GWT：检查URL是否已经死了 [英] GWT: Check if URL is dead

问题描述

我试图检查url（以字符串形式）是否返回404错误。然而，我似乎无法使用java.net.URL，并且我读了某处，GWT中不支持java.net？如果是这样，我该如何检查GWT中URL是否死亡？

非常感谢。

解决方案

你说得对。在客户端GWT中，您不能使用java.net.URL。查看 Google的JRE仿真参考资料，如果您不确定哪些部分是Java标准库可以与GWT一起使用。 理论上，可以通过AJAX请求来检查URL（请参阅 ）。 /javadoc/latest/com/google/gwt/http/client/RequestBuilder.htmlrel =nofollow> RequestBuilder ）。但是由于同源策略，浏览器可能会阻止这种尝试。

所以我认为你应该在你的应用程序服务器端实现检查（根据上面Roflcoptr在注释中提供的链接），并用 GWT-RPC 。

I'm trying to check if a url (in String form) returns 404 error. However, I can't seem to use java.net.URL, and I read somewhere that java.net is not supported in GWT? If so, how do I check if URL is dead or not in GWT?

Much appreciated.

解决方案

You are right. In client side GWT you cannot use java.net.URL. Take a look at Google's JRE Emulation Reference if you are unsure what parts of the Java standard library can be uses with GWT.

Theoretically it would be possible to check a URL with an AJAX request (see RequestBuilder). But due to the same origin policy it is likely that the browser prevents such an attempt.

So I think you should implement the check on your applications server side (according to the link provided by Roflcoptr above in the comments) and call that routine with GWT-RPC.

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