geotools隨筆

FeatureType

創(chuàng)建FeatureType

在創(chuàng)建一個(gè)新的Feature對(duì)象前要定義一個(gè)FeatureType

SimpleFeatureTypeBuilder b = new SimpleFeatureTypeBuilder();

//設(shè)置名字

b.setName( "Flag" );

//添加屬性

b.add( "name", String.class );

b.add( "classification", Integer.class );

b.add( "height", Double.class );

//add a geometry property

b.setCRS( DefaultGeographicCRS.WSG84 ); // set crs first

b.add( "location", Point.class ); // then add geometry

//build the type

final SimpleFeatureType TYPE = b.buildFeatureType();

或者

final SimpleFeatureType TYPE =

                DataUtilities.createType(

                        "Location",

                        "the_geom:Point:srid=4326,"

                        + // <- the geometry attribute: Point type

                        "name:String,"

                        + // <- a String attribute

                        "number:Integer" // a number attribute

                        );

        System.out.println("TYPE:" + TYPE);

修改FeatureType

抱歉，您沒法改，因?yàn)槠涫怯胒inal修飾的

但是，您可以創(chuàng)建一個(gè)新的FeatureType

SimpleFeatureType lineType = DataUtilities.createType("LINE", "geom:LineString,name:\"\",id:0");

SimpleFeatureTypeBuilder b = new SimpleFeatureTypeBuilder();

//使用預(yù)先存在的要素類型的狀態(tài)初始化生成器

b.init( lineType );

b.setName("POINT");

b.add(0, "geom", Point.class );

SimpleFeatureType pointType = b.buildFeatureType();

FeatureCollection

FeatureCollection的讀取

FeatureCollection無法通過foreach來讀取，F(xiàn)eatureCollection是對(duì)實(shí)時(shí)數(shù)據(jù)流的包裝；因此，我們需要確保在使用完后關(guān)閉迭代器。

try (SimpleFeatureIterator iterator = features.features()) {

            while (iterator.hasNext()) {

                SimpleFeature feature = iterator.next();

                // process feature

            }

        }

這里try的寫法和一般有些不同，它使用了try-with-resource結(jié)構(gòu)，會(huì)在try完畢后自動(dòng)關(guān)閉stream。

DataUtilities

DataUtilities是一個(gè)數(shù)據(jù)工具類，類似java里的util，全是靜態(tài)方法。

創(chuàng)建FeatureType

對(duì)于制作測(cè)試用例時(shí)快速創(chuàng)建 FeatureType 非常有用，有以下兩個(gè)方法

public static SimpleFeatureType createType(String typeName, String typeSpec)

public static SimpleFeatureType createType(String namespace, String name, String typeSpec)

快速創(chuàng)建一個(gè)FeatureType

SimpleFeatureType lineType = DataUtilities.createType("LINE", "centerline:LineString,name:\"\",id:0");

也可以選擇使用類名

SimpleFeatureType schema = DataUtilities.createType("EDGE", "edge:Polygon,name:String,timestamp:java.util.Date");

順便把參考系也加上

SimpleFeatureType lineType = DataUtilities.createType("LINE", "centerline:LineString:srid=32615,name:\"\",id:0");

使用命名空間

SimpleFeatureType lineType = DataUtilities.createType("http://somewhere.net/","LINE", "centerline:LineString,name:\"\",id:0");

修改FeatureType

無法修改，但可以創(chuàng)建一個(gè)副本

FeatureType schema = DataUtilities.createType("EDGE", "edge:Polygon,name:String");

System.out.println("1:"+schema.hashCode());

CoordinateReferenceSystem crs = CRS.decode( "EPSG:4326" );

schema = DataUtilities.createSubType((SimpleFeatureType) schema, null, crs );

System.out.println("2:"+schema.hashCode());

        FeatureType schema = DataUtilities.createType("EDGE", "edge:Polygon,name:String,timestamp:java.util.Date");

        System.out.println(schema);

        CoordinateReferenceSystem crs = CRS.decode( "EPSG:4326" );

        schema = DataUtilities.createSubType((SimpleFeatureType) schema, new String[]{"edge","name"}, crs );

        System.out.println(schema);