Nginx使用反向代理時 Hessian 的 411 錯誤解決方案【轉】
問題描述：
用 Hessian 實現 web service 過程中，需要建立物件時，是使用 HTTP POST 方法來傳遞資料的。但是在有反向代理 (nginx) 的情況下，會丟擲異常 (com.caucho.hessian.client.HessianConnectionException: 411:java.io.IOException: Server returned HTTP response code: 411 for URL:http://xxxx/xxx/xxxService) 。
首先來看下 HTTP 411 錯誤的解釋： Length Required
解決方法：
com.caucho.hessian.client.HessianProxyFactory 類中，有一個 boolean _chunckedPost 的域成員，其預設值為 true 。這個值就是規定 Hessian
分塊編碼傳輸：
分塊編碼 (chunked encoding) 傳輸方式是 HTTP 1.1 協議中定義的 Web 使用者向伺服器提交資料的一種方法，當伺服器收到 chunked 編碼方式的資料時會分配一個緩衝區存放之，如果提交的資料大小未知，客戶端會以一個協商好的分塊大小向伺服器提交資料。
The content can be broken up into a number of chunks; each of which is prefixed by its size in bytes. A zero size chunk indicates the end of the response message. If a server is using chunked encoding it must set the Transfer-Encoding header to "chunked".
Chunked encoding is useful when a large amount of data is being returned to the client and the total size of the response may not be known until the request has been fully processed. An example of this is generating an HTML table of results from a database query. If you wanted to use the Content-Length header you would have to buffer the whole result set before calculating the total content size. However, with chunked encoding you could just write the data one row at a time and write a zero sized chunk when the end of the query was reached.
如果不使用 Chunked encoding 傳輸方式，需要將要傳送的資料快取下來，計算出 content-length ，從而滿足反向代理（ Nginx ）需要 content-length 的要求。
轉自：http://www.oschina.net/question/54100_20352