如何将Joda DateTime转换为UTC MySql时间戳

Question

I have a Joda DateTime object representing a UTC time, and wish to store it in a Timestamp field in a MySql table.

I have the following code:

String ztime = "2013-10-07T08:00:00Z";  

DateTimeFormatter parser = ISODateTimeFormat.dateTimeParser();
DateTime dt = parser.parseDateTime(ztime).withZone(DateTimeZone.UTC);

PreparedStatement stmt = con.prepareStatement("insert into time_test (time) values (?)");
stmt.setTimestamp(1, Timestamp(dt.getMillis()));
stmt.execute();

However, when I look in the database, the time that gets store is out by the difference of my database's timezone from UTC. eg when my database is running in UTC+1, and run the above code to save "08:00Z", in the database the Timestamp shows as 09:00.

DateTime's getMillis method says " Gets the milliseconds of the datetime instant from the Java epoch of 1970-01-01T00:00:00Z." and MySql's Timestamp says: "MySQL converts TIMESTAMP values from the current time zone to UTC for storage, and back from UTC to the current time zone for retrieval.", so I presume it's the MySql conversion that's causing the issue, because the millis it's being initialized with is relative to a fixed UTC time, so it has no need to convert from current time zone to UTC.

My code to read the data back out into a DateTime works fine, and I get the value out that I put in, but I also need this to work with some 3rd-party code over which I have no control, which expects the Timestamp to be in the correct UTC time.

How do I get the Timestamp field in the database to match my original UTC date/time ?

Answer 1

tl;dr

Use java.time classes that supplant Joda-Time .

myPreparedStatement.setObject( 
    … , 
    Instant.parse( "2013-10-07T08:00:00Z" )  
)

Retrieve.

myResultSet.getObject( 
    … ,
    Instant.class 
)

java.time

The Joda-Time project is now in maintenance-mode, recommending migration to its successor, the java.time classes built into Java 8 and later. Both are led by the same man, Stephen Colebourne. You'll find many of the same concepts in play, so fairly easy to migrate.

The Instant class represents a moment on the timeline in UTC with a resolution of nanoseconds (up to nine (9) digits of a decimal fraction).

Your input string happens to be in standard ISO 8601 format. The java.time classes use these standard formats by default when parsing/generating strings. So no need to specify a formatting pattern.

String input = "2013-10-07T08:00:00Z" ;     // Standard ISO 8601 format.
Instant instant = Instant.parse( input ) ;  // Parses standard ISO 8601 format by default.

The Instant class replaces both java.util.Date and java.sql.Timestamp . As of JDBC 4.2 and later, you can directly exchange java.time objects with the database.

myPreparedStatement.setObject( … , instant ) ;

And retrieval.

Instant instant = myResultSet.getObject( … , Instant.class ) ;

The TIMESTAMP type in MySQL seems to be akin to the SQL-standard TIMESTAMP WITH TIME ZONE type. So the code above should work appropriately.

---

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date , Calendar , & SimpleDateFormat .

The Joda-Time project, now in maintenance mode , advises migration to the java.time classes.

To learn more, see the Oracle Tutorial . And search Stack Overflow for many examples and explanations. Specification is JSR 310 .

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

Where to obtain the java.time classes?

• Java SE 8 , Java SE 9 , Java SE 10 , and later
  • Built-in.
  • Part of the standard Java API with a bundled implementation.
  • Java 9 adds some minor features and fixes.
• Java SE 6 and Java SE 7
  • Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport .
• Android
  • Later versions of Android bundle implementations of the java.time classes.
  • For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP… .

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval , YearWeek , YearQuarter , and more .