[Java] 日付文字列をDate型へ変換

DayUtil2.java

public static Date toDate(String value) throws ParseException {
  final String[] formats = {"yyyyMMdd", "yyyy/MM/dd", "yyyy-MM-dd"};
  ParseException parseEx = null;

  for (String format : formats) {
    try {
      return toDate(value, format);
    } catch (ParseException e) {
      parseEx = e;
      continue;
    }
  }

  throw parseEx;
}

private static Date toDate(String value, String format)
    throws ParseException {
  SimpleDateFormat formatter = new SimpleDateFormat(format);
  formatter.setLenient(false);
  return formatter.parse(value);
}

DayUtil2Test.java

@Test
public void testToDateYYYYMMDD() throws ParseException {
  assertEquals("Sun Jan 02 00:00:00 JST 2011", toDate("20110102").toString());
  assertEquals("Sun Jan 02 00:00:00 JST 2011", toDate("20110102a").toString());
  assertEquals("Sun Jan 02 00:00:00 JST 2011", toDate("2011012").toString());
}

@Test
public void testToDateSlash() throws ParseException {
  assertEquals("Sun Jan 02 00:00:00 JST 2011", toDate("2011/01/02").toString());
}

@Test
public void testToDateSlashNonZero() throws ParseException {
  assertEquals("Sun Jan 02 00:00:00 JST 2011", toDate("2011/1/2").toString());
  assertEquals("Sun Jan 02 00:00:00 JST 2011", toDate("2011/1/2a").toString());
}

@Test
public void testToDateHyphen() throws ParseException {
  assertEquals("Sun Jan 02 00:00:00 JST 2011", toDate("2011-01-02").toString());
}

@Test
public void testToDateHyphenNonZero() throws ParseException {
  assertEquals("Sun Jan 02 00:00:00 JST 2011", toDate("2011-1-2").toString());
}

@Test(expected=ParseException.class)
public void testToDateErrorChar() throws ParseException {
  toDate("abcd/ef/gh");
}

@Test(expected=ParseException.class)
public void testToDateErrorNotExists() throws ParseException {
  toDate("20110431");
}

@Test(expected=ParseException.class)
public void testToDateErrorLength() throws ParseException {
  toDate("201108310");
}

@Test(expected=ParseException.class)
public void testToDateErrorLengthDay() throws ParseException {
  toDate("2011/08/310");
}

@Test(expected=ParseException.class)
public void testToDateErrorLengthMonth() throws ParseException {
  toDate("2011-080-31");
}

@Test(expected=ParseException.class)
public void testToDateErrorNotDate() throws ParseException {
  toDate("20110100");
}

@Test
public void testToDateLeapYear() throws ParseException {
  assertEquals("Wed Feb 29 00:00:00 JST 2012", toDate("20120229").toString());
}

@Test(expected=ParseException.class)
public void testToDateErrorNotLeapYear() throws ParseException {
  toDate("20110229");
}