private Writer writerFor(File file) {
        if (!file.getParentFile().exists() && !file.getParentFile().mkdirs()) {
            System.err.println("Folder " + file.getParent() + " could not be created");
        }
        try {
            return new OutputStreamWriter(new FileOutputStream(file), charset);
        } catch (FileNotFoundException e) {
            throw new RuntimeException(e.getMessage(), e);
        }
    }
Export the given classes

@param classes classes to be scanned
querydsl-codegen/src/main/java/com/querydsl/codegen/GenericExporter.java