我正在尝试根据用户输入从数据库中获取数据，以便用户可以跟踪订单。该文件在IDE中编译良好，但在浏览器中抛出此错误：
javax.servlet.ServletException：java.sql.SQLException：ResultSet关闭后不允许操作
form.jsp
<form action="viewOrderHistory" method="Post" id="invoiceNumberLookup">
Invoice Number:
<BR><BR>
<INPUT TYPE="TEXT" NAME="invoice_number">
<INPUT TYPE="SUBMIT" value="View Order">
</form>
<form action="viewOrderHistory" method="Post" id="referenceNumberLookup">
Reference Number:
<BR><BR>
<INPUT TYPE="TEXT" NAME="reference_number">
<INPUT TYPE="SUBMIT" value="View Order">
</form>
result.jsp中
<%@ page import="java.sql.*" %>
<HTML>
<HEAD>
<TITLE>Fetching Data From a Database</TITLE>
</HEAD>
<BODY>
<H1>Fetching Data From a Database</H1>
<%
Connection connection = DriverManager.getConnection(
"jdbc:mysql://localhost/app?user=root&password=password");
Statement statement = connection.createStatement();
String first_name = request.getParameter("first_name");
String last_name= request.getParameter("last_name");
String invoice_number = request.getParameter("invoice_number");
String reference_number = request.getParameter("reference_number");
String amount = request.getParameter("amount");
String status= request.getParameter("status");
String date_created = request.getParameter("date_created");
String quantity = request.getParameter("quantity");
String product_name = request.getParameter("product_name");
String product_price = request.getParameter("product_price");
ResultSet resultset =
statement.executeQuery("select * from customer where first_name = '" + first_name + "'") ;
statement.executeQuery("select * from customer where last_name = '" + last_name + "'") ;
statement.executeQuery("select * from customer_order where amount = '" + amount + "'") ;
statement.executeQuery("select * from customer_order where date_created = '" + date_created + "'") ;
statement.executeQuery("select * from customer_order where reference_number = '" + reference_number + "'") ;
statement.executeQuery("select * from customer_order where invoice_number = '" + invoice_number + "'") ;
statement.executeQuery("select * from customer_order where status = '" + status + "'") ;
statement.executeQuery("select * from ordered_product where quantity = '" + quantity + "'") ;
statement.executeQuery("select * from ordered_product where product_name = '" + product_name + "'") ;
statement.executeQuery("select * from ordered_product where product_price = '" + product_price + "'") ;
if(!resultset.next()) {
out.println("Sorry, could not find that order. ");
} else {
%>
<div class="banner">
<%
}
%>
</div>
Invoice Number: <%= resultset.getString("invoice_number") %>
Reference Number: <%= resultset.getString("reference_number") %>
Created by: <%= resultset.getString("first_name") %> <%= resultset.getString("last_name") %>
Date Created: <%= resultset.getString("date_created") %>
Grand Total: <%= resultset.getString("amount") %>
Order:
<TABLE BORDER="1">
<TR>
<TH>Product Name</TH>
<TH>Product Price</TH>
<TH>Quantity</TH>
</TR>
<TR>
<TD> <%= resultset.getString("product_name") %> </TD>
<TD> <%= resultset.getString("product_price") %> </TD>
<TD> <%= resultset.getString("quantity") %> </TD>
</TR>
</TABLE>
</BODY>
</HTML>
答案 0 :(得分：0)
部分之后
if(!resultset.next()) {
out.println("Sorry, could not find that order. ");
} else {
%>
<div class="banner">
<%
}
你离开了ResultSet。最后的} 放错了地方。关闭桌子后需要去。
修改
也许不是最好的方式，但它会起作用。为每个语句和查询引入更多ResultSet。然后在需要的地方使用它们。
示例：
Statement s1 = connection.createStatement();
Statement s2 = connection.createStatement();
Statement s3 = connection.createStatement();
Statement s4 = connection.createStatement();
...
