【发布时间】：2012-06-08 07:26:50
【问题描述】：
我有一个 index.jsp 页面，其中包含名为“刷新”、“转发”和“编辑”的按钮。如果我单击刷新按钮，那么它会调用一个 Servlet，并且值会显示在 index.jsp 页面上。
当我单击“转发”按钮时，它会调用另一个 servlet 并转到另一个页面 forward_call_log.jsp。在此页面中，当我单击“转发”按钮时，它会调用另一个 servlet，并且该 servlet 会显示 index.jsp 页面。显示 index.jsp 页面，但数据库中的值不可用。
我该如何解决这个问题？
index.jsp
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Pager Example - www.javaworkspace.com</title>
</head>
<body>
<form method="post" action="./Problem_retrive" >
<input type="submit" value="Refresh">
</form>
<form action="./edit_call_log" method="post">
<%
ResultSet rs=null;
try
{
rs=(ResultSet)request.getAttribute("rs");
//request.setAttribute("rs",rs);
if(rs.next())
{
%>
<table border=1 cellspacing=1 cellpadding=1>
<tr>
<th>check box</th>
<th>Problem ID</th>
<th>user ID</th>
</tr>
<%
do
{
%>
<tr>
<td><input type="checkbox" name="checkbox" value="<%=rs.getString(1) %>"></td>
<td><%=rs.getString(1) %></td>
<td><%=rs.getString(2) %></td>
</tr>
<%
}
while(rs.next());
%>
</table>
<%
}
else
{
out.println("hiiiiiiii");
}
}
catch(Exception e)
{
e.printStackTrace();
}
%>
<input type="submit" name="act" value="EditCall"/>
<input type="submit" name="act" value="Forward"/>
</form>
</body>
</html>
点击Refresh按钮后调用Edit_call_servlet.java
import database.problemdesc.Problem_retrive_class;
import database.user_master.User_master;
import java.sql.*;
public class Edit_call extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
response.setContentType("text/html");
HttpSession session = request.getSession(true);
ResultSet rs=null;
Problem_retrive_class prc=new Problem_retrive_class();
int checkbox=Integer.parseInt(request.getParameter("checkbox"));
session.setAttribute("problem_id", checkbox);
String act=request.getParameter("act");
if(act.equals("EditCall"))
{
try
{
rs=prc.select_table(checkbox);
RequestDispatcher rd = request.getRequestDispatcher("edit_call_log.jsp");
request.setAttribute("rs", rs);
rd.forward(request, response);
}
catch(Exception e)
{
e.printStackTrace();
}
}
else if(act.equals("Forward"))
{
System.out.println("Forward page");
try
{
ResultSet rs1=null;
User_master um=new User_master();
rs=prc.select_table(checkbox);
if(rs.next())
{
System.out.println("Value retrieve from PRC select_table");
rs1=um.select_table(rs.getString(7));
System.out.println("Value retrieve from PRC select_table"+rs.getString(7));
RequestDispatcher rd = request.getRequestDispatcher("forward_call_log.jsp");
request.setAttribute("rs1", rs1);
request.setAttribute("user_type", rs.getString(7));
rd.forward(request, response);
}
else
{
RequestDispatcher rd = request.getRequestDispatcher("index.jsp");
rd.forward(request, response);
}
}
catch(Exception e)
{
}
}
}
}
点击Forward按钮后调用Problem_retrive_servlet.java
import database.problemdesc.Problem_retrive_class;
public class Problem_retrive extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
response.setContentType("text/html");
PrintWriter out=response.getWriter();
Connection con=null;
ResultSet rs=null;
try
{
Problem_retrive_class prc=new Problem_retrive_class();
DBBean db=new DBBean();
con=db.getDBConnection();
rs=prc.select_table();
RequestDispatcher rd = request.getRequestDispatcher("index.jsp");
rd.forward(request, response);
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
【问题讨论】：
-
您描述的问题是
forward_call_log.jsp上的一个名为Forward 的按钮，但是您没有包含此代码。请定义单击该按钮时将触发哪个类和方法？