JavaEE连接数据库练习
登录端
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!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>Insert title here</title> </head> <body> <form action="Check2.jsp" method="post"> 卡号:<input type="text" name="cardid1"><br> 密码:<input type="password" name="password1"><br> <input type="submit" value="登录"> </form>> </body> </html>
连接请求端
<%@page import="com.web.cardDAO"%> <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!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>Insert title here</title> </head> <body> <% String cardid=request.getParameter("cardid1"); String password=request.getParameter("password1"); if(cardid==null||password==null||cardid.equals("") || password.equals("")) { out.write("请正确登录系统"); } else { //检查登录信息 cardDAO cd=new cardDAO(); if(cd.checklogin(cardid, password)) { out.write("登录成功"); } else { out.write("登录失败"); } } %> </body> </html>
Java代码类
package com.web; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import com.mchange.v2.c3p0.ComboPooledDataSource; public class cardDAO { ComboPooledDataSource cpd=new ComboPooledDataSource("helloc3p0"); public boolean checklogin(String cardid,String password) { boolean boo=false; try { Connection conn=cpd.getConnection(); PreparedStatement ps=conn.prepareStatement( "select * from bank where ba_card=? and ba_password=?"); ps.setString(1, cardid); ps.setString(2, password); ResultSet rs=ps.executeQuery(); boo=rs.next(); rs.close(); ps.close(); conn.close(); cpd.close(); } catch (SQLException e) { // TODO 自动生成的 catch 块 e.printStackTrace(); } return boo; } }