实验四 JDBC技术
一、实验目的:
1、熟悉MySQL的安装配置方法;熟悉JDBC的基本编程方法;掌握 web程序中对数据库进行增删改查操作的方法;
2、理解 JSP+JavaBean+Servlet综合应用中如何进行数据库编程。
二、实验原理:
<略>
三、实验内容:
1、设计持久化JavaBean类, 设计数据库表结构,存储该JavaBean对象。 并编写用户界面实现数据的CRUD过程。
2、用户登录(JSP+JavaBean+MySQL)
将连接数据库验证用户名和密码的代码封装在 JavaBean 中,很大程度上减少了 JSP 文件中的 Java 代码量,实现了业务逻辑和表现形式的分离。系统由用户表 user、用户类 User 和 3 个 JSP 页面构成(用户登录页面 input.jsp、处理用户登录页面login.jsp,欢迎页面 welcome.jsp)
代码:
bean
package 实验四.bean;
public class User {
private Integer uid;
private String username;
private String password;
public Integer getUid() {
return uid;
}
public void setUid(Integer uid) {
this.uid = uid;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
dao
package 实验四.dao;
import 实验四.bean.User;
import java.sql.*;
public class UserDao {
private Connection conn = null;
public UserDao(){
}
private void initConnection() throws Exception {
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/cms";
this.conn = DriverManager.getConnection(url, "root", "root");
}
public User selectUserbyusername(String username) throws Exception {
User users = null;
this.initConnection();
String sql = "select username,password from t_user1" +
" where username=?";
PreparedStatement ps = this.conn.prepareStatement(sql);
ps.setString(1,username);
ResultSet rs = ps.executeQuery();
if (rs.next()) {
users = new User();
users.setUsername(rs.getString("username"));
users.setPassword(rs.getString("password"));
}
this.conn.close();
return users;
}
}
input.jsp
<%@ page import="实验四.dao.UserDao" %>
<%@ page import="实验四.bean.User" %><%--
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User: lenovo
Date: 2019/12/12
Time: 21:58
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--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<%
request.setCharacterEncoding("UTF-8");
String uname=request.getParameter("username");
String password = request.getParameter("pas