一句话笑话大全爆笑:看看这个jsp的bean错误

来源:百度文库 编辑:中科新闻网 时间:2024/03/29 21:56:18
下面是jsp代码:
<%@ page contentType="text/html;charset=gb2312" %>
<%@ page language="java" %>
<html>
<head><title> </title>
<body>
<jsp:useBean id="goodsbean" scope="application" class="sale.goods" />
<%
goodsbean.setProduct("clock");
goodsbean.setPrice("$383838");
%>
usemethod 1:<br>
<%=goodsbean.getProduct() %><br>
<%=goodsbean.getPrice() %><br>
usemethod 2:<br>

<jsp:getProperty name="goodsbean" property="product" /><br>
<jsp:getProperty name="goodsbean" property="price" /><br>

<hr>
<!--<jsp:setProperty name="beanname" property="bean's_menmber " param="value" /> 设置对象的值-->
</body>
</html>
下面是bean代码:
package sale;

public class goods{
String product;
String price;
public goods(){
product="apple";
price="$30";
}
public void setProduct(String pro){
product=pro;
}
public void setPrice(String pri){
price=pri;
}
public String getProduct(){
return(this.product);
}
public String getPrice(){
return(this.price);
}
}
,我把编译好的bean放在了web-info文件夹中的class中的sale里面了,但是执行的时候有错误。可以告诉我为什么?
按照王凯问 我改好了
但是还是有错误入下:
java.lang.NullPointerException
org.apache.jasper.runtime.JspRuntimeLibrary.internalIntrospecthelper(JspRuntimeLibrary.java:320)
org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(JspRuntimeLibrary.java:306)
org.apache.jsp.xf.usebean_jsp._jspService(usebean_jsp.java:77)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

兄弟~去掉
<!--<jsp:setProperty name="beanname" property="bean's_menmber " param="value" /> 设置对象的值-->
这句注释你就能看到结果了~

还有 <jsp:useBean id="goodsbean" scope="application" class="sale.goods" />
此用法和<jsp:useBean id="goodsbean" scope="application" class="sale.goods"> </jsp:useBean>
此用法没有任何区别~

<jsp:useBean id="goodsbean" scope="application" class="sale.goods" />

把上面的改成

<jsp:useBean id="goodsbean" scope="application" class="sale.goods"> </jsp:useBean>