我为我的应用程序不期望的每个条件创建了异常。UserNameNotValidException, PasswordNotCorrectException等。

然而,我被告知我不应该为这些条件创造例外。在我的UML中,那些是主要流程的异常,那么为什么它不应该是异常呢?

是否有创建异常的指导或最佳实践?


当前回答

安全性与您的示例混为一谈:您不应该告诉攻击者用户名存在,但密码是错误的。这是你不需要分享的额外信息。只要说“用户名或密码不正确”。

其他回答

我对异常的使用有哲学问题。基本上,您期待一个特定的场景发生,但不是明确地处理它,而是将问题推到“其他地方”处理。至于“其他地方”在哪里,谁也说不准。

我有三种情况。

Bad or missing input should not be an exception. Use both client side js and server side regex to detect, set attributes and forward back to the same page with messages. The AppException. This is usually an exception that you detect and throw with in your code. In other words these are ones you expect (the file does not exist). Log it, set the message, and forward back to the general error page. This page usually has a bit of info about what happened. The unexpected Exception. These are the ones you don't know about. Log it with details and forward them to a general error page.

希望这能有所帮助

其他人建议不应该使用异常,因为在正常流程中,如果用户输入错误,就会出现错误的登录。我不同意,我不明白其中的道理。与打开文件相比。如果该文件不存在或由于某种原因不可用,则框架将抛出异常。使用上述逻辑是微软的一个错误。他们应该返回一个错误代码。解析、webrequest等也一样。

I don't consider a bad login part of a normal flow, it's exceptional. Normally the user types the correct password, and the file does exist. The exceptional cases are exceptional and it's perfectly fine to use exceptions for those. Complicating your code by propagating return values through n levels up the stack is a waste of energy and will result in messy code. Do the simplest thing that could possibly work. Don't prematurely optimize by using error codes, exceptional stuff by definition rarely happens, and exceptions don't cost anything unless you throw them.

一个经验法则是在您通常无法预测的情况下使用异常。例如数据库连接、磁盘上丢失的文件等。对于您可以预测的场景,例如用户试图使用错误的密码登录,您应该使用返回布尔值的函数,并知道如何优雅地处理这种情况。您不希望仅仅因为有人输入了密码错误而抛出异常,从而突然结束执行。

异常与返回错误代码参数应该是关于流控制的,而不是哲学(错误有多“异常”):

void f1() throws ExceptionType1, ExceptionType2 {}

void catchFunction() {
  try{
    while(someCondition){
      try{
        f1(); 
      }catch(ExceptionType2 e2){
        //do something, don't break the loop
      }
    }
  }catch(ExceptionType1 e1){
    //break the loop, do something else
  }

}