Question

我的Html格式为

     <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>

当用户提交表单数据时，使用Spark框架处理它。我的逻辑是从SONGS输入字段获取recnos列表，然后为每个recNo浏览以该recno开头的输入字段。但它不起作用，我认为我误解了queryMaps的工作方式

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);
           }
       }

    }

但这给出了

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)

Answer 1

QueryMap 从 HttpRequest 复制请求参数的内容，并将值放入由参数名称键入的地图中。

因为 HttpRequest 的内容被复制，所以querymap的值可以传递给另一个线程上的进程并相应地使用，而 HttpRequest 的内容一旦收到请求的页面发送回 HttpResponse ，就会擦除对象。

这似乎是 QueryMap

的主要优势

如何使用Java Spark Framework queryMaps？

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