www.pudn.com > chap8.rar > TemplateServlet.java

package chap8; 
 
import com.oreilly.javaxslt.util.StylesheetCache; 
import java.io.*; 
import java.net.*; 
import javax.servlet.*; 
import javax.servlet.http.*; 
import javax.xml.transform.*; 
import javax.xml.transform.stream.*; 
 
/** 
 * Applies a standard stylesheet to every XML page on a site. 
 */ 
public class TemplateServlet extends HttpServlet { 
    private String xsltFileName; 
 
    /** 
     * Locate the template stylesheet during servlet initialization. 
     */ 
    public void init() throws UnavailableException { 
        ServletContext ctx = getServletContext(); 
        this.xsltFileName = ctx.getRealPath( 
                    "/WEB-INF/xslt/templatePage.xslt"); 
        File f = new File(this.xsltFileName); 
 
        if (!f.exists()) { 
            throw new UnavailableException( 
                    "Unable to locate XSLT stylesheet: " 
                    + this.xsltFileName, 30); 
        } 
    } 
 
    public void doGet(HttpServletRequest req, HttpServletResponse res) 
            throws ServletException, IOException { 
        try { 
            // use the ServletContext to locate the XML file 
            ServletContext ctx = getServletContext(); 
            String xmlFileName = ctx.getRealPath("/WEB-INF/xml" 
                    + req.getPathInfo()); 
 
            // verify that the file exists 
            if (!new File(xmlFileName).exists()) { 
                res.sendError(HttpServletResponse.SC_NOT_FOUND, xmlFileName); 
            } else { 
                res.setContentType("text/html"); 
 
                // load the XML file 
                Source xmlSource = new StreamSource(new BufferedReader( 
                        new FileReader(xmlFileName))); 
 
                // use a cached version of the XSLT 
                Transformer trans = 
                        StylesheetCache.newTransformer(xsltFileName); 
                trans.transform(xmlSource, new StreamResult(res.getWriter())); 
            } 
        } catch (TransformerConfigurationException tce) { 
            throw new ServletException(tce); 
        } catch (TransformerException te) { 
            throw new ServletException(te); 
        } 
    } 
}