jsp错误提示
jsp代码
HTML code
<html>
<head>
<title>using jsp:setProperty</title>
</head>
<body>
<table border="1" align="center">
    <tr><th class="title">
        using jsp:setProperty
</table>
<jsp:useBean id="entry" class="bean.SaleEntry"></jsp:useBean>
<jsp:setProperty property="itemID" name="entry" value='<%=request.getParameter("itemID") %>'/>
<jsp:setProperty property="numItems" name="entry" value='<%=request.getParameter("numItems") %>'/>
<jsp:setProperty property="discountcode" name="entry" value='<%=request.getParameter("discountcode") %>'/>
<br/>
<table border="1" align="center">
    <tr class="colored"><th>Item ID</th><th>unit price</th><th>number ordered</th><th>total price</th></tr>
    <tr align="right">
        <td><jsp:getProperty name="entry" property="itemID" /></td>
        <td><jsp:getProperty name="entry" property="itemCost"/></td>
        <td><jsp:getProperty property="numItems" name="entry"/> </td>
        <td><jsp:getProperty property="totalCost" name="entry"/></td>
    </tr>
</table>
</body>
</html>
----------------
bean.SaleEntry的代码:
package bean;
public class SaleEntry {
	private String itemID = "unknown";
	private double discountcode = 1.0;
	private int numItems = 0;	
	public String getItemID() {
		return itemID;
	}
	public void setItemID(String itemID) {
		this.itemID = itemID;
	}
	public double getDiscountcode() {
		return discountcode;
	}
	public void setDiscountcode(double discountcode) {
		this.discountcode = discountcode;
	}
	public int getNumItems() {
		return numItems;
	}
	public void setNumItems(int numItem) {
		this.numItems = numItem;
	}
	public double getItemCost(){
		double cost = 0.0;
		if (itemID.equals("a1234"))
			cost = 12.99*getDiscountcode();
		else
			cost = -9999;
		return (roundToPennies(cost));
	}
	private double roundToPennies(double cost) {		
		return (Math.floor(cost*100)/100.0);
	}	
	public double getTotalCost(){
		return(getItemCost()*getNumItems());
	}
}
---------------------
错误提示:
HTTP Status 500 -  
--------------------------------------------
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 /SaleEntry.jsp at line 12
9: </table>
10: <jsp:useBean id="entry" class="bean.SaleEntry"></jsp:useBean>
11: <jsp:setProperty property="itemID" name="entry" value='<%=request.getParameter("itemID") %>'/>
12: <jsp:setProperty property="numItems" name="entry" value='<%=request.getParameter("numItems") %>'/>
13: <jsp:setProperty property="discountcode" name="entry" value='<%=requ