Java中时间处理（util.Date，sql.Date / sql.TimeStamp，LocalDate / LocalDateTime）

1 util.Date -> Long类型时间戳

 System.out.println(new Date());  // Thu Jul 14 14:53:40 CST 2022
 System.out.println(new Date().getTime());  // 1657781804545

2 Long类型时间戳 -> sql.Date / TimeStamp

System.out.println(new java.sql.Date(new Date().getTime()));   // 2022-07-14
System.out.println(new java.sql.Timestamp(new Date().getTime()));  // 2022-07-14 14:58:22.067

3 sql.Date / TimeStamp -> LocalDate / LocalDateTime

LocalDateTime localDateTime1 = Timestamp.valueOf(LocalDateTime.now()).toLocalDateTime();
LocalDate localDate = java.sql.Date.valueOf(LocalDate.now()).toLocalDate();

4 String -> LocalDate / LocalDateTime

String s1 = "2022-07-14 15:06:00";
DateTimeFormatter formatter1 = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
System.out.println(LocalDateTime.from(formatter1.parse(s1)));   // 2022-07-14T15:06

String s2 = "2022-07-14";
DateTimeFormatter formatter2 = DateTimeFormatter.ofPattern("yyyy-MM-dd");
System.out.println(LocalDate.from(formatter2.parse(s2)));   // 2022-07-14

5 LocalDate / LocalDateTime -> sql.Date / TimeStamp

System.out.println(java.sql.Date.valueOf(LocalDate.now()));  // 2022-07-14
System.out.println(java.sql.Timestamp.valueOf(LocalDateTime.now()));  // 2022-07-14 15:03:54.624

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