is Jwt令牌是唯一的

我使用的是JWT网络令牌系统。我成功地生成了TOKENS。我正在Laravel中创建JWT代币，如下

我正在使用以下技术堆栈

• LARAVEL 5.2框架
• JWT（套装）

样本代码

use JWTAuth;
use Tymon'JWTAuth'Exceptions'JWTException;
class AuthenticateController extends Controller
{
    public function authenticate(Request $request)
    {
        // grab credentials from the request
        $credentials = $request->only('email', 'password');
        try {
            // attempt to verify the credentials and create a token for the user
            if (! $token = JWTAuth::attempt($credentials)) {
                return response()->json(['error' => 'invalid_credentials'], 401);
            }
        } catch (JWTException $e) {
            // something went wrong whilst attempting to encode the token
            return response()->json(['error' => 'could_not_create_token'], 500);
        }
        // all good so return the token
        return response()->json(compact('token'));
    }
}

样本输出

我得到

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ

问题1

生成的令牌是唯一的吗