Groovy String to Date
StringParsingDateGroovyString Problem Overview
I am coding this with Groovy
I am currently trying to convert a string that I have to a date without having to do anything too tedious.
String theDate = "28/09/2010 16:02:43";
def newdate = new Date().parse("d/M/yyyy H:m:s", theDate)
Output:
Tue Aug 10 16:02:43 PST 2010
The above code works just fine, however when my string changes to something like:
String testDate = "Tue Aug 10 16:02:43 PST 2010"
def newerdate = new Date().parse("d/M/yyyy H:m:s", testDate)
It tells me that "there is no such value for Tue". I tried to throw an 'E' in the parse for the date but it said the date was not able to be parsed.
Can someone explain how I should go about parsing the second example?
String Solutions
Solution 1 - String
The first argument to parse() is the expected format. You have to change that to Date.parse("E MMM dd H:m:s z yyyy", testDate)
for it to work. (Note you don't need to create a new Date object, it's a static method)
If you don't know in advance what format, you'll have to find a special parsing library for that. In Ruby there's a library called Chronic, but I'm not aware of a Groovy equivalent. Edit: There is a Java port of the library called jChronic, you might want to check it out.
Solution 2 - String
Try this:
def date = Date.parse("E MMM dd H:m:s z yyyy", dateStr)
Here are the patterns to format the dates
Solution 3 - String
JChronic is your best choice. Here's an example that adds a .fromString()
method to the Date class that parses just about anything you can throw at it:
Date.metaClass.'static'.fromString = { str ->
com.mdimension.jchronic.Chronic.parse(str).beginCalendar.time
}
You can call it like this:
println Date.fromString("Tue Aug 10 16:02:43 PST 2010")
println Date.fromString("july 1, 2012")
println Date.fromString("next tuesday")
Solution 4 - String
Date#parse
is deprecated . The alternative is :
java.text.DateFormat#parse
thereFore :
new SimpleDateFormat("E MMM dd H:m:s z yyyy", Locale.ARABIC).parse(testDate)
###Note that SimpleDateFormat is an implementation of DateFormat
Solution 5 - String
Googling around for Groovy ways to "cast" a String
to a Date
, I came across this article:
http://www.goodercode.com/wp/intercept-method-calls-groovy-type-conversion/
The author uses Groovy metaMethods to allow dynamically extending the behavior of any class' asType
method. Here is the code from the website.
class Convert {
private from
private to
private Convert(clazz) { from = clazz }
static def from(clazz) {
new Convert(clazz)
}
def to(clazz) {
to = clazz
return this
}
def using(closure) {
def originalAsType = from.metaClass.getMetaMethod('asType', [] as Class[])
from.metaClass.asType = { Class clazz ->
if( clazz == to ) {
closure.setProperty('value', delegate)
closure(delegate)
} else {
originalAsType.doMethodInvoke(delegate, clazz)
}
}
}
}
They provide a Convert
class that wraps the Groovy complexity, making it trivial to add custom as
-based type conversion from any type to any other:
Convert.from( String ).to( Date ).using { new java.text.SimpleDateFormat('MM-dd-yyyy').parse(value) }
def christmas = '12-25-2010' as Date
It's a convenient and powerful solution, but I wouldn't recommend it to someone who isn't familiar with the tradeoffs and pitfalls of tinkering with metaClasses.
Solution 6 - String
I think the best easy way in this case is to use http://docs.groovy-lang.org/2.4.3/html/groovy-jdk/java/util/Date.html#parseToStringDate(java.lang.String)">parseToStringDate</a> which is part of GDK (Groovy JDK enhancements):
> Parse a String matching the pattern EEE MMM dd HH:mm:ss zzz yyyy > containing US-locale-constants only (e.g. Sat for Saturdays). Such a > string is generated by the toString method of Date
Example:
println(Date.parseToStringDate("Tue Aug 10 16:02:43 PST 2010").format('MM-dd-yyyy'))
Solution 7 - String
Below is the way we are going within our developing application.
import java.text.SimpleDateFormat
String newDateAdded = "2018-11-11T09:30:31"
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss")
Date dateAdded = dateFormat.parse(newDateAdded)
println(dateAdded)
The output looks like
Sun Nov 11 09:30:31 GMT 2018
In your example, we could adjust a bit to meet your need. If I were you, I will do:
String datePattern = "d/M/yyyy H:m:s"
String theDate = "28/09/2010 16:02:43"
SimpleDateFormat df = new SimpleDateFormat(datePattern)
println df.parse(theDate)
I hope this would help you much.