FrameworkServlet.java 文件源码

/**
 * Delegate OPTIONS requests to {@link #processRequest}, if desired.
 * <p>Applies HttpServlet's standard OPTIONS processing otherwise,
 * and also if there is still no 'Allow' header set after dispatching.
 * @see #doService
 */
@Override
protected void doOptions(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

    if (this.dispatchOptionsRequest || CorsUtils.isPreFlightRequest(request)) {
        processRequest(request, response);
        if (response.containsHeader("Allow")) {
            // Proper OPTIONS response coming from a handler - we're done.
            return;
        }
    }

    // Use response wrapper for Servlet 2.5 compatibility where
    // the getHeader() method does not exist
    super.doOptions(request, new HttpServletResponseWrapper(response) {
        @Override
        public void setHeader(String name, String value) {
            if ("Allow".equals(name)) {
                value = (StringUtils.hasLength(value) ? value + ", " : "") + RequestMethod.PATCH.name();
            }
            super.setHeader(name, value);
        }
    });
}