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POCan I redirect to a valid Wicket page when attempting to access a non-existent page?
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  1. POCan I redirect to a valid Wicket page when attempting to access a non-existent page?
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    copied!<p><strong>Introduction</strong></p> <p>If a user of my Apache Wicket web application (which runs on GAE/J) attempts to visit a non-existent page, for example:</p> <pre><code>http://[MyURL]/admin/PageSubscribeX </code></pre> <p>the web framework logs the following warning:</p> <pre><code>org.apache.wicket.core.util.lang.WicketObjects resolveClass: Could not resolve class [[...].admin.PageSubscribeX] java.lang.ClassNotFoundException: [...].admin.PageSubscribeX at com.google.appengine.runtime.Request.process-78915baf06af5f31(Request.java) at java.lang.Class.forName(Class.java:133) at org.apache.wicket.application.AbstractClassResolver.resolveClass(AbstractClassResolver.java:108) at org.apache.wicket.core.util.lang.WicketObjects.resolveClass(WicketObjects.java:71) at org.apache.wicket.core.request.mapper.AbstractComponentMapper.getPageClass(AbstractComponentMapper.java:139) at org.apache.wicket.core.request.mapper.PackageMapper.parseRequest(PackageMapper.java:148) ... at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:458) at java.lang.Thread.run(Thread.java:679) </code></pre> <p>and GAE/J responds with an error 404 page and the text <code>Error: NOT_FOUND</code>.</p> <p>I know that currently with GAE/J I "cannot customize the 404 response page when no servlet mapping is defined for a URL".</p> <p><strong>My question</strong></p> <p>Is there any way I can specify a Wicket page for the response when no servlet mapping is defined for a URL? Alternatively, is there some servlet mapping I can define to map "all URLs not found" to a Wicket page of my choice?</p> <p>My software environment is:</p> <ul> <li>Wicket: 6.2.0</li> <li>GAE/J: 1.7.3</li> <li>Java: 1.6.0_37.</li> </ul> <p><strong>A failed attempt</strong></p> <p>Following the comments of @biziclop, I have tried the following, but this failed. All I got was my error page PageError showing every time....</p> <p>My code in my <code>WebApplication#init()</code> was:</p> <pre><code>ICompoundRequestMapper crmRoot = getRootRequestMapperAsCompound(); URLNotFoundMapper mapperURLNotFound = new URLNotFoundMapper(null, PageError.class); crmRoot.add(mapperURLNotFound); setRootRequestMapper(crmRoot); </code></pre> <p>My new mapper <code>URLNotFoundMapper</code> was</p> <pre><code>/** * This mapper class is intended to be the mapper of last resort, to be used * if all other mappers cannot handle the URL of the current request. * &lt;br/&gt; * This mapper will cause a defined (error) page to be shown. */ public class URLNotFoundMapper extends BookmarkableMapper { private IRequestMapper m_rmRoot = null; private Class&lt;? extends IRequestablePage&gt; m_classPage = null; /** * Constructor. * @param rmRoot * The application's previous root request mapper. * If this is &lt;code&gt;null&lt;/code&gt; then it is ignored. * @param clError * The class of the page which should handle erroneous requests. * This must not be &lt;code&gt;null&lt;/code&gt;. */ public URLNotFoundMapper(IRequestMapper rmRoot, final Class&lt;? extends IRequestablePage&gt; clError) { m_rmRoot = rmRoot; m_classPage = clError; } /** * Use this mapper as the last option. * So let all other mappers try to handle the request first. * @param request * The request. * @return * The score of the application's previous root request mapper. */ @Override public int getCompatibilityScore(Request request) { return Integer.MIN_VALUE; } /** * This method returns an &lt;code&gt;IRequestHandler&lt;/code&gt; for the bookmarkable * error page. * @param request * @return * An &lt;code&gt;IRequestHandler&lt;/code&gt; capable of processing a bookmarkable * request. * */ @Override public IRequestHandler mapRequest(Request request) { IRequestHandler rhResult = null; if (m_rmRoot != null) rhResult = m_rmRoot.mapRequest(request); if (rhResult != null) rhResult = null; // Another mapper can handle this else { rhResult = processBookmarkable(m_classPage, null); } return rhResult; } @Override public Url mapHandler(IRequestHandler requestHandler) { Url urlResult = null; if (m_rmRoot != null) urlResult = m_rmRoot.mapHandler(requestHandler); if (urlResult != null) urlResult = null; // Another mapper can handle this else { PageInfo info = new PageInfo(); UrlInfo urlInfo = new UrlInfo(new PageComponentInfo(info, null), m_classPage, null); urlResult = buildUrl(urlInfo); } return urlResult; } /** * @return * The URL info for the bookmarkable error page. */ @Override protected UrlInfo parseRequest(Request request) { UrlInfo uiResult = null; uiResult = new UrlInfo(null, m_classPage, null); return uiResult; } } </code></pre>
 

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