DataFrameWriter { public void csv(String file) throws IOException { CsvWriteOptions options = CsvWriteOptions.builder(file).build(); new CsvWriter().write(table, options); } DataFrameWriter(WriterRegistry registry, Table table); void toFile(String file); void toFile(File file); void toStream(OutputStream stream, String extension); void toWriter(Writer writer, String extension); void usingOptions(T options); String toString(String extension); void csv(String file); void csv(File file); void csv(CsvWriteOptions options); void csv(OutputStream stream); void csv(Writer writer);  }
@Test public void csv() { ByteArrayOutputStream baos = new ByteArrayOutputStream(); table.write().csv(baos); String output = baos.toString(); assertEquals( "v,v2" + LINE_END + "1.0,1.0" + LINE_END + "2.0,2.0" + LINE_END + "," + LINE_END + "", output); }