c:out>
但你没有这样的属性(property)。要成为属性 role_id，您需要为名称 role_id 生成 getter 和 setter。
关于javax.el.PropertyNotFoundException : Property 'role_id' not found on type model. 角色，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30014285/