史上最全java日期转换

史上最全java日期转换

使用jodaTime，满足各种转化姿势

依赖

引入jodaTime依赖

<dependency>
    <groupId>joda-timegroupId>
    <artifactId>joda-timeartifactId>
    <version>2.9.9version>
dependency>

Mysql日期和时间

mysql类型	对应java类型	日期或时间格式	日期或时间范围	默认值	占用空间
YEAR	java.sql.Date	YYYY	1901 ~ 2155	0000	1 bytes
TIME	java.sql.Time	HH:MM:SS	-838:59:59 ~ 838:59:59	00:00:00	3 bytes
DATE	java.sql.Date	YYYY-MM-DD	1000-01-01 ~ 9999-12-3	0000-00-00	4 bytes
TIMESTAMP	java.sql.Timestamp	YYYY-MM-DD HH:MM:SS	1970-01-01 00:00:01 UTC ~ 2038-01-19 03:14:07 UTC	00000000000000	4 bytes
DATETIME	java.sql.Timestamp	YYYY-MM-DD HH:MM:SS	1000-01-01 00:00:00 ~ 9999-12-31 23:59:59	0000-00-00 00:00:00	8 bytes

列举这个表格，是为了快速查找对应类型，方便我们建立java语言与SQL语言的连接通道。

转换

时间类型转化的场景很多，下面我举几个例子,基本解决了大多数场景，希望大家能举一反三

1. yyyy-MM-dd 转 java.sql.Date

String fmtPattern = "yyyy-MM-dd";
DateTimeFormatter fmt = DateTimeFormat.forPattern(fmtPattern);
DateTime dateTime = fmt.parseDateTime("2020-08-10");
java.sql.Date date = new java.sql.Date(dateTime.getMillis());
System.out.println(date.toString()); // 2020-08-10

2. YYYY-MM-DD HH:MM:SS 转 java.util.Date

   String fmtPattern = "yyyy-MM-dd HH:mm:ss";
   DateTimeFormatter fmt = DateTimeFormat.forPattern(fmtPattern);
   DateTime dateTime = fmt.parseDateTime("2020-08-10 10:30:20");
   java.util.Date date = new java.util.Date(dateTime.getMillis());
   System.out.println(date.toString()); // Mon Aug 10 10:30:20 CST 2020
   

3. YYYY-MM-DD HH:MM:SS 转 java.util.Timestamp

String fmtPattern = "yyyy-MM-dd HH:mm:ss";
DateTimeFormatter fmt = DateTimeFormat.forPattern(fmtPattern);
DateTime dateTime = fmt.parseDateTime("2020-08-10 10:30:20");
java.sql.Timestamp timestamp = new Timestamp(dateTime.getMillis());
System.out.println(timestamp.toString()); // 2020-08-10 10:30:20.0
System.out.println(timestamp.getTime()); // 1597026620000

4. HH:MM:SS 转 java.sql.Time

   String fmtInput = "HH:mm:ss";
   DateTimeFormatter fmt = DateTimeFormat.forPattern(fmtInput);
   DateTime dateTime = fmt.parseDateTime("11:30:20");
   Time time = new Time(dateTime.toDate().getTime());
   System.out.println(time.toString()); // 11:30:20
   

5. YYYY 转 java.sql.Date

   String fmtPattern = "yyyy";
   DateTimeFormatter fmt = DateTimeFormat.forPattern(fmtPattern);
   DateTime dateTime = fmt.parseDateTime("2020");
   java.sql.Date date = new Date(dateTime.getMillis());
   System.out.println(date.toString()); // 2020-01-01