进行RESTful API设计的时候，一般想将POST GET PUT DELETE所用到的参数，倾向于使用结构化数据来描述，如使用JSON或XML，若是放到HTTP BODY中看起来漂亮，Server端获取这些参数的方式也能一致。

但是，对于GET请求，不能将参数放在HTTP BODY中。
这里有个关注度很高的激烈讨论：http://stackoverflow.com/questions/978061/http-get-with-request-body
结论是：你可以在GET请求中带有HTTP BODY内容，但是服务端不应该解析它，否则有悖HTTP 1.1规范。

即算你自己开发的server支持了此种情况的解析，也不能保证其他server或代理服务器支持。

这是HTTP 规范的主要创作人之一 Roy T. Fielding 的观点：

Yes. In other words, any HTTP request message is allowed to contain a message body, and thus must parse messages with that in mind. Server semantics for GET, however, are restricted such that a body, if any, has no semantic meaning to the request. The requirements on parsing are separate from the requirements on method semantics.

So, yes, you can send a body with GET, and no, it is never useful to do so.

This is part of the layered design of HTTP/1.1 that will become clear again once the spec is partitioned (work in progress).

....Roy

via: https://groups.yahoo.com/neo/groups/rest-discuss/conversations/messages/9962

另外，不是所有客户端都支持发起带有body的HTTP GET请求，比如jQuery就直接限制了： http://bugs.jquery.com/ticket/8961