请教书中例子一些技术性的问题
04-06-04
softxyz
由于本人才疏学浅,可能提出的一些问题会贻笑大方,但还是希望能给出一些指点。
第4章cms例子的web.xml中有如下代码
<filter>
<filter-name>Set Character Encoding</filter-name>
<filter-class>com.jdon.util.SetCharacterEncodingFilter</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>true</param-value>
</init-param>
</filter>
由于找不到这个类,是否可以将其完整删除?或者可以进行怎样的修改?
虽然不修改它也能够运行起来,我只是想知道正常情况(如果有它)会有和效果?
第4章cms例子的web.xml中有如下代码
<filter>
<filter-name>Set Character Encoding</filter-name>
<filter-class>com.jdon.util.SetCharacterEncodingFilter</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>true</param-value>
</init-param>
</filter>
由于找不到这个类,是否可以将其完整删除?或者可以进行怎样的修改?
虽然不修改它也能够运行起来,我只是想知道正常情况(如果有它)会有和效果?
banq
2004-06-07 17:43
可以删除,网上也有类似源码,这是取自网上的源码,如下:
import javax.servlet.*; import java.io.IOException; /** * <p>Filter that sets the character encoding to be used in parsing the * incoming request, either unconditionally or only if the client did not * specify a character encoding. Configuration of this filter is based on * the following initialization parameters:</p> * <ul> * <li><strong>encoding</strong> - The character encoding to be configured * for this request, either conditionally or unconditionally based on * the <code>ignore</code> initialization parameter. This parameter * is required, so there is no default.</li> * <li><strong>ignore</strong> - If set to "true", any character encoding * specified by the client is ignored, and the value returned by the * <code>selectEncoding()</code> method is set. If set to "false, * <code>selectEncoding()</code> is called <strong>only</strong> if the * client has not already specified an encoding. By default, this * parameter is set to "true".</li> * </ul> * * <p>Although this filter can be used unchanged, it is also easy to * subclass it and make the <code>selectEncoding()</code> method more * intelligent about what encoding to choose, based on characteristics of * the incoming request (such as the values of the <code>Accept-Language</code> * and <code>User-Agent</code> headers, or a value stashed in the current * user's session.</p> * * @author <a href="mailto:jwtronics@yahoo.com">John Wong</a> * * @version $Id: SetCharacterEncodingFilter.java,v 1.1 2002/04/10 13:59:27 johnwong Exp $ */ public class SetCharacterEncodingFilter implements Filter { // ----------------------------------------------------- Instance Variables /** * 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 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 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"); PropsUtil.ENCODING = this.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); } } <p class="indent"> |
猜你喜欢