基于Google Maps与Ajax在Java Web集成地图信息（下）(1)

public class TouristSiteDirectoryServlet
 extends javax.servlet.http.HttpServlet
implements javax.servlet.Servlet {
...
/**
*数据存取对象提供了搜索旅游景点数据库的方法
*/
private SiteDAO getSiteDAO() {
...
}
/**
*提供的数据存取对象提供了搜索旅游景点数据库的方法 
*/
protected void doGet(HttpServletRequest request，
HttpServletResponse response)
throws ServletException， IOException {
String method=request.getParameter("method");
XStream xstream = new XStream();
xstream.alias("marker"， Marker.class);
response.setContentType("application/xml");
if (method == null) {
String id = request.getParameter("id");
Site site = getSiteDAO().findSiteById(id);
xstream.alias("site"， Site.class);
String xml = xstream.toXML(site);
response.getWriter().write(xml);
} else if (method.equals("findAll")) {
List sites = getSiteDAO().findAllAsMarkers();
String xml = xstream.toXML(sites);
response.getWriter().write(xml);
} else if (method.equals("findAllCities")) {
List cities = getSiteDAO().findAllCityAsMarkers();
String xml = xstream.toXML(cities);
response.getWriter().write(xml);
} else if (method.equals("findByCity")) {
String city = request.getParameter("city");
List sites = getSiteDAO().findByCityAsMarkers(city);
String xml = xstream.toXML(sites);
response.getWriter().write(xml);
}
}
}

<list>
<marker>
<id>3</id>
<name>The Famous Mud Baths of central Elbonia</name>
<latitude>-36.87</latitude>
<longitude>185.22</longitude>
</marker>
<marker>
<id>5</id>
<name>The North Elbonian Mud Baths</name>
<latitude>-36.77</latitude>
<longitude>185.92</longitude>
</marker>
...
</list>

<script language="javascript" type="text/javascript">
function loadSites() {
var request = GXmlHttp.create();
request.open("GET"， "/maps/SiteDirectory?method=findAll"， true);
request.onreadystatechange = getCallbackFunction(request， processSiteData);
request.send(null);
}
</script>

<script language="javascript" type="text/javascript">
function processSiteData(xmlDoc){
//取得标记数组并循环遍历它
siteMarkers = xmlDoc.documentElement.getElementsByTagName("marker");
displaySitesMarkers();
}
function displaySitesMarkers() {
map.clearOverlays();
for (var i = 0; i < siteMarkers.length; i++) {
//获得每个标记的属性
var lat = parseFloat(siteMarkers[i].getElementsByTagName("latitude")
[0].firstChild.nodeValue);
var lng = parseFloat(siteMarkers[i].getElementsByTagName("longitude")
[0].firstChild.nodeValue);
var id = siteMarkers[i].getElementsByTagName(
"id")[0].firstChild.nodeValue;
var label = siteMarkers[i].getElementsByTagName(
"name")[0].firstChild.nodeValue;
createSiteMarker(new GLatLng(lat，lng)，label，id);
}
}
</script>