为什么不回显$ e-> getMessage（）; 打印错误消息

Question

I cant get this code to print the error message. I'm fairly new to php so go easy on me aha. I'm trying to make a register page for my website, feel free to request more of the code if it's required to help me.

try {
    //Username
    if(strlen($username) < 4) {
        throw new Exception('Username must be at least 4 Characters!');
    }
    if(strlen($username) > 16){
        throw new Exception('Username cannot be more than 15 characters!');
    }


    if(!ctype_alnum($username)) {
        throw new Exception('Username must only be letters or numbers');
    }

    // Password
    if(strlen($password) < 8) {
        throw new Exception('Password must be at least 8 characters!'); 
    }

    // email
    if(!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $email)){
        throw new Exception('Invalid Email!'); 
    }

    // secretcode
    if(strlen($secretcode) < 6) {
        throw new Exception('Secret Code is too short!'); 
    }

    if(strlen($secretcode) > 10) {
        throw new Exception('Secret Code is too long!'); 
    }

    //repassword
    if(strlen($password!=$repassword)) {
        throw new Exception('Passwords did not match');
    }


    // Submit to database
    echo 'ok';

} catch (Exception $e) {
    echo $e->getMessage();
}

Can't get echo to print out error message

Answer 1

This is a common issue when working with classes. Just add this one line at the very top but after namespace declaration

namespace My\Workspace;
use Exception; //<-- this one

class Myclass 
{
    try {
        //your code
    } catch (Exception $e) {
        echo $e->getMessage();
    }

}

This is because if you don't use use php will go looking in My\Workspace\Exception which obviously doesn't exists and therefore the catch will never run.

If you don't wish to add the use Exception; declaration, a simple shortcut would be to add a backward slash in front of Exception

catch (\Exception $e)