没有数据引出.为什么? [英] No data extrated. why?
问题描述
Java& SQL专家，当我运行此jsp页面时，我没有收到提取到表中的任何数据吗?可能是什么原因 ?我收到一种带有四列表的空白页，如下所示.没有从数据库中检索数据，为什么?
我想知道问题是否来自下面的行代码中双冒号的间距.当我消除双冒号之间的空格时，我收到一条错误消息.
Java & SQL experts, when I run this jsp page I don't receive any data extracted into the table? What could be the reason ? I receive sort of a blank page with a four column table as highlighted below. No data is being retrieved from the database, why ?
I'm wondering whether the problem comes from the spacing in the double colons in the line codes below. When I eliminate the space in between the double colons I receive an error message.
<sql : query dataSource="${snapshot}" var="result">
SELECT * from Employees;
</sql : query>
SELECT * from Employees;
Emp ID年龄名字姓氏
SELECT * from Employees;
Emp ID Age First Name Last Name
这是程序:
<%@ page import="java.io.*, java.util.*, java.sql.*" %>
<%@ page import="javax.servlet.http.*, javax.servlet.*" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql" %>
<html>
<head>
<title>SELECT operation</title>
</head>
<body>
<sql : setDataSource var="snapshot" driver="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost/EMP"
user="root" password="password"/>
<sql : query dataSource="${snapshot}" var="result">
SELECT * from Employees;
</sql : query>
<table border="1" width="100%">
<tr>
<th>Emp ID</th>
<th>Age</th>
<th>First Name</th>
<th>Last Name</th>
</tr>
<c:forEach var="row" items="${result.rows}">
<tr>
<td><c:out value="${row.id}"/></td>
<td><c:out value="${row.age}"/></td>
<td><c:out value="${row.first}"/></td>
<td><c:out value="${row.last}"/></td>
</tr>
</c:forEach>
</table>
</body>
</html>
推荐答案
<%@ page import="java.io.*, java.util.*, java.sql.*" %>
<%@ page import="javax.servlet.http.*, javax.servlet.*" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql" %>
<html>
<head>
<title>SELECT operation</title>
</head>
<body>
<sql : setDataSource var="snapshot" driver="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost/EMP"
user="root" password="password"/>
<sql : query dataSource="${snapshot}" var="result">
SELECT id,age,first,last from Employees;
</sql : query>
<table border="1" width="100%">
<tr>
<th>Emp ID</th>
<th>Age</th>
<th>First Name</th>
<th>Last Name</th>
</tr>
<c:forEach var="row" items="${result.rows}">
<tr>
<td><c:out value="${row.id}"/></td>
<td><c:out value="${row.age}"/></td>
<td><c:out value="${row.first}"/></td>
<td><c:out value="${row.last}"/></td>
</tr>
</c:forEach>
</table>
</body>
</html>
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