《Java Web开发实战经典》李兴华王月清第5章 JSP基础语法 5.4.4 数据库连接操作例5.16

本文链接： https://blog.csdn.net/weixin_41899098/article/details/98224670

例5.16 使用JSP列出emp表数据–list_emp.jsp

<%@ page contentType="text/html" pageEncoding="GBK"%>
<%@ page import="java.sql.*"%>
<html>
<head><title>www.mldnjava.cn，MLDN高端Java培训</title></head>
<body>
<%!
	public static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ;
	public static final String DBURL = "jdbc:mysql://localhost:3306/mldn" ;
	public static final String DBUSER = "root" ;
	public static final String DBPASS = "mysqladmin" ;
%>
<%
	Connection conn = null ;
	PreparedStatement pstmt = null ;
	ResultSet rs = null ;
%>
<%
try{
	Class.forName(DBDRIVER) ;
	conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS) ;
	String sql = "SELECT empno,ename,job,sal,hiredate FROM emp" ;
	pstmt = conn.prepareStatement(sql) ;
	rs = pstmt.executeQuery() ;
%>
<center>
<table border="1" width="80%">
	<tr>
		<td>雇员编号</td>
		<td>雇员姓名</td>
		<td>雇员工作</td>
		<td>雇员工资</td>
		<td>雇佣日期</td>
	</tr>
<%
	while(rs.next()){
		int empno = rs.getInt(1) ;
		String ename = rs.getString(2) ;
		String job = rs.getString(3) ;
		float sal = rs.getFloat(4) ;
		java.util.Date date = rs.getDate(5) ;
%>
	<tr>
		<td><%=empno%></td>
		<td><%=ename%></td>
		<td><%=job%></td>
		<td><%=sal%></td>
		<td><%=date%></td>
	</tr>	
<%
	}
%>
</table>
</center>
<%
}catch(Exception e)	{
	System.out.println(e) ;
}finally{
	rs.close() ;
	pstmt.close() ;
	conn.close() ;	// 如果直接关闭连接也可以
}
%>
</body>
</html>

2019/8/2我在运行此代码时，Class.forName(DBDRIVER) ;conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS) ;语句错误，连接不上数据库，原因是用的JDBC版本不一样（我用的是8.0.16版本，作者用的要老很多），将DBDRIVER和DBURL修改一下就可以：

<%@ page contentType="text/html" pageEncoding="GBK"%>
<%@ page import="java.sql.*"%>
<html>
<head><title>www.mldnjava.cn</title></head>
<body>
<%!
	public static final String DBDRIVER = "com.mysql.cj.jdbc.Driver";
	public static final String DBURL = "jdbc:mysql://localhost:3306/mldn?useSSL=true&characterEncoding=GBK&serverTimezone=GMT";
	public static final String DBUSER = "williamdsy";
	public static final String DBPASS = "DSY.jxnu.1998";
%>
<%
	Connection conn = null;
	PreparedStatement pstmt = null;
	ResultSet rs = null;
%>
<%
	try
	{
		Class.forName(DBDRIVER);
		conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS);
		String sql = "select empno,ename,job,sal,hiredate from emp";
		pstmt = conn.prepareStatement(sql);
		rs = pstmt.executeQuery();
%>
<center>
<table border="1" width="80%">
	<tr>
		<td>雇员编号</td>
		<td>雇员姓名</td>
		<td>雇员工作</td>
		<td>雇员工资</td>
		<td>雇佣日期</td>
	</tr>
<%
	while(rs.next())
	{
		int empno = rs.getInt(1);
		String ename = rs.getString(2);
		String job = rs.getString(3);
		float sal = rs.getFloat(4);
		java.util.Date date = rs.getDate(5);
%>
	<tr>
		<td><%=empno%></td>
		<td><%=ename%></td>
		<td><%=job%></td>
		<td><%=sal%></td>
		<td><%=date%></td>
	</tr>
<%
	}
%>
	</table>
</center>
<%
	}
	catch(Exception e)
	{
		System.out.println(e);
	}
	finally
	{
		rs.close();
		pstmt.close();
		conn.close();
	}
%>
</body>
</html>

《Java Web开发实战经典》李兴华 王月清 第5章 JSP基础语法 5.4.4 数据库连接操作 例5.16

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《Java Web开发实战经典》李兴华王月清第5章 JSP基础语法 5.4.4 数据库连接操作例5.16