我有一个处理上传Excel文件的代码，通过阅读并将其存储在数据库中。代码如下，它正在编译但是给出了错误。
请参阅以下代码：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
<link href="http://fonts.googleapis.com/css?family=Source+Sans+Pro:200,300,400,600,700,900|Quicksand:400,700|Questrial" rel="stylesheet" />
<link href="css/default.css" rel="stylesheet" type="text/css" media="all" />
<link href="css/fonts.css" rel="stylesheet" type="text/css" media="all" />
<%@ page import="java.sql.*" %>
<%@ page import="com.oreilly.servlet.*" %>
<%@ page import="java.io.*"%>
<%@ page import="java.util.*"%>
<%@ page import="com.oreilly.servlet.*" %>
<%@page import=" org.apache.poi.hssf.usermodel.*"%>
<%@ page import ="org.apache.poi.poifs.filesystem.*" %>
<%@ page import="org.apache.poi.ss.usermodel.Row" %>
<%@ page import ="java.util.Date" %>
<%@ page import ="java.io.*" %>
</head>
<body>
<div id="header-wrapper">
<div id="header" class="container">
<div id="logo">
<h1><span class="icon icon-cog"></span><a href="#">MPSTME Exam Portal</a></h1>
<div id="menu">
<ul>
<li><a href="homepage_teacher.html" accesskey="1" title="">Homepage</a></li>
<li><a href="#" accesskey="2" title="">New Teacher</a></li>
<li><a href="#" accesskey="3" title="">New Student</a></li>
<li class="current_page_item"><a href="admin_timetable.jsp" accesskey="5" title="">Upload Timetable</a></li>
<li><a href="index.html" accesskey="6" title="">Logout</a></li>
</ul>
</div>
</div>
</div>
</div>
<div id="page-wrapper">
<div id="page" class="container">
<div class="title">
<h2>Upload Timetable</h2>
</div>
</div>
</div>
<div class="wrapper">
<div id="three-column" class="container">
<%
MultipartRequest m = new MultipartRequest(request,"/Users/Documents/workspace/exam_portal/WebContent",96163690);
out.print("uploaded");
%>
<%
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/examportal","root","mpstme");
%>
<%
String filename="/Users/hemshah/Documents/workspace/exam_portal/WebContent/timetable.xls";
ArrayList dataHolder = readExcelFile(filename);
String sql = "insert into timetable values(?,?,?,?,?,?)";
ps = conn.prepareStatement(sql);
int count = 0;
ArrayList cellStoreArrayList = null;
System.out.println("dataHolder.size() = " + dataHolder.size());
for (int i = 1; i < dataHolder.size(); i++) {
System.out.println("dataHolder.size()="+dataHolder.get(i));
cellStoreArrayList = (ArrayList)dataHolder.get(i);
ps.setString(1,((HSSFCell)cellStoreArrayList.get(0)).toString());
ps.setString(2,((HSSFCell)cellStoreArrayList.get(1)).toString());
ps.setString(3,((HSSFCell)cellStoreArrayList.get(2)).toString());
ps.setString(4,((HSSFCell)cellStoreArrayList.get(3)).toString());
ps.setString(5,((HSSFCell)cellStoreArrayList.get(4)).toString());
ps.setString(6,((HSSFCell)cellStoreArrayList.get(5)).toString());
count= ps.executeUpdate();
// System.out.print(((HSSFCell)cellStoreArrayList.get(5)).toString() + "\t");
}
%>
<%!
PreparedStatement ps=null;
public static ArrayList readExcelFile(String filename) {
ArrayList cellArrayListHolder=new ArrayList();
ArrayList cellStoreArrayList=new ArrayList();
ArrayList test = null;
try {
FileInputStream myInput = new FileInputStream(filename);
POIFSFileSystem myFileSystem = new POIFSFileSystem(myInput);
HSSFWorkbook myWorkbook = new HSSFWorkbook(myFileSystem);
HSSFSheet mySheet = myWorkbook.getSheetAt(0);
Iterator rowIter = mySheet.rowIterator();
while (rowIter.hasNext()) {
HSSFRow myrow = (HSSFRow) rowIter.next();
Iterator cellIter = myrow.cellIterator();
//ArrayList cellStoreArrayList = new ArrayList();
while(cellIter.hasNext()) {
HSSFCell myCell = (HSSFCell) cellIter.next();
cellStoreArrayList.add(myCell);
}
}
} catch(Exception e) { }
return cellStoreArrayList;
}
%>
<% if(count>0) { %>
Following details from Excel file have been inserted in student table of database
<table>
<tr>
<th>Subject ID</th>
<th>Subject Name</th>
<th>Faculty</th>
<th>Date</th>
<th>Time</th>
<th>Class</th>
</tr>
<% for (int i = 1; i < dataHolder.size(); i++) {
cellStoreArrayList = (ArrayList) dataHolder.get(i); %>
<tr>
<td><%=((HSSFCell)cellStoreArrayList.get(0)).toString() %></td>
<td><%=((HSSFCell)cellStoreArrayList.get(1)).toString() %></td>
<td><%=((HSSFCell)cellStoreArrayList.get(2)).toString() %></td>
<td><%=((HSSFCell)cellStoreArrayList.get(3)).toString() %></td>
<td><%=((HSSFCell)cellStoreArrayList.get(4)).toString() %></td>
<td><%=((HSSFCell)cellStoreArrayList.get(5)).toString() %></td>
</tr>
<%} }%>
</table>
</div>
</body>
</html>
以下是错误的堆栈跟踪：
org.apache.jasper.JasperException: An exception occurred processing JSP page /admin_timetable_upload.jsp at line 80
77: for (int i=1;i < dataHolder.size(); i++)
78: {
79: System.out.println("dataHolder.size()="+dataHolder.get(i));
80: cellStoreArrayList=(ArrayList)dataHolder.get(i);
81: ps.setString(1,((HSSFCell)cellStoreArrayList.get(0)).toString());
82: ps.setString(2,((HSSFCell)cellStoreArrayList.get(1)).toString());
83: ps.setString(3,((HSSFCell)cellStoreArrayList.get(2)).toString());
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:575)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
root cause
java.lang.ClassCastException: org.apache.poi.hssf.usermodel.HSSFCell cannot be cast to java.util.ArrayList
org.apache.jsp.admin_005ftimetable_005fupload_jsp._jspService(admin_005ftimetable_005fupload_jsp.java:199)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:439)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
我该如何解决这个问题？
答案 0 :(得分：2)
你不需要这样做：
cellStoreArrayList = (ArrayList) dataHolder.get(i);
进入ArrayList，它已经返回一个HSSFCell，所以你只需要这样做：
HSSFCell cell = dataHolder.get(i);