Asp.net之Sql注入与Parameter对象

一.Sql注入实例

 using System;
 using System.Collections.Generic;
 using System.Data;
 using System.Data.SqlClient;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;

 namespace ConsoleApp5
 {
     class Program
     {
         static void Main(string[] args)
         {
             //创建连接字符串
             SqlConnectionStringBuilder strConn = new SqlConnectionStringBuilder();
             strConn.DataSource = "DESKTOP-0MBGCKA\\SQL2016";
             strConn.InitialCatalog = "Login";
             strConn.IntegratedSecurity = true;
             using (SqlConnection conn = new SqlConnection(strConn.ConnectionString))
             {
                 Console.WriteLine("请输入用户名:");
                 var username = Console.ReadLine();
                 Console.WriteLine("请输入密码:");
                 var password = Console.ReadLine();
                 try
                 {
                     string strSql = "select count(*) from users where (name='" + username + "') and (word='" + password + "')";
                     SqlCommand cmd = new SqlCommand(strSql, conn);
                     conn.Open();
                     int row = (int)cmd.ExecuteScalar();
                     )
                     {
                         Console.WriteLine("登陆成功");
                     }
                     else
                     {
                         Console.WriteLine("登录失败");
                     }
                 }
                 catch (Exception ex)
                 {
                     Console.WriteLine("\nError:\n{0}", ex.Message);
                 }
             }
             Console.Read();
         }
     }
 }

Sql注入的原理:通过单引号破坏Sql语句的结构,从而使得输入的内容能够被当做Sql语句执行

二.Parameter对象

防止Sql注入的原理:将输入的内容作为字符串处理,不能够破坏Sql语句的结构,使得输入内容不能被当做Sql语句执行

实例:

 using System;
 using System.Collections.Generic;
 using System.Data;
 using System.Data.SqlClient;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;

 namespace ConsoleApp5
 {
     class Program
     {
         static void Main(string[] args)
         {
             //创建连接字符串
             SqlConnectionStringBuilder strConn = new SqlConnectionStringBuilder();
             strConn.DataSource = "DESKTOP-0MBGCKA\\SQL2016";
             strConn.InitialCatalog = "Login";
             strConn.IntegratedSecurity = true;
             using (SqlConnection conn = new SqlConnection(strConn.ConnectionString))
             {
                 Console.WriteLine("请输入用户名:");
                 var username = Console.ReadLine();
                 Console.WriteLine("请输入密码:");
                 var password = Console.ReadLine();
                 try
                 {
                     SqlParameter[] paras = new SqlParameter[] {
                         ),
                         )
                     };
                     paras[].Value = username;
                     paras[].Value = password;
                     string strSql = "Select count(*) from users where name= @username and word= @password";
                     SqlCommand cmd = new SqlCommand(strSql, conn);
                     cmd.Parameters.Add(paras[]);
                     cmd.Parameters.Add(paras[]);
                     conn.Open();
                     int row = (int)cmd.ExecuteScalar();
                     )
                     {
                         Console.WriteLine("登录成功");
                     }
                     else
                     {
                         Console.WriteLine("登录失败");
                     }
                 }
                 catch (Exception ex)
                 {
                     Console.WriteLine("\nError:\n{0}", ex.Message);
                 }
             }
             Console.ReadLine();
         }
     }
 }