package yidishui.util; 
	
	

		

	
	

		
import javax.servlet.Filter;
	
	

		
import javax.servlet.FilterChain;
	
	

		
import javax.servlet.FilterConfig;
	
	

		
import javax.servlet.ServletException;
	
	

		
import javax.servlet.ServletRequest;
	
	

		
import javax.servlet.ServletResponse;
	
	

		
import java.io.IOException; 
	
	

		

	
	

		
public class EncodingFilter implements Filter { 
	
	

		

	
	

		
/**
	
	

		
* The default character encoding to set for requests that pass through this
	
	

		
* filter.
	
	

		
*/
	
	

		
protected String encoding = null; 
	
	

		

	
	

		
/**
	
	

		
* 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 response The servlet response we are creating
	
	

		
* @param chain The filter chain we are processing
	
	

		
* @throws IOException if an input/output error occurs
	
	

		
* @throws 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
	
	

		
chain.doFilter(request, response); 
	
	

		

	
	

		
} 
	
	

		

	
	

		
/**
	
	

		
* 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
	
	

		
* @return return encoding
	
	

		
*/
	
	

		
protected String selectEncoding(ServletRequest request) { 
	
	

		

	
	

		
return (this.encoding); 
	
	

		

	
	

		
} 
	
	

		

	
	

		
}// EOC 
	
	

		

	
	

		

	

	

		
<filter>
	
	

		
<filter-name>EncodingFilter</filter-name>
	
	

		
<filter-class>yidishui.util.EncodingFilter</filter-class>
	
	

		
<init-param>
	
	

		
<param-name>encoding</param-name>
	
	

		
<param-value>UTF-8</param-value>
	
	

		
</init-param>
	
	

		
<init-param>
	
	

		
<param-name>ignore</param-name>
	
	

		
<param-value>yes</param-value>
	
	

		
</init-param>
	
	

		
</filter>
	
	

		
<filter-mapping>
	
	

		
<filter-name>EncodingFilter</filter-name>
	
	

		
<url-pattern>/*</url-pattern>
	
	

		
</filter-mapping>