如何在grails域中捕获毫秒

Question

I have a grails domain that stores data in MySQL.

In it I have a Date property which creates a DateTime field in the DB. However, I also wish to capture the milliseconds in addition to the date.

Is there a way to capture milliseconds?

Example:

Class MyClass {

  Date dateCreated

}

stores data in MySQL as 2014-10-06 16:21:57 but I'd like to capture milliseconds as well.

Answer 1

MySQL 5.6.4 and up can save milliseconds in the database for datetime objects by defining the amount of fractional points for the object. (Read more here: MySQL reference manual ). By default Grails/Gorm doesn't do this. Fortunately, this is easily solved by defining a sqlType in the domain like this:

class ExampleDomain {
    Date date

    static mapping = {
        date sqlType: 'datetime(3)'
    }
}

Answer 2

You could use bigint(20). Your groovy/grails domain could look like that if you want to store the nanoseconds since unix epoch automatically when a instance will be saved:

class myClass {

  Integer id
  Long timestamp = System.nanoTime()

  static mapping = {
    timestamp sqlType: "bigint"
  }
}