Despite the apparent success of the code in Listing 13, there's still a problem — what if the server responds to your request and finishes processing, but reports an error?

虽然清单13中的代码看起来似乎不错，但是还有一个问题——如果服务器响应请求并完成了处理但是报告了一个错误怎么办？

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For example, you've certainly entered a request for a URL, typed the URL incorrectly, and received a 404 error code to indicate a page is missing.

比方说，您肯定遇到过输入了错误的URL请求而得到404错误码的情形，它表示该页面不存在。

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If the validation action fails, the DataPower Appliance will respond to the request with a failure message and the HTTP 500 error code back to the client that initially sent the XML document.

如果验证动作失败，DataPower Appliance将以一条失败消息响应请求，并将HTTP 500错误码返回给最初发送XML文档的客户机。

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