增删改查2020.10.7

<%@ page import=“java.sql.*” %> <%– Created by IntelliJ IDEA. User: 发 Date: 2020/10/7 Time: 8:02 To change this template use File | Settings | File Templates. –%>

<%@ page contentType=“text/html;charset=UTF-8” language=“java” %>

Title <% //加载数据库驱动 Class.forName("com.mysql.jdbc.Driver"); //建立数据库链接 String url="jdbc:mysql://10.3.22.1/jhy28?user=root&password=root"; Connection connection = DriverManager.getConnection(url,"root","root"); String sql="select * from user where username= ? and password=?";//使用？代替实际参数 PreparedStatement ps =connection.prepareStatement(sql); ps.setString(1,request.getParameter("username")); ps.setString(2,request.getParameter("paswword")); ResultSet rs =ps.executeQuery(); //遍历结果集数据 while (rs.next()) { out.print(rs.getString("username")+"-"+rs.getString(3)+"<br>"); // } //创建statement对象 //Statement stmt=connection.createStatement();

// String sql=“select * from user where username=’”+request.getParameter(“username”)+"’"; //select *from user where username=‘admin3’ or ‘1’=‘1’ //数据库注入 //执行查询 返回结果集

%>

 <%@ page import="java.sql.Connection" %> <%@ page import="java.sql.DriverManager" %> <%@ page import="java.sql.Statement" %> <%@ page import="java.sql.ResultSet" %> <%@ page import="com.media.bean.UserBean" %> <%-- Created by IntelliJ IDEA. User: 发 Date: 2020/10/7 Time: 8:31 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %>

<% //user对象实例化

UserBean user = new UserBean(); //给对象赋值 user.setUsername(request.getParameter("username")); user.setPassword(request.getParameter("password")); //数据库加载驱动 Class.forName("com.mysql.jdbc.Driver"); String url = "jdbc:mysql://10.3.22.1/jhy28？user=root&password=root"; //数据库地址；10.3.22.1/jhy28?user=root&password=root Connection connection = DriverManager.getConnection(url); //名称，密码； //执行sql语句； Statement stmt = connection.createStatement(); //执行增删改操作； // sql 插入语句值是字符串 必须使用单引号 String sql = "insert into user (username,password,gender,age) values('"+user.getUsername()+"','"+user.getPassword()+"','"+user.getGender()+"',"+user.getAge()+")"; //String sql = "update user set status = 3 where id = 11"; //String sql = "delete from user where id =15"; 执行sql语句时id 保证数据库中存在该数据 //使用Statement 对象执行sql语句 增删改的数据库操作使用executeUpdate

int count = stmt.executeUpdate(sql);

if (count == 0) { out.print(“注册成功”); } else { out.print(“注册失败”); }

%>

Title