扩展入口Filter实现：
package lab.s2jh.core.web.sitemesh;
import org.sitemesh.DecoratorSelector;
import org.sitemesh.builder.SiteMeshFilterBuilder;
import org.sitemesh.config.ConfigurableSiteMeshFilter;
import org.sitemesh.webapp.WebAppContext;
/**
* 扩展实现注入基于request参数decorator值进行动态定位装饰器的选择器
*/
public class ParamConfigurableSiteMeshFilter extends ConfigurableSiteMeshFilter {
protected void applyCustomConfiguration(SiteMeshFilterBuilder builder) {
//获取原有默认配置装饰选择器
DecoratorSelector<WebAppContext> defaultDecoratorSelector = builder.getDecoratorSelector();
//赋给自定义装饰选择器，则自定义规则未匹配时调用默认选择器获取
builder.setCustomDecoratorSelector(new ParamDecoratorSelector(defaultDecoratorSelector));
}
}定制装饰选择器实现：
package lab.s2jh.core.web.sitemesh;
import java.io.IOException;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.lang3.StringUtils;
import org.sitemesh.DecoratorSelector;
import org.sitemesh.content.Content;
import org.sitemesh.webapp.WebAppContext;
/**
* 基于request参数decorator值进行动态定位装饰器的选择器
* 如果decorator参数有值，则返回"/WEB-INF/views/layouts/" + decorator + ".jsp"作为目标装饰模板页面
*/
public class ParamDecoratorSelector implements DecoratorSelector<WebAppContext> {
private DecoratorSelector<WebAppContext> defaultDecoratorSelector;
public ParamDecoratorSelector(DecoratorSelector<WebAppContext> defaultDecoratorSelector) {
this.defaultDecoratorSelector = defaultDecoratorSelector;
}
public String[] selectDecoratorPaths(Content content, WebAppContext context) throws IOException {
// build decorator based on the request
HttpServletRequest request = context.getRequest();
String decorator = request.getParameter("decorator");
if (StringUtils.isNotBlank(decorator)) {
//按照参数值返回对应路径下面的jsp装饰模板页码
return new String[] { "/WEB-INF/views/layouts/" + decorator + ".jsp" };
}
// Otherwise, fallback to the standard configuration
return defaultDecoratorSelector.selectDecoratorPaths(content, context);
}
}调整web.xml配置：
<filter>
<filter-name>sitemeshFilter</filter-name>
<filter-class>lab.s2jh.core.web.sitemesh.ParamConfigurableSiteMeshFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>sitemeshFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
