先来回顾一下JDBC的六个步骤：
1.加载驱动
String DRIVER = "oracle.jdbc.OracleDriver"; Class.forName(DRIVER );
2.建立和数据库的连接
String URL = "jdbc:oracle:thin:@127.0.0.1:1521:XE"; String USER = "SCOTT"; String PASSWORD = "TIGER"; Connection connection = DriverManager.getConnection(URL, USER, PASSWORD);
3.创建语句对象
String sql = "SELECT * FROM emp"; PreparedStatement pstm = connection.prepareStatement(sql);
4.执行SQL语句
ResultSet rs = pstm.executeQuery();
5.处理结果
6.释放资源
以Oracle中自带的emp表为例，展示如何用JDBC查询并展示数据：
<%@page import="java.sql.*"%>
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<%@ page import="io.zhangjia.test.Book"%>
<%@ page import="java.util.*"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style type="text/css">
table {
width: 40%;
border: 1px #000 solid;
border-spacing: 0; /*设置相邻单元格的边框间的距离为0*/
border-collapse: collapse; /*合并边框*/
}
td, th {
border: 1px #000 solid;
}
</style>
<title>Insert title here</title>
</head>
<body>
<%
String DRIVER = "oracle.jdbc.OracleDriver";
String URL = "jdbc:oracle:thin:@127.0.0.1:1521:XE";
String USER = "SCOTT";
String PASSWORD = "TIGER";
Class.forName(DRIVER);
Connection connection = DriverManager.getConnection(URL, USER, PASSWORD);
String sql = "SELECT * FROM emp";
PreparedStatement pstm = connection.prepareStatement(sql);
ResultSet rs = pstm.executeQuery();
%>
<table>
<tr>
<th>EMPNO</th>
<th>ENAME</th>
<th>JOB</th>
<th>MGR</th>
<th>HIREdATE</th>
<th>SAL</th>
<th>COMM</th>
<th>DEPTNO</th>
</tr>
<%
while(rs.next()) {
%>
<tr>
<!-- 注意下标不是从0开始，而是从1开始 -->
<td><%= rs.getObject(1) %></td>
<td><%= rs.getObject(2) %></td>
<td><%= rs.getObject(3) %></td>
<td><%= rs.getObject(4) %></td>
<td><%= rs.getObject(5) %></td>
<td><%= rs.getObject(6) %></td>
<td><%= rs.getObject(7) %></td>
<td><%= rs.getObject(8) %></td>
</tr>
<%
}
%>
</table>
<%
rs.close();
pstm.close();
connection.close();
%>
</body>
</html>
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