1.确定tomcat lib文件夹下有mysql链接文件
2.写入context.xml文件 位置如图
<Context>
<Resource name="jdbc/registration"
auth="Container" type="javax.sql.DataSource"
maxActive="100" maxIdle="30" maxWait="10000"
username="root" password="123456"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/java_web?useUnicode=true&characterEncoding=utf-8"/>
</Context>
3.配置web.xml文件 位置如图
<resource-ref>
<res-ref-name>jdbc/registration</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
图中标注请保持一致
4.新建test.jsp文件测试
假设有如下数据库和表
新建test.jsp
内容如下：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.sql.*" %>
<%@ page import="javax.sql.*" %>
<%@ page import="javax.naming.*" %>
<!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">
<title>test</title>
</head>
<body>
<%
request.setCharacterEncoding("utf-8");
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
Context initContext = new InitialContext();
DataSource ds = (DataSource)initContext.lookup("java:/comp/env/jdbc/registration");
conn = ds.getConnection();
pstmt = conn.prepareStatement("select * from card_user");
// pstmt.setString(1, username);
//execute: boolean
//executeQuery: ResultSet
//executeUpdate: int
rs = pstmt.executeQuery();
while(rs.next()) {
String name = rs.getString("username");
String pwd = rs.getString("password");
out.println(name);
out.println(pwd);
}
}catch (Exception e) {
e.printStackTrace();
} finally {
if(rs!=null){
rs.close();
}
if(pstmt!=null){
pstmt.close();
}
if(conn!=null){
conn.close();
}
//rs
//pstmt
//conn
}
%>
</body>
</html>
运行效果
在tomcat运行
