Make sure folders exist.

enrich-citygml-with-greenarea/src/main/java/de/hft/stuttgart/citygml/green/osm/GreenEnricher.java

@@ -173,6 +173,7 @@ public class GreenEnricher implements Runnable
 			OsmData osmData = new OsmData();
 			String boundingBoxString = GreenEnricher.extractAndConvertBoundingBox(cityModel, osmData);
 			String boundingBoxBasename = boundingBoxString.replace(",", "__").replace('.', '_');
+			Files.createDirectories(cacheFolder);
 			Path osmCache = cacheFolder.resolve("osm_response_" + boundingBoxBasename + ".xml");
 			if (!Files.exists(osmCache)) {
 				System.out.println("Downloading OSM data for " + boundingBoxString);
@@ -206,6 +207,8 @@ public class GreenEnricher implements Runnable
 
 			String inputString = citygmlInput.getFileName().toString();
 			String inputPathWithoutFileEnding = inputString.substring(0, inputString.lastIndexOf('.'));
+			
+			Files.createDirectories(outputFolder);
 			Path outputPath = outputFolder.resolve(inputPathWithoutFileEnding + "_" + outputSuffix + ".gml");
 			System.out.println("Writing output file to " + outputPath);
 			writeCityGML(cityModel, outputPath);