My Html is of the form
<input type="hidden" name="SONGS" value="6242,6243,6289,6290,6291,6292,6293,6294,6295,6296,6297,6298,">
<tr>
<td>
01 - Big Love.WAV
</td>
<td>
<input type="text" name="6242TRACK" value="01">
</td>
<td>
<input type="text" name="6242ARTIST" value="Fleetwood Mac">
</td>
<td>
<input type="text" name="6242ARTIST_SORT" value="Fleetwood Mac">
</td>
<td>
<input type="text" name="6242TITLE" value="Big Love">
</td>
</tr>
<tr>
<td>
02 - Seven Wonders.WAV
</td>
<td>
<input type="text" name="6243TRACK" value="02">
</td>
<td>
<input type="text" name="6243ARTIST" value="Fleetwood Mac">
</td>
<td>
<input type="text" name="6243ARTIST_SORT" value="Fleetwood Mac">
</td>
<td>
<input type="text" name="6243TITLE" value="Seven Wonders">
</td>
</tr>
When user submits the form data it is processed using Spark framework. My logic was get the list of recnos from the SONGS input field, and then for each recNo browse the input fields starting with that recno. But its not working, I think I am misunderstanding how queryMaps work
protected void saveData(Request req)
{
String[] recNos = req.queryParams(EditSongsPage.SONGS).split(",");
for(String recNo:recNos)
{
System.out.println("recNo--------------"+recNo);
for(String next:req.queryMap(recNo).values())
{
System.out.println(next);
}
}
}
but this gives
recNo--------------6242
02/03/2018 08.58.22:GMT:com.jthink.songkong.server.callback.ServerEditSongs:startTask:SEVERE: null
java.lang.NullPointerException
at spark.QueryParamsMap.values(QueryParamsMap.java:262)
at com.jthink.songkong.server.callback.ServerEditSongs.saveData(ServerEditSongs.java:80)
at com.jthink.songkong.server.callback.ServerEditSongs.startTask(ServerEditSongs.java:52)
at com.jthink.songkong.server.CmdRemote.lambda$null$62(CmdRemote.java:171)
at spark.RouteImpl$1.handle(RouteImpl.java:72)
at spark.http.matching.Routes.execute(Routes.java:61)
at spark.http.matching.MatcherFilter.doFilter(MatcherFilter.java:130)
at spark.embeddedserver.jetty.JettyHandler.doHandle(JettyHandler.java:50)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1568)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.Server.handle(Server.java:564)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:317)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:279)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:110)
at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:124)
at org.eclipse.jetty.util.thread.Invocable.invokePreferred(Invocable.java:128)
at org.eclipse.jetty.util.thread.Invocable$InvocableExecutor.invoke(Invocable.java:222)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:294)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:199)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:673)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:591)
at java.lang.Thread.run(Thread.java:745)
A QueryMap copies the contents of request parameters from a HttpRequest and put the values into a map keyed by parameter name.
Because the contents of the HttpRequest are copied then the values of the querymap can be passed to a process on another thread and used accordingly, whereas the contents of the HttpRequest object are wiped once the page that recieved the request has sent back a HttpResponse.
That seems to be the main advantage of a QueryMap