Question

我的数据库包含存储为文本字段的URL，每个URL包含报告日期的表示，报告本身缺少该表示。

所以我需要将URL字段中的日期解析为String表示，例如：

2010-10-12
2007-01-03
2008-02-07

提取日期的最佳方式是什么？

部分内容采用以下格式：

http://e.com/data/invoices/2010/09/invoices-report-wednesday-september-1st-2010.html

http://e.com/data/invoices/2010/09/invoices-report-thursday-september-2-2010.html

http://e.com/data/invoices/2010/09/invoices-report-wednesday-september-15-2010.html

http://e.com/data/invoices/2010/09/invoices-report-monday-september-13th-2010.html

http://e.com/data/invoices/2010/08/invoices-report-monday-august-30th-2010.html

http://e.com/data/invoices/2009/05/invoices-report-friday-may-8th-2009.html

http://e.com/data/invoices/2010/10/invoices-report-wednesday-october-6th-2010.html

http://e.com/data/invoices/2010/09/invoices-report-tuesday-september-21-2010.html

请注意，在这两个案例中，th日后的http://e.com/data/invoices/2010/09/invoices-report-wednesday-september-15-2010.html http://e.com/data/invoices/2010/09/invoices-report-monday-september-13th-2010.html使用不一致：

invoices-

其他人采用这种格式（在日期开始前有三个连字符，结尾没有年份，在report之前可选使用http://e.com/data/invoices/2010/09/invoices-report---wednesday-september-1.html http://e.com/data/invoices/2010/09/invoices-report---thursday-september-2.html http://e.com/data/invoices/2010/09/invoices-report---wednesday-september-15.html http://e.com/data/invoices/2010/09/invoices-report---monday-september-13.html http://e.com/data/invoices/2010/08/report---monday-august-30.html http://e.com/data/invoices/2009/05/report---friday-may-8.html http://e.com/data/invoices/2010/10/report---wednesday-october-6.html http://e.com/data/invoices/2010/09/report---tuesday-september-21.html）：

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Answer 1

你想要这样的正则表达式：

"^http://e.com/data/invoices/(\\d{4})/(\\d{2})/\\D+(\\d{1,2})"

这利用了URL的/年/月/部分之前的所有内容始终相同，并且直到该月的日期都没有数字。在你拥有它之后，你不关心任何其他事情。

第一个捕获组是年份，第二个月份，第三个捕获组。这一天可能没有前导零;根据需要从字符串转换为整数和格式，或者只是获取字符串长度，如果不是两个，则将其连接到字符串“0”。

举个例子：

import java.util.regex.*;

class URLDate {
  public static void
  main(String[] args) {
    String text = "http://e.com/data/invoices/2010/09/invoices-report-wednesday-september-1st-2010.html";
    String regex = "http://e.com/data/invoices/(\\d{4})/(\\d{2})/\\D+(\\d{1,2})";
    Pattern p = Pattern.compile(regex);
    Matcher m = p.matcher(text);
    if (m.find()) {
      int count = m.groupCount();
      System.out.format("matched with groups:\n", count);
      for (int i = 0; i <= count; ++i) {
          String group = m.group(i);
          System.out.format("\t%d: %s\n", i, group);
      }
    } else {
      System.out.println("failed to match!");
    }
  }
}

给出输出：

matched with groups:
    0: http://e.com/data/invoices/2010/09/invoices-report-wednesday-september-1st-2010.html
    1: 2010
    2: 09
    3: 1

（请注意，要使用Matcher.matches()代替Matcher.find()，您必须通过将.*$附加到模式来使模式占用整个输入字符串。）

如何从URL格式解析日期？

1 个答案: