Notes

import java.sql.*;
import java.util.Scanner;

public class loginDemo {
static final String jd="com.mysql.jdbc.Driver";
static final String url="jdbc:mysql://localhost/java";
static final String user="root";
static final String pass="";
public static void createTable() throws SQLException {
Connection con=null;
Statement st=null;
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
try {
con= DriverManager.getConnection(url,user,pass);
st=con.createStatement();
String s = ("CREATE TABLE login"+"(username varchar(20)," + "password varchar(20))");
st.execute(s);
System.out.println("Table is Created Successfully");
} catch (SQLException e) {
e.printStackTrace();
}
finally
{
con.close();
st.close();
System.out.println("Finally All Done!!!");
}
}
public static void entre() throws SQLException {
Connection con = null;
Statement st = null;
Scanner scString = new Scanner(System.in);
Scanner scInt = new Scanner(System.in);
// System.out.println("You Wish to Enter Data");
int i = 1;
while (i != 0) {
System.out.println("Enter the User Name");
String username = scString.nextLine();
System.out.println("enter the Password");
String password = scString.nextLine();
// System.out.println("Enter the Student Address");
// String Stu_Add = scString.nextLine();
username = "'" + username + "'";
// Stu_Add = "'" + Stu_Add + "'";
password = "'" + password + "'";

try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
con = DriverManager.getConnection(url, user, pass);
st = con.createStatement();
String s = "insert into login values(" + username + "," + password + ")";
st.execute(s);
System.out.println("Want to enter data again");
i = scInt.nextInt();
st.close();
con.close();
}
}
public static void sqlinjection() throws SQLException {
Connection con = null;
Statement st = null;
Scanner scString = new Scanner(System.in);
Scanner scInt = new Scanner(System.in);
// System.out.println("You Wish to Enter Data");

System.out.println("Enter the User Name");
String username = scString.nextLine();
System.out.println("enter the Password");
String password = scString.nextLine();
username = "'" + username + "'";
// Stu_Add = "'" + Stu_Add + "'";
password = "'" + password + "'";
String q="select count(*) from login where username="+username+"and password="+password+"";
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
con = DriverManager.getConnection(url, user, pass);
st = con.createStatement();
ResultSet rs=st.executeQuery(q);
int cnt=0;
while (rs.next())
{
cnt=rs.getInt(1);
}
if(cnt==0)
{
System.out.println(" Invalid ");
}else
{
System.out.println(" valid ");
}
rs.close();
st.close();
con.close();
}


public static void main(String[] args) throws SQLException {
// createTable();
// entre();
sqlinjection();
}
}