Date.plus not working in 2.5.4 Groovy Runtime, what is the alternative?

问题

We want to add days to the current date and format it in a specific way. This was solved in Groovy 2.4.13 and the following date manipulation works fine:

today = new Date()+90;today.format('yyyy-MM-dd HH:mm:ss.S');

Result: 2019-12-02 08:07:15.294

In Groovy 2.5.4 the same expression throws this exception:

groovy.lang.MissingMethodException: No signature of method: java.util.Date.plus() is applicable for argument types: (Integer) values: [90] Possible solutions: parse(java.lang.String), split(groovy.lang.Closure), use([Ljava.lang.Object;), is(java.lang.Object), wait(), clone() at Script1.run(Script1.groovy:3)

I was able to reproduce this behaviour in "Groovy sandboxes" online:

Working fine here: groovy-playground (Version 2.4.1.5) Failing here: groovyconsole (Version 2.5.7)

What is the working alternative in this case? I have read about a new Date API, but couldn't find the details about how to use it, with date manipulation (+ 90 days for example).

回答1:

I agree with Ole V.V.'s recommendations to use the new Date/Time API. Here is how you would write his Java sample in a more Groovy style.

// you can assemble aggregate types by left shifting the aggregates
// I'm not endorsing this approach, necessarily, just pointing it out as an alternative 
ZonedDateTime now = LocalDate.now() << LocalTime.now() << ZoneId.of('Africa/Bamako')

// the plus operator is overloaded
ZonedDateTime in90Days = now + 90

// you can pass a String to format without needed a full DateTimeFormatter instance
println in90Days.format('uuuu-MM-dd HH:mm:ss.S')

回答2:

While Groovy adds some further support for the old Java Date class, I still believe that you should not use it. It was always poorly designed and is now long outdated. Instead use java.time, the modern Java date and time API. I am sorry that I will have to trust you to translate from Java code.

    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss.S");
    ZonedDateTime now = ZonedDateTime.now(ZoneId.of("Africa/Bamako"));
    ZonedDateTime in90Days = now.plusDays(90);
    System.out.println(in90Days.format(formatter));

Output when running just now was:

2020-01-01 08:37:13.3

Please substitute your desired time zone if it didn’t happen to be Africa/Bamako.

Link: Oracle tutorial: Date Time explaining how to use java.time.

回答3:

Take a look at TimeCategory

import groovy.time.TimeCategory
def theDate = use(TimeCategory){new Date() + 90.days}.format('yyyy-MM-dd HH:mm:ss.S')

回答4:

You can use Calendar to achieve that

    Calendar cal = new GregorianCalendar();
    cal.add(Calendar.DATE, 90);
    Date date = cal.getTime();

All steps must be separate and not in a single line.

来源：https://stackoverflow.com/questions/58214893/date-plus-not-working-in-2-5-4-groovy-runtime-what-is-the-alternative

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java

date

groovy