Core Servlets and JavaServer Pages™

6.1. Specifying Status Codes

As just described, the HTTP response status line consists of an HTTP version, a status code, and an associated message. Since the message is directly associated with the status code and the HTTP version is determined by the server, all a servlet needs to do is to set the status code. The way to do this is by the setStatus method of HttpServletResponse. If your response includes a special status code and a document, be sure to call setStatus before actually returning any of the content via the PrintWriter. That's because an HTTP response consists of the status line, one or more headers, a blank line, and the actual document, in that order. The headers can appear in any order, and servlets buffer the headers and send ...