code: public void write(String[] dataLine, char dataSeparator) {
          if (dataLine == null || dataLine.length == 0) {
              return;
          }
          stringBuffer.setLength(0);
          for (String line : dataLine) {
              stringBuffer.append(line);
              stringBuffer.append(dataSeparator);
          }
          stringBuffer.append(lineSeparator);
          stringBuffer.deleteCharAt(stringBuffer.length() - 2);
          fileAppendWriter.write(stringBuffer.toString());
      }
docs: 写入每行数据
  
  @param dataLine 每个字段的值
  @param dataSeparator 字段之间的分隔符
  @throws IOException