使用 Univocity 处理“”、“-”CSV

Question

知道如何获得正确的台词吗？有些线粘在一起了，我不知道如何停止它或为什么。

  col. 0: Date
  col. 1: Col2
  col. 2: Col3
  col. 3: Col4
  col. 4: Col5
  col. 5: Col6
  col. 6: Col7
  col. 7: Col7
  col. 8: Col8

  col. 0: 2017-05-23
  col. 1: String
  col. 2: lo rem ipsum
  col. 3: dolor sit amet
  col. 4: mcdonalds.com/online.html
  col. 5: null
  col. 6: "","-""-""2017-05-23"
  col. 7: String
  col. 8: lo rem ipsum
  col. 9: dolor sit amet
  col. 10: burgerking.com
  col. 11: https://burgerking.com/
  col. 12: 20
  col. 13: 2
  col. 14: fake

  col. 0: 2017-05-23
  col. 1: String
  col. 2: lo rem ipsum
  col. 3: dolor sit amet
  col. 4: wendys.com
  col. 5: null
  col. 6: "","-""-""2017-05-23"
  col. 7: String
  col. 8: lo rem ipsum
  col. 9: dolor sit amet
  col. 10: buggagump.com
  col. 11: null
  col. 12: "","-""-""2017-05-23"
  col. 13: String
  col. 14: cheese
  col. 15: ad eum
  col. 16: mcdonalds.com/online.html
  col. 17: null
  col. 18: "","-""-""2017-05-23"
  col. 19: String
  col. 20: burger
  col. 21: ludus dissentiet
  col. 22: www.mcdonalds.com
  col. 23: https://www.mcdonalds.com/
  col. 24: 25
  col. 25: 3
  col. 26: fake

  col. 0: 2017-05-23
  col. 1: String
  col. 2: wine
  col. 3: id erat utamur
  col. 4: bubbagump.com
  col. 5: https://buggagump.com/
  col. 6: 25
  col. 7: 3
  col. 8: fake
  done

CSV 示例（\r\n 在 copy/pasting 时可能已损坏）。此处可用：https://www.dropbox.com/s/86klza4qok4ty2s/malformed%20csv%20r%20n%20small.csv?dl=0

"Date","Col2","Col3","Col4","Col5","Col6","Col7","Col7","Col8"
"2017-05-23","String","lo rem ipsum","dolor sit amet","mcdonalds.com/online.html","","-","-","-"
"2017-05-23","String","lo rem ipsum","dolor sit amet","burgerking.com","https://burgerking.com/","20","2","fake"
"2017-05-23","String","lo rem ipsum","dolor sit amet","wendys.com","","-","-","-"
"2017-05-23","String","lo rem ipsum","dolor sit amet","buggagump.com","","-","-","-"
"2017-05-23","String","cheese","ad eum","mcdonalds.com/online.html","","-","-","-"
"2017-05-23","String","burger","ludus dissentiet","www.mcdonalds.com","https://www.mcdonalds.com/","25","3","fake"
"2017-05-23","String","wine","id erat utamur","bubbagump.com","https://buggagump.com/","25","3","fake"

建筑设置：

  CsvParserSettings settings = new CsvParserSettings();

  settings.setDelimiterDetectionEnabled(true);
  settings.setQuoteDetectionEnabled(true);

  settings.setLineSeparatorDetectionEnabled(false); // all the same using `true`
  settings.getFormat().setLineSeparator("\r\n");

  CsvParser parser = new CsvParser(settings);

  List<String[]> rows;

  rows = parser.parseAll(getReader("testFiles/" + "malformed csv small.csv"));

  for (String[] row : rows)
  {
    System.out.println("");
    int i = 0;

    for (String element : row)
    {
      System.out.println("col. " + i++ + ": " + element);
    }
  }

  System.out.println("done");

Answer 1

由于您正在测试自动检测过程，我建议您打印出检测到的格式：

CsvFormat format = parser.getDetectedFormat();
System.out.println(format);

这将打印出：

CsvFormat:
    Comment character=#
    Field delimiter=,
    Line separator (normalized)=\n
    Line separator sequence=\r\n
    Quote character="
    Quote escape character=-
    Quote escape escape character=null

如您所见，解析器未正确检测引号转义。虽然格式检测过程通常非常好，但不能保证它总是正确的，特别是对于小测试样本。在您的样本中，我不明白为什么它会选择 - 作为转义字符，所以我打开这个 issue 来调查并查看是什么让它检测到那个字符。

如果您知道输入文件中的 none 永远不会有 - 作为引号转义，您现在可以做的解决方法是检测格式，测试它从输入中获取的内容，然后解析内容，如下所示：

public List<String[]> parse(File input, CsvFormat format) {
    CsvParserSettings settings = new CsvParserSettings();
    if (format == null) { //no format specified? Let's detect what we are dealing with
        settings.detectFormatAutomatically();

        CsvParser parser = new CsvParser(settings);
        parser.beginParsing(input); //just call begin parsing to kick of the auto-detection process
        format = parser.getDetectedFormat(); //capture the format
        parser.stopParsing(); //stop the parser - no need to read anything yet.

        System.out.println(format);

        if (format.getQuoteEscape() == '-') { //got something weird detected? Let's amend it.
            format.setQuoteEscape('"');
        }

        return parse(input, format); //now parse with the intended format
    } else {
        settings.setFormat(format); //this parses with the format adjusted earlier.
        CsvParser parser = new CsvParser(settings);
        return parser.parseAll(input);
    }

}

现在只需调用 parse 方法：

List<String[]> rows = parse(new File("/Users/jbax/Downloads/malformed csv r n small.csv"), null);

您将正确提取数据。希望这对您有所帮助！

使用 Univocity 处理“”、“-”CSV

Handling "", "-" CSV with Univocity

java

csv

parsing

univocity