Java基于正则实现的日期校验功能示例

private void checkDate() throws IOException {    // 4种分隔符    String sep = "[-//./_]";    // 年份    String strPattern = "^(19[4-9]//d|20//d{2})" + sep;    strPattern += "(";    // 月（1,3,5,7,8,10,12)    strPattern += "((0?[13578]|1[02])" + sep + "(0?[1-9]|[12][0-9]|3[01]))|";    // 月(4,6,9,11)    strPattern += "((0?[469]|11)" + sep + "(0?[1-9]|[12][0-9]|30))|";    // 月（2）    strPattern += "((2)" + sep + "(0?[1-9]|[12]//d))";    strPattern += ")$";    Pattern p = Pattern.compile(strPattern);    Matcher m = p.matcher("");    int count = 0;    String fileName = ExcelGene.class.getResource("date.txt").getFile();    BufferedReader br = new BufferedReader(new FileReader(fileName));    String line = null;    while ((line = br.readLine()) != null) {      count++;      if (line.trim().length() > 0) {        m.reset(line);        if (!m.find()) {          System.out.println(count + " " + line);        } else {          String year = m.group(1);          String month = m.group(4);          month = month == null ? m.group(7) : month;          month = month == null ? m.group(10) : month;          String date = m.group(5);          date = date == null ? m.group(8) : date;          date = date == null ? m.group(11) : date;          System.out.println(year + "年" + month + "月" + date + "日");        }      }    }}