java list转为数组以及hashmap对key排序的用法

java list转为数组的用法
List tlist=new ArrayList();
String[] sArray=new String[tlist.size()];
tlist.toArray(sArray);

//geowave 中如下例子：分解多个Geometry json string split char '#'   
        List<Geometry> geoList=new ArrayList<Geometry>();
        String[] geoStrArray=geojson.split("#");
        for(String geo_str :geoStrArray)
        {
            GeoJsonReader gjR=new GeoJsonReader();
            Geometry t_geo=gjR.read(geo_str);
            geoList.add(t_geo);
            System.out.println(geo_str);
        }
        Geometry[] geoArray=new Geometry[geoList.size()];
        geoList.toArray(geoArray);
        GeometryFactory geoFact=new GeometryFactory(new PrecisionModel(),srid);
        Geometry geoColl=new GeometryCollection(geoArray,geoFact);
        //
        Geometry geo=geoColl;

hashmap对key排序的用法

//map中的key是没有排序的
Map<String,Double> map=new HashMap<String,Double>();
map.put(fdvalue,area);   //添加或修改
map.remove(fdvalue);    //删除

//sortMap中的key是已排序的
SortedMap<String,Double> sortMap=new TreeMap<String,Double>(map);
Set<String> keyset=sortMap.keySet();
for (String key : keyset) {
            area=sortMap.get(key);
            System.out.println(key+"="+area);
}

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