Java Restful Web服务登录凭证失败

Question

So I built out a Java web service to connect to a mobile android app I'm developing. I'm new to Java & Android, and I'm have a bit of difficulty. I've got my android to send the login details to the Restful Web Service, but the restful web service fails when it tries to verify the details in the DB table made for users. I know it's the check credential issue because when I comment out the check credentials statement it will let me login. I can't figure out where I went wrong in the credential verification statement in my code, is someone could help out that would be great. The Login.class of my Restful service is below. Also I'm running everything off of tomcat7.

private boolean checkCredentials(String uname, String pwd){

        System.out.println("Inside checkCredentials");
        boolean result = false;
        if(Utitlity.isNotNull(uname) && Utitlity.isNotNull(pwd)){
            try {
                result = DBConnection.checkLogin(uname, pwd);
               // System.out.println("Inside checkCredentials try "+result);
            } catch (Exception e) {
                // TODO Auto-generated catch block
              //  System.out.println("Inside checkCredentials catch");
                result = false;
            }
        }else{
            System.out.println("Inside checkCredentials else");
            result = false;
        }

        return result;
    }

Answer 1

There are several issues with your code. The main one is that you handle any Exception thrown in the checkLogin() as just a regular "did not check out" case.

Do you really want to silently ignore any system failure, and handle it just like a valid business case?

I'm not saying that this is wrong in every case, but make it a explicit design decision, and at least log some information on the exception, so you can see that something is wrong.

Better yet, limit the catch-clause to the Exceptions you really expect to be thrown. (And even then, log information on the Exception!)

The usage of static methods like DBConnection.checkLogin() indicate more design problems. It might work, and be convenient in some cases, but it will bite you in the long run.

So, to find your immediate problem: print the stack trace of the Exception in the catch clause. Also log the result of the checkLogin() call right after the call, still in the try-block. If that information is printed, no Exception was thrown, and your problem lies within checkLogin() .