org.supercsv.cellprocessor.ConvertNullTo Java Examples

public static <V> void writeCsv(final DataFrame<V> df, final OutputStream output)
throws IOException {
    try (CsvListWriter writer = new CsvListWriter(new OutputStreamWriter(output), CsvPreference.STANDARD_PREFERENCE)) {
        final String[] header = new String[df.size()];
        final Iterator<Object> it = df.columns().iterator();
        for (int c = 0; c < df.size(); c++) {
            header[c] = String.valueOf(it.hasNext() ? it.next() : c);
        }
        writer.writeHeader(header);
        final CellProcessor[] procs = new CellProcessor[df.size()];
        final List<Class<?>> types = df.types();
        for (int c = 0; c < df.size(); c++) {
            final Class<?> cls = types.get(c);
            if (Date.class.isAssignableFrom(cls)) {
                procs[c] = new ConvertNullTo("", new FmtDate("yyyy-MM-dd'T'HH:mm:ssXXX"));
            } else {
                procs[c] = new ConvertNullTo("");
            }
        }
        for (final List<V> row : df) {
            writer.write(row, procs);
        }
    }
}
 

/**
 * An example of partial reading using CsvDozerBeanWriter.
 */
private static void partialWriteWithCsvDozerBeanWriter() throws Exception {
	// ignore questionNo/answer 1 columns
	final String[] partialFieldMapping = new String[] {
			"age",
			"consentGiven",
			"answers[1].questionNo",
			"answers[1].answer",
			"answers[2].questionNo",
			"answers[2].answer" };
	
	// ignore questionNo/answer 1 columns keep up with partialFieldMapping
	final CellProcessor[] partialProcessors = new CellProcessor[] { 
		new Token(0, "age not supplied"), // age
		new FmtBool("Y", "N"),                 // consent
		new NotNull(),                         // questionNo 2
		new ConvertNullTo("not answered"),     // answer 2
		new NotNull(),                         // questionNo 3
		new ConvertNullTo("not answered")};    // answer 3
	
	// create the survey responses to write
	SurveyResponse response1 = new SurveyResponse(18, true, Arrays.asList(new Answer(1, "Twelve"), new Answer(2,
		"Albert Einstein"), new Answer(3, "Big Bang Theory")));
	SurveyResponse response2 = new SurveyResponse(0, true, Arrays.asList(new Answer(1, "Thirteen"), new Answer(2,
		"Nikola Tesla"), new Answer(3, "Stargate")));
	SurveyResponse response3 = new SurveyResponse(42, false, Arrays.asList(new Answer(1, null), new Answer(2,
		"Carl Sagan"), new Answer(3, "Star Wars")));
	final List<SurveyResponse> surveyResponses = Arrays.asList(response1, response2, response3);
	
	ICsvDozerBeanWriter beanWriter = null;
	try {
		beanWriter = new CsvDozerBeanWriter(new FileWriter("target/partialWriteWithCsvDozerBeanWriter.csv"),
			CsvPreference.STANDARD_PREFERENCE);
		
		// configure the mapping from the fields to the CSV columns
		beanWriter.configureBeanMapping(SurveyResponse.class, partialFieldMapping);
		
		// write the header
		beanWriter.writeHeader("age", "consentGiven", "questionNo2", "answer2",
			"questionNo3", "answer3");
		
		// write the beans
		for( final SurveyResponse surveyResponse : surveyResponses ) {
			beanWriter.write(surveyResponse, partialProcessors);
		}
		
	}
	finally {
		if( beanWriter != null ) {
			beanWriter.close();
		}
	}
}