| 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 |
|
|