如果用户在尝试访问这个资源时还没有经过身份验证，那么用户会收到401状态码，应用程序可以提供一个特殊的错误处理函数来处理这种情况。

If a user is not authenticated when trying to access this resource, the user will receive a 401 status code and the application can provide a special error handler to deal with that condition.

youdao

如果就绪状态是 4 而且状态码是 200，就可以处理服务器的数据了，而且这些数据应该就是要求的数据（而不是错误或者其他有问题的信息）。

With a ready state of 4 and a status code of 200, you're ready to process the server's data and that data should be what you asked for (and not an error or other problematic piece of information).

youdao

为了增加更健壮的错误处理并尽量避免过于复杂，可以增加一两个状态码检查，请看一看 清单 15 中修改后的 updatePage() 版本。

To add more robust error handling -- with minimal complication -- you might add a check or two for other status codes; check out the modified version of updatePage() in Listing 15.

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