[求助]mapxtreme for java4.7 在servlet里打开现有页面的问题

<P>在servlet里有下面的方法，通过鼠标点击一个点（这个点代表一棵树，城市的里树），并把该点渲染，然后打开一个jsp页面，显示这个树的详细信息。现在我不能打开这个详细信息页，请给予帮助！谢谢！</P>
<P>private void SelectElement(MapJ myMap, HttpServletRequest req,<BR>   HttpServletResponse res, DoublePoint newPoint) {</P>
<P>  try {<BR>//   res.setContentType("text/html");<BR>//   PrintWriter out = res.getWriter();<BR>   ArrayList resList = new ArrayList();<BR>   ArrayList<String> tt = new ArrayList<String>();<BR>   tt.add("dd");<BR>   FeatureSet fSet = null;<BR>   FeatureLayer tLayer = (FeatureLayer) myMap.getLayers().get(<BR>     "树木");<BR>   // 判断图层是否可选，如果不可选，设置其属性可选<BR>   if (!tLayer.isSelectable()) {<BR>    tLayer.setSelectable(true);<BR>   }<BR>   // Create a SelectionTheme<BR>   SelectionTheme selTheme = (SelectionTheme) tLayer.getThemeList()<BR>     .getTheme("PointSel");<BR>   // Create a Selection object, and add the selected features<BR>   Selection sel = new Selection();<BR>   // 判断该选中专题图层存在不存在<BR>   if (selTheme == null) {<BR>    selTheme = new SelectionTheme("PointSel");<BR>   } else {<BR>    // 删除以上操作已经删除的theme列表<BR>    tLayer.getThemeList().remove(selTheme);<BR>    selTheme = new SelectionTheme("PointSel");<BR>   }<BR>   // 保存图元属性<BR>   ArrayList colList = new ArrayList();<BR>   colList.add("treecode");// 增加想要取回的数据列<BR>   try {<BR>    // Select a feature at the specified location<BR>    fSet = tLayer.searchAtPoint(colList, newPoint, null);<BR>    // Assign the display style of the SelectionTheme<BR>    Rendition rend = RenditionImpl.getDefaultRendition();<BR>    rend.setValue(Rendition.SYMBOL_MODE, Rendition.SymbolMode.FONT);<BR>    rend.setValue(Rendition.FONT_FAMILY, "MapInfo Symbols");<BR>    rend.setValue(Rendition.FONT_SIZE, 9);<BR>    rend.setValue(Rendition.SYMBOL_STRING, String<BR>      .valueOf((char) 35));<BR>    rend.setValue(Rendition.SYMBOL_FOREGROUND, Color.RED);<BR>    Feature ftr = null;<BR>    while ((ftr = fSet.getNextFeature()) != null) {<BR>     sel.add(ftr);<BR>//     resList.add(ftr.getAttribute(colList.indexOf("BDZ_CODE")));<BR>//     resList.add(ftr.getAttribute(colList.indexOf("POLE_ID")));<BR>//     if (ftr.getAttribute(0) != null) {<BR>//      resList.add(ftr.getAttribute(0).toString());<BR>//     }<BR>     code=ftr.getAttribute(colList.indexOf("treecode")).toString();<BR>     req.getSession().setAttribute("code", code);<BR>     //getServletContext().getRequestDispatcher("/TreeInfo/TreeInfoDetail.jsp?treeid=" + Treeid + ";;thid=" + tid + "").forward(req,res);<BR>    }<BR>//    for (int j = 0; j < resList.size(); j++) {<BR>//     System.out.println(resList.get(j).toString());<BR>//    }<BR>    selTheme.setRendition(rend);<BR>    // Assign the Selection object to the SelectionTheme<BR>    selTheme.setSelection(sel);<BR>    // Add the SelectionTheme to the layer's list of themes<BR>    tLayer.getThemeList().add(selTheme);<BR>   } catch (Exception e) {<BR>    System.out.println("error");<BR>   } finally {<BR>    if (fSet != null) {<BR>     fSet.dispose();<BR>     fSet = null;<BR>    }<BR>   }<BR>   // myMap.setCenter(newpoint);<BR>   req.getSession().setAttribute("mapJ", myMap);<BR>   <BR>   resImg(myMap, res);<BR>   <BR>  } catch (Exception e) {<BR>   System.out.println("选择图元报错");<BR>  }<BR> }</P>