setCharactorEncoding

public class SetCharacterEncodingFilter implements Filter {

private static Log log = new Log(SetCharacterEncodingFilter.class);


// ----------------------------------------------------- Instance Variables


/**
* The default character encoding to set for requests that pass through
* this filter.
*/
protected String encoding = "UTF-8";


/**
* The filter configuration object we are associated with.  If this value
* is null, this filter instance is not currently configured.
*/
protected FilterConfig filterConfig = null;


/**
* Should a character encoding specified by the client be ignored?
*/
protected boolean ignore = true;


// --------------------------------------------------------- Public Methods


/**
* Take this filter out of service.
*/
public void destroy() {


this.encoding = null;
this.filterConfig = null;


}


/**
* Select and set (if specified) the character encoding to be used to
* interpret request parameters for this request.
*
* @param request The servlet request we are processing
* @param result The servlet response we are creating
* @param chain The filter chain we are processing
*
* @exception IOException if an input/output error occurs
* @exception ServletException if a servlet error occurs
*/
public void doFilter(
ServletRequest request,
ServletResponse response,
FilterChain chain)
throws IOException, ServletException {

// Conditionally select and set the character encoding to be used
if (ignore || (request.getCharacterEncoding() == null)) {
String encoding = selectEncoding(request);
if (encoding != null)
request.setCharacterEncoding(encoding);
}


// Pass control on to the next filter
if(request instanceof HttpServletRequest && response instanceof HttpServletResponse){
//update by zzx
if(chain!=null)
chain.doFilter(request, response);
else
request.setCharacterEncoding(encoding);
}
//


}


/**
* Place this filter into service.
*
* @param filterConfig The filter configuration object
*/
public void init(FilterConfig filterConfig) throws ServletException {


this.filterConfig = filterConfig;
this.encoding = filterConfig.getInitParameter("encoding");
String value = filterConfig.getInitParameter("ignore");
if (value == null)
this.ignore = true;
else if (value.equalsIgnoreCase("true"))
this.ignore = true;
else if (value.equalsIgnoreCase("yes"))
this.ignore = true;
else
this.ignore = false;




}


// ------------------------------------------------------ Protected Methods


/**
* Select an appropriate character encoding to be used, based on the
* characteristics of the current request and/or filter initialization
* parameters.  If no character encoding should be set, return
* <code>null</code>.
* <p>
* The default implementation unconditionally returns the value configured
* by the <strong>encoding</strong> initialization parameter for this
* filter.
*
* @param request The servlet request we are processing
*/
protected String selectEncoding(ServletRequest request) {


return (this.encoding);


}


}