Login for java not authenticating access for mysql database

Question

我已经设置了一个gui，该gui具有一个登录界面和一个存储用户名和密码的数据库，但是当我尝试在gui上登录时，即使我输入了数据库中的确切数据，它也给了我无效的登录信息。

Answer 1

Change your Sql Statement as

select userName,password from person where userName = ? and password = ? 

instead of

   select userName from person where userName = ? and password = ?

UPDATE

Infact you no need to check again username and password in java code, your query itself will tells you he/she is valid or not