Servlet to JSP redirect

Znachi problema e slednia:

[линк]

Tova e edna html forma (bez znachenie kakvo shte se vuvede), imam edin servlet koito parse -va dannite ot neia i gi obrabotva a sled tova triabva da redirect -ne kum edno .jsp v koeto ima Applet. Znachi servlet redirect -va, no Appleta ne se zarajda. A kogato directno startiram .jsp -to Appleta si trugva normalno.

[линк]

Kak da redirect -na taka, che vsichko da e OK?

Ako servleta redirect-va - ne znam kva e pri4inata, no ako forwardva q znam - znam kak da se izbegne syshto. Takyv li e slu4aqt ?

Eyo nachina po koito go pravia:

RequestDispatcher rd = getServletContext().getRequestDispatcher ("/defaultroot/clientJSP.jsp");
rd.forward(request,response);

i taka poluchavam request i response ot Servlet -a v JSP -to

Да, значи ползваш forward() както и очаквах.
Проблема ти е доста често срещан.
Състои се в това че браузъра не знае нищо за това че пренасочваш към друга страница. Когато срещне аплет тага той се опитва да зареди клас файловете от местоположение относно адреса на който си мисли че е страницата. Но там няма такъв клас понеже това е адреса на пренасочващия сървлет. Това е доста често срещано - и за това w3c въведе тага <base> който да се използва при динамично генериране на страницата. Този таг обикновено се генерира динамично и показва къде къде всъщност е страницата за да може адреса й да се ползва като база при референции към картинки и в случая аплети. Ще ти пастна соурса от Struts таг-a който се грижи точно за това в следващото съобщение.

Надявам се това да ти помогне.

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* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation ([линк])."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
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* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
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package org.apache.struts.taglib.html;

import java.io.IOException;

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;

import org.apache.struts.Globals;
import org.apache.struts.util.MessageResources;
import org.apache.struts.util.RequestUtils;

/**
* Renders an HTML <base> element with an href
* attribute pointing to the absolute location of the enclosing JSP page. This
* tag is only valid when nested inside a head tag body. The presence
* of this tag allows the browser to resolve relative URL's to images,
* CSS stylesheets and other resources in a manner independent of the URL
* used to call the ActionServlet.
*
* @author Luis Arias <[email protected]>
* @author David Graham
* @version $Revision: 1.16 $ $Date: 2003/05/17 01:56:51 $
*/

public class BaseTag extends TagSupport {

/**
* The message resources for this package.
*/
protected static MessageResources messages =
MessageResources.getMessageResources(Constants.Package + ".LocalStrings");

/**
* The server name to use instead of request.getServerName().
*/
protected String server = null;

/**
* The target window for this base reference.
*/
protected String target = null;

public String getTarget() {
return (this.target);
}

public void setTarget(String target) {
this.target = target;
}

/**
* Process the start of this tag.
*
* @exception JspException if a JSP exception has occurred
*/
public int doStartTag() throws JspException {
HttpServletRequest request = (HttpServletRequest) pageContext.getRequest();
String serverName = (this.server == null) ? request.getServerName() : this.server;

String baseTag =
renderBaseElement(
request.getScheme(),
serverName,
request.getServerPort(),
request.getRequestURI());

JspWriter out = pageContext.getOut();
try {
out.write(baseTag);
} catch (IOException e) {
pageContext.setAttribute(Globals.EXCEPTION_KEY, e, PageContext.REQUEST_SCOPE);
throw new JspException(messages.getMessage("common.io", e.toString()));
}

return EVAL_BODY_INCLUDE;
}

/**
* Render a fully formed HTML &lt;base&gt; element and return it as a String.
* @param scheme The scheme used in the url (ie. http or https).
* @param serverName
* @param port
* @param uri The portion of the url from the protocol name up to the query
* string.
* @return String An HTML &lt;base&gt; element.
* @since Struts 1.1
*/
protected String renderBaseElement(
String scheme,
String serverName,
int port,
String uri) {

StringBuffer tag = new StringBuffer("<base href=\"");
tag.append(scheme);
tag.append("://");

tag.append(serverName);
if ("http".equals(scheme) && (port == 80)) {
;
} else if ("https".equals(scheme) && (port == 443)) {
;
} else {
tag.append(":");
tag.append(port);
}

tag.append(uri);
tag.append("\"");

if (this.target != null) {
tag.append(" target=\"");
tag.append(this.target);
tag.append("\"");
}

if (RequestUtils.isXhtml(this.pageContext)) {
tag.append(" />");
} else {
tag.append(">");
}

return tag.toString();
}

/**
* Returns the server.
* @return String
*/
public String getServer() {
return this.server;
}

/**
* Sets the server.
* @param server The server to set
*/
public void setServer(String server) {
this.server = server;
}

}