java - simpleDateformat 解析の問題

Question

Timestamp tsmp = Timestamp.valueOf("0302-02-20 00:00:00");
final DateFormat df = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
System.out.println(df.format(tsmp));

このコード セグメントは次のように出力します: 0302-02-20 12:00:00 なぜですか? 誰でも説明できますか？

Answer 1

You're using hh, which is 12-hour format ("Hour in am/pm (1-12)" as specified in the docs). Use HH instead.

final DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

You should pretty much never use hh unless you're also using a, the AM/PM designator.

(Did you really mean to create a timestamp in the year 302AD though, out of interest?)

Answer 2

new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");

Read the API again. The time symbols are not all lower case characters.

Answer 3

DateFormat df = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");