etag and its filter

from spring 3:

You can re-write it with your requirement

---
So I have in web.xml:

Code:
  <filter>
    <filter-name>pageNotFoundFilter</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
  </filter>

and in my context.xml I have a bean called "pageNotFoundFilter". Very nice !

---

<filter>  
<filter-name>etagFilter</filter-name>  
<filter-class>org.xxx.web.filter.EtagHeaderFilter</filter-class>  
</filter>  

<filter-mapping>  
<filter-name>etagFilter</filter-name>  
</filter-mapping> 


ShallowEtagResponseWrapper responseWrapper = new ShallowEtagResponseWrapper(response);  
filterChain.doFilter(request, responseWrapper);  
 
byte[] body = responseWrapper.toByteArray();  
String responseETag = generateETagHeaderValue(body);  
response.setHeader(HEADER_ETAG, responseETag);  

String requestETag = request.getHeader(HEADER_IF_NONE_MATCH);  
if (responseETag.equals(requestETag)) {  
    if (logger.isTraceEnabled()) {  
        logger.trace("ETag [" + responseETag + "] equal to If-None-Match, sending 304");  
   }  
    response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);  
}  
else {  
    if (logger.isTraceEnabled()) {  
        logger.trace("ETag [" + responseETag + "] not equal to If-None-Match [" + requestETag +  
                "], sending normal response");  
    }  
    response.setContentLength(body.length);  
    FileCopyUtils.copy(body, response.getOutputStream());  
}