ResultSet rs1 = s1.exequteQuery(.....);
ResultSet rs2 = s2.exequteQuery(.....);
ResultSet rs3 = s3.exequteQuery(.....);
.......
然后在需要它们的地方使用rs1 .... rsN。工作解决方案：）
答案 1 :(得分：0)
默认情况下，每个Statement对象只能同时打开一个ResultSet对象。
现在，您的程序中包含以下语句：
ResultSet resultset =
statement.executeQuery("select * from customer where first_name = '" + first_name + "'") ;
statement.executeQuery("select * from customer where last_name = '" + last_name + "'") ;
statement.executeQuery("select * from customer_order where amount = '" + amount + "'") ;
statement.executeQuery("select * from customer_order where date_created = '" + date_created + "'") ;
statement.executeQuery("select * from customer_order where reference_number = '" + reference_number + "'") ;
statement.executeQuery("select * from customer_order where invoice_number = '" + invoice_number + "'") ;
statement.executeQuery("select * from customer_order where status = '" + status + "'") ;
statement.executeQuery("select * from ordered_product where quantity = '" + quantity + "'") ;
statement.executeQuery("select * from ordered_product where product_name = '" + product_name + "'") ;
statement.executeQuery("select * from ordered_product where product_price = '" + product_price + "'") ;
这意味着您使用相同的executeQuery对象多次调用Statement。但您只是将第一次执行的结果保存到resultset。
也就是说，ResultSet引用的resultset对象是此声明中的对象：
statement.executeQuery("select * from customer where first_name = '" + first_name + "'") ;
跟随它的所有其他查询都是单独的查询，如果您认为自己在做什么，则不会存储在同一个变量中。他们只是创建ResultSet对象，然后它被抛弃，因为你没有将结果分配给任何变量。
只要您调用第二个executeQuery，因为只允许一个ResultSet对象，ResultSet中存储的resultset对象将被关闭，而新的resultset.next()对象将被关闭打开。然后是另一个，然后是另一个。
无论如何，在您完成所有这些陈述后，您将进入检查ResultSet的部分。但在这一点上，正如我所说，那个对象已经被关闭了。
基本上，您应该决定要运行哪些查询，仅运行该特定查询，然后您在{{{{}}中有一个实时，开放的resultset 1}}。然后你可以填写它。
此外，从结果集中打印值的部分应位于else块内。您将它们放在else的大括号之后，这意味着当查询中没有返回任何行时您会遇到麻烦，因为您无论如何都要尝试打印它们。
答案 2 :(得分：0)
以下代码有效（暗示您使用的是servlet）：
Form.jsp
<form method="post" action="viewPublishers">
Please enter the publisher ID you wish to view:
<BR><br>
<input type='text' name='pub_id' required>
<BR><BR>
<input type='submit' value="View">
</form>
的response.jsp
<%
Connection connection = DriverManager.getConnection("jdbc:mysql://localhost/app?user=root&password=12345");
Statement statement = connection.createStatement();
String pub_id = request.getParameter("pub_id);
ResultSet resultset =
statement.executeQuery("select * from publishers where id = '" + pub_id+ "'") ;
if(!resultset.next()) {
out.println("Sorry, could not find that publisher.Please enter a valid ID. <a href='viewPublishers'>Try Again.</a> ");
} else {
%>
<table>
<thead>
<tr>
<th>Publisher ID</th>
<th>First Name</th>
<th>Last Name</th>
<th>Books</th>
</thead>
<tbody style="font-size:small;">
<tr>
<td data-label="Publiser ID"><%= resultset.getString("pub_id") %></td>
<td data-label="First Name"><%= resultset.getString("first_name") %></td>
<td data-label="Last Name"><%= resultset.getString("last_name") %></td>
<td data-label="Books"><%= resultset.getString("books") %>
</tr>
</tbody>
</table>
<div> <%
}
%></div>