jts2geojson

Add the following dependency to your pom.xml to use the jts2geojson library in your Java project.

<dependency>
    <groupId>org.wololo</groupId>
    <artifactId>jts2geojson</artifactId>
    <version>0.18.1</version>
</dependency>

Use GeoJSONWriter to serialize JTS Geometry objects into GeoJSON objects, and GeoJSONReader to deserialize GeoJSON back into JTS Geometry objects. The API follows the standard JTS io.* pattern.

  GeoJSONWriter writer = new GeoJSONWriter();
  GeoJSON json = writer.write(geometry);
  String jsonstring = json.toString();

  GeoJSONReader reader = new GeoJSONReader();
  Geometry geometry = reader.read(json);

You can create a FeatureCollection by building a list of Feature objects (each containing a Geometry and a Map<String, Object> of properties) and passing that list to GeoJSONWriter.write().

  // create and serialize a FeatureCollection
  List<Features> features = new ArrayList<Features>();
  Map<String, Object> properties = new HashMap<String, Object>();
  features.add(new Feature(geometry, properties));
  GeoJSONWriter writer = new GeoJSONWriter();
  GeoJSON json = writer.write(features);

While JTS does not natively support GeoJSON Feature or FeatureCollection types, this library provides GeoJSONFactory to parse them. You can cast the result of GeoJSONFactory.create(json) to Feature or FeatureCollection to access their properties and geometries.

  // parse Feature or FeatureCollection
  Feature feature = (Feature) GeoJSONFactory.create(json);
  FeatureCollection featureCollection = (FeatureCollection) GeoJSONFactory.create(json);

  // parse Geometry from Feature
  GeoJSONReader reader = new GeoJSONReader();
  Geometry geometry = reader.read(feature.getGeometry());
  geometry = reader.read(featureCollection.getFeatures()[0].getGeometry());