How to validate username from MySql with JSP
un//be the variable where username entered now from html form is stored

uname //column name in mysql for usernames
user //table name in mysql

Connection con = DriverManager.getConnection("jdbc:mysql://localhost/mebps","root","admin");
Statement stmt = (Statement) con.createStatement();
ResultSet rs = stmt.executeQuery("select un from userinfo");

while(rs.next())
{
if(rs.getString("uname") == un)
{
out.println("user is present");
}
}