Running open layer with JSF and .xhtml file

问题

I made a jsf project and have the following example from http://docs.openlayers.org/library/introduction.html but as a xhtml file this wouldn't run and as a html file it would run. How to run it with jsf and .xhtml. It runs with html though.

     <?xml version="1.0" encoding="UTF-8"?>
<!--
To change this template, choose Tools | Templates
and open the template in the editor.
-->
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html">
    <h:head>
        <script src="http://openlayers.org/api/OpenLayers.js"></script>

    </h:head>
    <h:body>
        <div style="width:100%; height:100%" id="map"></div>
        <script defer="defer" type="text/javascript">
        var map = new OpenLayers.Map('map');
        var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS",
            "http://vmap0.tiles.osgeo.org/wms/vmap0", {layers: 'basic'} );
        var dm_wms = new OpenLayers.Layer.WMS(
            "Canadian Data",
            "http://www2.dmsolutions.ca/cgi-bin/mswms_gmap",
            {
                layers: "bathymetry,land_fn,park,drain_fn,drainage," +
                        "prov_bound,fedlimit,rail,road,popplace",
                transparent: "true",
                format: "image/png"
            },
            {isBaseLayer: false}
        );
        map.addLayers([wms, dm_wms]);
        map.zoomToMaxExtent();
      </script>
    </h:body>
</html>

Result at browser using firebug:

<head>
<body>
<div style="width: 100%; height: 100%; " id="map" class="olMap">
<div id="OpenLayers.Map_2_OpenLayers_ViewPort" style="position: relative; overflow-x: hidden; overflow-y: hidden; width: 100%; height: 100%; " class="olMapViewport olControlDragPanActive olControlZoomBoxActive olControlPinchZoomActive olControlNavigationActive">
<div id="OpenLayers.Map_2_events" style="position: absolute; width: 100%; height: 100%; z-index: 999; ">
<div id="OpenLayers.Control.PanZoom_5" style="position: absolute; left: 4px; top: 4px; z-index: 1004; " class="olControlPanZoom olControlNoSelect" unselectable="on">
<div id="OpenLayers.Control.ArgParser_6" style="position: absolute; z-index: 1004; " class="olControlArgParser olControlNoSelect" unselectable="on"/>
<div id="OpenLayers.Control.Attribution_7" style="position: absolute; z-index: 1004; " class="olControlAttribution olControlNoSelect" unselectable="on"/>
</div>
</div>
<script defer="defer" type="text/javascript">

var map = new OpenLayers.Map('map');
        var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS",
            "http://vmap0.tiles.osgeo.org/wms/vmap0", {layers: 'basic'} );
        var dm_wms = new OpenLayers.Layer.WMS(
            "Canadian Data",
            "http://www2.dmsolutions.ca/cgi-bin/mswms_gmap",
            {
                layers: "bathymetry,land_fn,park,drain_fn,drainage," +
                        "prov_bound,fedlimit,rail,road,popplace",
                transparent: "true",
                format: "image/png"
            },
            {isBaseLayer: false}
        );
        map.addLayers([wms, dm_wms]);
        map.zoomToMaxExtent();
</script>
</body>
<script src="chrome-extension://bmagokdooijbeehmkpknfglimnifench/googleChrome.js"/>
</html>

回答1:

You're executing JavaScript code inline. This means that the JavaScript code is immediately executed as the webbrowser encounters the particular code line. At that point, the <div id="map"> does not exist in the HTML DOM tree yet! The browser namely parses and executes HTML/JS code from top to bottom.

You need to execute that JavaScript code after the <div id="map"> has been created and added to the HTML DOM tree. You could achieve it the following ways:

Move the <script> block in the markup to after the <div id="map">:

<h:head>
    <script src="http://openlayers.org/api/OpenLayers.js"></script>
</h:head>
<body>
    <div style="width:100%; height:100%" id="map"></div>
    <script type="text/javascript">
        var map = new OpenLayers.Map('map');
        var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS",
        "http://vmap0.tiles.osgeo.org/wms/vmap0", {layers: 'basic'} );
        map.addLayer(wms);
        map.zoomToMaxExtent();
    </script>
</body>

Use window.onload to execute the code only when the browser is finished creating the HTML DOM tree.

<h:head>
    <script src="http://openlayers.org/api/OpenLayers.js"></script>
    <script type="text/javascript">
        window.onload = function() {
            var map = new OpenLayers.Map('map');
            var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS",
            "http://vmap0.tiles.osgeo.org/wms/vmap0", {layers: 'basic'} );
            map.addLayer(wms);
            map.zoomToMaxExtent();
        };
    </script>
</h:head>

This problem is not related to JSF or XHTML. It's just basic HTML/JS.

回答2:

I run int the same problem but my extentiong was .jspx. I did like this give it a try.

<html 
    xmlns="http://www.w3.org/1999/xhtml"
    xmlns:f="http://java.sun.com/jsf/core"  
    xmlns:h="http://java.sun.com/jsf/html"  
    xmlns:ui="http://java.sun.com/jsf/facelets"  
    xmlns:a4j="http://richfaces.org/a4j"
    xmlns:rich="http://richfaces.org/rich">  

<head>
<script src="http://piturralhpxp:1983/geoserver/openlayers/OpenLayers.js" type="text/javascript"></script>
        <script type="text/javascript">
     //<![CDATA[
          var map;
           etc ....
            //]]>
        </script>
        </head>
        <f:view>        
        <body onload="init()">

        </body>
</f:view>
</html>