Java : Date String to Hours

Question

i have this Date String 2020-07-26T20:08:27Z i want to perform date comparison.

so is there any framework/util for this operation.

String s1 = "2020-07-26T20:08:27Z";
String s2 = "2020-07-26T21:08:27Z";

in the above sample code, i want to find the bigger date

Answer 1

tl;dr

Instant
.parse( "2020-07-26T20:08:27Z" ) 
.isBefore(
    Instant.parse( "2020-07-26T21:08:27Z" )
)

true

java.time

Use the modern java.time classes built into Java 8 and later.

ISO 8601

The Z on the end of your input indicates an offset-from-UTC of zero hours-minutes-seconds, or UTC itself. The Z is pronounced “Zulu”.

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

Instant

An Instant object represents a moment in UTC.

Instant instantA = Instant.parse( "2020-07-26T20:08:27Z" ) ;
Instant instantB = Instant.parse( "2020-07-26T21:08:27Z" ) ;

Compare using equals, isBefore, isAfter.

boolean aBeforeB = instantA.isBefore( instantB ) ;

Duration

You can capture the time elapsed between the two moments as a Duration object.

Duration d = Duration.between( instantA , instantB ) ;

You can ask the Duration object if it is zero or negative.

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Answer 2

For this use compareTo() Method. I Have an example for you

      SimpleDateFormat sdformat = new SimpleDateFormat("yyyy-MM-dd");
  Date d1 = sdformat.parse("2019-04-15");
  Date d2 = sdformat.parse("2019-08-10");
  System.out.println("The date 1 is: " + sdformat.format(d1));
  System.out.println("The date 2 is: " + sdformat.format(d2));
  if(d1.compareTo(d2) > 0) {
     System.out.println("Date 1 occurs after Date 2");
  } else if(d1.compareTo(d2) < 0) {
     System.out.println("Date 1 occurs before Date 2");
  } else if(d1.compareTo(d2) == 0) {
     System.out.println("Both dates are equal");
  }