Question

以下是我在jsp文件中的代码：

int s_id = session.getAttribute("s_id") != null ? ((Integer)     session.getAttribute("s_id")).intValue() : 0 ;
String Pending = "Pending";
%>
<!-- <jsp:useBean id="link" scope="application" class = "Shop" /> -->
<%
Shop s = new Shop();
int g_orderQuantity=0;

错误：

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: Unable to compile class for JSP: 

An error occurred at line: 30 in the jsp file: /ShopViewOrder.jsp
Shop cannot be resolved to a type
line 30 : <!-- <jsp:useBean id="link" scope="application" class = "Shop" /> -->

An error occurred at line: 32 in the jsp file: /ShopViewOrder.jsp
Shop cannot be resolved to a type
line 32 : Shop s = new Shop();

一些答案如页："Import cannot be resolved" with JSP 建议使用页面导入指令如下： <%@ page import="pkgname.Class1"%> 他们坐在那里你必须给出一个完全合格的班级名称。

我按照以下方式放置了我的Shop类：C：\ Users \ Documents \ ShopSystem-AWSJavaWebProject \ src \ myPackage \ Shop.java 现在我尝试使用以下语法： <%@ page import="myPackage.Shop"%> 但这也不起作用......它给出了一个错误，说导入myPackage无法解决！

然后按照Eclipse is not importing classes in jsp files中提到的解决方案我确保已启用偏好设置＆gt; import-＆gt; Web-＆gt; Jsp文件 - >编辑器 - >内容辅助 - > Add_import_instead_of_qualified_name 现在，当我使用上述行时：<%@ page import="myPackage.Shop"%> 我现在收到以下错误：

exception : org.apache.jasper.JasperException: Unable to compile class for JSP: 

An error occurred at line: 16 in the generated java file
Only a type can be imported. myPackage.Shop resolves to a package

An error occurred at line: 31 in the jsp file: /ShopViewOrder.jsp
Shop cannot be resolved to a type
line 31: <!-- <jsp:useBean id="link" scope="application" class = "Shop" /> -->

An error occurred at line: 33 in the jsp file: /ShopViewOrder.jsp
Shop cannot be resolved to a type
line 33 : Shop s = new Shop();

另一页：problem in importing java class in jsp 建议<%@ page language="java" import="yourpackage.subpackage.*,java.util.*" %> 因此我将我的代码更新为：

<%@ page language="java" import="myPackage.Shop" %>

但错误仍然保持不变！

我甚至尝试了以下内容：

<%@ page language="java" import="myPackage.Shop" session="true"%>

根据To import class to JSP in Tomcat6的建议但错误定义没有变化！

在另一个网站上，它表示要创建要加载的类的公共构造函数。我不知道这有多大帮助，我甚至尝试过那也行不通！

请帮忙......

正如我要求添加整个代码的片段：

int s_id = session.getAttribute("s_id") != null ? ((Integer) session.getAttribute("s_id")).intValue() : 0 ;
String Pending = "Pending";
<jsp:useBean id="link" scope="application" class = "myPackage.Shop" />
myPackage.Shop s = new myPackage.Shop();
int g_orderQuantity=0;
Statement stmt6 = con.createStatement();
// a shop can select values from Order table
ResultSet rs3 = stmt6.executeQuery("SELECT * FROM ShopSystem.Order where s_id="+s_id+"     AND  status='"+Pending+"'");
//code to declare some Vectors
while(rs3.next())
{   
    status1.add((i),rs3.getString("status"));
    status=status1.elementAt(i);        
    // in the above way am adding ResultSet values to the vector and then copying it to string.
    //i maintains the total count of all my orders
    i++;
}
for(int j=0; j<i; j++)
{
     //checking if the order table is empty
    if((g_quantityRequired == 0)||(Cust_address.equals(null))||(email.equals(null))||((contact.equals(null)))||(total_amount == 0))
    {           %>          <br> There are no pending orders. <br>           
        <%
        %>          <form name="Back" method="post" action="ShopMenu3.jsp">
        <input type="submit" value="Back">
        </form><br><br>         <%
                }        
    // Now that the order table is not empty continue to process the order..
    int g_available=0;
    //check availability of g_id in s_id
    boolean b_availability = s.checkAvailability_perShop(s_id, g_id, g_quantityRequired);
            //if sufficient quantity is not available then place an order
    if(b_availability == false)
    {           // example, if required=50, then order is placed for 100 items
        // but if required is 150, then order is placed for 150 items
        g_orderQuantity = (100>g_quantityRequired)?100 : (g_quantityRequired+100);          
        //placing order and updating the Grocery_perShop table return the amount available of g_id in s_id
        g_available = s.placeOrder_perShop(s_id, g_id, g_orderQuantity);
    }        %> 
        New g_avaliable = <%= g_available %>. The value has been updated in the database.
    <%        //now that sufficient g_id is available with s_id, we execute the order
    //updating the Grocery_perShop table
    g_available = g_available - g_quantityRequired;
    //code to insert updated values in table

sc.close();
%>    <form name="Back" method="post" action="ShopMenu3.jsp">
<input type="submit" value="Back">
</form><br><br>

Answer 1

如果您尝试访问的类位于应用程序的mypackage下，那么您将拥有jsp文件，以下语句应该可用，

<jsp:useBean id="link" scope="application" class = "mypackage.Shop" />

在完成构建后检查是否有文件。在使用eclipse时检查build-＆gt;类。

Answer 2

您必须在<jsp:useBean>中为班级使用完全限定名称。 import

未考虑<jsp:useBean>页面指令

<jsp:useBean id="link" scope="application" class = "mypackage.Shop" />

直接来自官方Oracle Documentation - Creating and Using a JavaBeans Component

为class属性提供的值必须是fully qualified class name。

请注意，bean不能位于未命名的包中。因此，值的格式必须为package-name.class-name。

HTTP状态500 - 无法为JSP编译类：无法将import解析为类型

2 个答案: