PermGen space - maven m2e tomcat7(PermGen space - maven m2e tomcat7)

 我想我已经找到了问题（跳到简短答案的粗体文字）。 
 
 我在我的机器上尝试了一个示例，方法是在我的桌面上创建一个.html文件，然后将PHP代码段上传到局域网上的开发服务器。 这给了我与你完全相同的结果，也使用了Firefox（v3.5.7）。 
 
 我不是一个PHP人（更多的Python / Django），但我知道一些基本的PHP，你的代码看起来很好。 我通过大量的Google / JSON / Ajax示例搜索确认了这一点。 我尝试了在建议论坛中给出的每个选项，包括PHP中的各种缓存头选项和不同的JQuery方法，包括更改一些缓存选项以及尝试各种不同的选项。 没有不同。 
 
 我完全简化了PHP，只是返回一个单项JSON数组，没有任何其他条件或控制结构 - 没有乐趣。 
 
 最终我得到了绝望，并在IE 8中尝试了相同的文件。它工作了！ 在Safari中尝试过它 - 它有效！ 
 
 然后我变得偏执，并认为Firefox中可能存在一些棘手的会话问题或其他一些奇怪的问题所以我完全清除了我的Firefox历史并重新启动了浏览器。 没有不同。 
 
 这至少给了我一个不同的角度，我可以谷歌看看其他人是否有同样的问题。 确实他们有。 
 
 事实证明， 如果您在本地计算机上运行包含Ajax的HTML文件，即带有“file：//”前缀，Firefox由于某种原因将无法正确进行Ajax调用。 我将文件复制到我的开发服务器，与PHP文件位于同一位置（但仍然使用完整的地址作为Ajax URL），确定它有效！ 
 
 我并不完全理解Firefox与真正的本地文件和Ajax有什么不同，但它在外面变得轻松，我现在无法调查。 我确实查看了有关安全性的设置，但没有任何明显的跳出来。 我很想知道这是如何适应您的开发环境的设置方式的。 如果我有机会，我会进一步调查，并会更新这个答案。 
 
 如果“about：config”中有一些或其他选项可能包含答案，我不会感到惊讶。 

I think I've found the problem (skip to the bold text for the short answer).
 
I tried the example on my machine by creating an .html file on my desktop and uploading the PHP snippet to my dev server on the LAN. This gave me the exact same results as you, also with Firefox (v3.5.7).
 
I'm not a PHP guy (more Python / Django) but I do know some basic PHP and your code looked fine to me. I confirmed this with much Googling of PHP / JSON / Ajax example-seeking. I tried every option given in advice forums, including various caching header options in the PHP and different JQuery methods, including changing some of its cache options and also trying various different options. No difference.
 
I completely simplified the PHP to literally just return a single-item JSON array, without any other conditionals or control structures - no joy.
 
Eventually I got desperate and tried the same file in IE 8. It worked! Tried it in Safari - it worked!
 
I then got paranoid and thought there might be some sticky session issues in Firefox or some other oddity so I completely cleared my Firefox history and restarted the browser. No difference.
 
This at least gave me a different angle on what I could Google for to see if others had the same problem. Indeed they had.
 
It turns out that if you are running the HTML file containing the Ajax on your local machine, i.e. with a "file://" prefix, Firefox for some reason will not make the Ajax calls correctly. I copied the file up to my dev server, in the same location as the PHP file (but still using the full address as the Ajax URL) and sure enough it worked!
 
I don't fully understand what Firefox does differently with truly local files and Ajax, but it's getting light outside and I can't investigate right now. I did look through the settings regarding security but nothing obvious jumped out at me. I'd be very interested to know how this fits into how your dev environment is set up. I will investigate further later if I get a chance and will update this answer.
 
I wouldn't be surprised if there is some or other option in "about:config" that may contain the answer.