用Java web开发出登录小程序:
login_check.jsp--
<%@ page language="java" contentType="text/html" pageEncoding="GBK"%> <%@ page import = "java.sql.*;"%> <html> <head><title>www.baidu.com,这是一个学习的好网站</title></head> <body> <center> <h1>登录操作</h1> <hr> <%! //定义若干个数据库的连接常量 public static final String DBDRIVER= "org.gjt.mm.mysql.Driver"; public static final String DBURL= "jdbc:mysql://localhost:3306/abc"; public static final String DBUSER= "root"; public static final String DBPASS= "123456"; %> <% Connection conn = null; //数据库连接 PreparedStatement pstmt = null; //数据库预处理 ResultSet rs = null; //查询要处理结果集 boolean flag = false; //保存标记 String name= null; //保存真实姓名 %> <% try { %> <% Class.forName(DBDRIVER); conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS); String sql = "SELECT name FROM user WHERE userid = ? AND password = ?"; pstmt = conn.prepareStatement(sql); pstmt.setString(1,request.getParameter("id")); pstmt.setString(2,request.getParameter("password")); rs = pstmt.executeQuery(); // 查询 if(rs.next()){ //如果有数据表示可以执行 flag =true; name= rs.getString(1); } %> <% }catch(Exception e){ e.printStackTrace(); } finally{ //关闭数据源 try{ rs.close(); pstmt.close(); conn.close(); }catch(Exception e){} } %> <% if(flag){ %> <jsp:forward page="login_success.jsp"> <jsp:param name="uname" value="<%=name%>"/> </jsp:forward> <% } else { //登录失败 %> <jsp:forward page="login_failure.jsp"/> <% } %> </center> </body> </html>
2,login_failure.jsp.文件
<%@ page language="java" contentType="text/html" pageEncoding="GBK"%> <%@ page import = "java.sql.*;"%> <html> <head><title>www.baidu.com,这是一个学习的好网站</title></head> <body> <center> <h1>登录操作</h1> <h2>登录失败,请重新<a href="login.jsp">登录</a>!</h2> </center> </body> </html>
3,login_success.jsp文件
<%@ page language="java" contentType="text/html" pageEncoding="GBK"%> <%@ page import = "java.sql.*;"%> <html> <head><title>www.baidu.com,这是一个学习的好网站</title></head> <body> <center> <h1>登录操作</h1> <h1>登录成功<h1> <h1>欢迎<font color="red"><%=request.getParameter("uname")%></font>光临!<h1> </center> </body> </html>
4,login.jsp登录页面:
<%@ page language="java" contentType="text/html" pageEncoding="GBK"%> <%@ page import = "java.sql.*;"%> <html> <head><title>www.baidu.com,这是一个学习的好网站</title></head> <body> <center> <h1>登录操作</h1> <hr> <form action="login_check.jsp" method="post"> <table border="1"> <tr> <td colspan="2"> 用户登录 </td> </tr> <tr> <td>登录ID:</td> <td><input type="text" name="id"></td> </tr> <tr> <td>登录密码:</td> <td><input type="password" name="password"></td> </tr> <tr> <td colspan="2"> <input type="submit" value="登录"> <input type="reset" value="重置"> </td> </tr> </table> </form> </center> </body> </html>
sql 脚本文件:
/*======================= 使用aaaa数据库 =======================*/ USE aaaa ; /*======================= 删除user数据表 =======================*/ DROP TABLE IF EXISTS user ; /*======================= 创建user数据表 =======================*/ CREATE TABLE user( userid VARCHAR(30) PRIMARY KEY , name VARCHAR(30) NOT NULL , password VARCHAR(32) NOT NULL ) ; /*======================= 插入测试数据 =======================*/ INSERT INTO user (userid,name,password) VALUES ('admin','administrator','admin') ;