public void exportData() throws IOException {

    FacesContext facesContext = FacesContext.getCurrentInstance();
    ExternalContext externalContext = facesContext.getExternalContext();
    externalContext.setResponseContentType("text/csv");
    externalContext.setResponseHeader("Content-Disposition", "attachment; filename="all_files.csv"");

    OutputStream out = externalContext.getResponseOutputStream();
    Writer writer = new OutputStreamWriter(out);

    String sql = "SELECT"
            + "     job_class_cd "JOB CLASS","
            + "     pay_grade "PAY GRADE","
            + "     job_class_title,"
            + "     mou,"
            + "     mou_description,"
            + "     nvl(REGEXP_REPLACE(minimum_annual, '\.[0-9]*', ''), ' ') "MINIMUM ANNUAL","
            + "     nvl(REGEXP_REPLACE(maximum_annual, '\.[0-9]*', ''), ' ') "MAXIMUM ANNUAL","
            + "     nvl(salary_range || CASE WHEN min_step IS NULL THEN '' ELSE ' ('  || to_char(MIN_STEP) || ')' END, ' ') "SALARY RANGE (MIN STEP)","
            + "     nvl(rate_type, ' ') "RATE TYPE","
            + "     nvl(flat_rate, ' ') "FLAT RATE","
            + "     nvl(per_event_rate, ' ') "PER EVENT RATE","
            + "     step_1,"
            + "     step_2,"
            + "     step_3,"
            + "     step_4,"
            + "     step_5,"
            + "     step_6,"
            + "     step_7,"
            + "     step_8,"
            + "     step_9,"
            + "     step_10,"
            + "     step_11,"
            + "     step_12,"
            + "     step_13,"
            + "     step_14,"
            + "     step_15"
            + " FROM myApp.st_s_spay"
            + "       ORDER BY job_class_title, job_class_cd, pay_grade, rate_type desc";

    // MARK: CSV content header
    try {

        writer.write("JOB CLASS,PAY GRADE,JOB_CLASS_TITLE");
        writer.write("PAY GRADE, JOB_CLASS_TITLE");
        writer.write(", MOU,MOU_DESCRIPTION");
        writer.write(", MINIMUM ANNUAL,MAXIMUM ANNUAL");
        writer.write(", SALARY RANGE, RATE TYPE");
        writer.write(", FLAT RATE, PER EVENT RATE");
        writer.write(",STEP_1, STEP_2");
        writer.write(",STEP_3, STEP_4");
        writer.write(",STEP_5, STEP_6");
        writer.write(",STEP_7, STEP_8");
        writer.write(",STEP_9, STEP_10");
        writer.write(",STEP_11, STEP_12");
        writer.write(",STEP_13, STEP_14");
        writer.write(",STEP_15");

    } finally {
        if (writer != null) {

            // MARK: Close and flush the  OutputStream
            writer.close();
        }
    }

    facesContext.responseComplete();
}