includetag.java

来自「jakarta-taglibs」· Java 代码 · 共 131 行

/*
 * Copyright 1999,2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 

package org.apache.taglibs.xsl;


import java.io.BufferedInputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.TagSupport;


/**
 * Include the contents of the specified page at this point in our output.
 * This tag is similar to <code>&lt;jsp:include&gt;</code>, but does not
 * cause the output to be sent directly to the servlet response.  Therefore,
 * it can be used to capture the content of the page as body content of
 * a surrounding tag in which we are nested.
 *
 * @author Craig R. McClanahan
 * @version $Revision: 1.2 $ $Date: 2004/03/08 02:41:31 $
 */

public class IncludeTag extends TagSupport {


    // ------------------------------------------------------------- Properties


    /**
     * The URI of the page or servlet to be included.
     */
    private String page = null;

    public String getPage() {
	return (this.page);
    }

    public void setPage(String page) {
	this.page = page;
    }


    // --------------------------------------------------------- Public Methods


    /**
     * Include the specified page or servlet's output at this point.
     *
     * @exception JspException if a JSP error occurs
     */
    public int doStartTag() throws JspException {

	// Validate the format of the "page" attribute
	// FIXME - deal with relative URIs like <jsp:include> does
	if (!page.startsWith("/"))
	    throw new JspException("Page value must start with '/'");

	// Set up the output stream to which we will write
	JspWriter out = pageContext.getOut();

	// Set up a URLConnection to read the requested page.  We cannot use
	// PageContext.include() because it writes directly to the output
	// stream that goes back to the client. :-(
	HttpServletRequest request =
	    (HttpServletRequest) pageContext.getRequest();
	StringBuffer url = new StringBuffer();
	url.append(request.getScheme());
	url.append("://");
	url.append(request.getServerName());
	if (request.getServerPort() != 80) {
	    url.append(':');
	    url.append(request.getServerPort());
	}
	if (request.getContextPath() != null)
	    url.append(request.getContextPath());
	url.append(page);	// FIXME - deal with relative page references
	URLConnection conn = null;
	try {
	    conn = (new URL(url.toString())).openConnection();
	    conn.setAllowUserInteraction(false);
	    conn.setDoInput(true);
	    conn.setDoOutput(false);
	    conn.connect();
	} catch (Exception e) {
	    throw new JspException("Error opening connection: " +
				   e.toString());
	}

	// Copy the contents of this URL
	try {
	    BufferedInputStream is =
		new BufferedInputStream(conn.getInputStream());
	    InputStreamReader in = new InputStreamReader(is);
	    while (true) {
		int ch = in.read();
		if (ch < 0)
		    break;
		out.write(ch);
	    }
	} catch (Exception e) {
	    throw new JspException("Error reading connection: " +
				   e.toString());
	}

	// Skip the body of this tag (which should be empty anyway)
	return (SKIP_BODY);

    }


}