tl;dr
LocalDate.parse(
"January 08, 2017" ,
DateTimeFormatter.ofPattern( "MMMM dd, uuuu" , Locale.US )
).format( DateTimeFormatter.BASIC_ISO_DATE )
Using java.time
The Question and other Answers use troublesome old date-time classes, now legacy, supplanted by the java.time classes.
You have date-only values, so use a date-only class. The LocalDate
class represents a date-only value without time-of-day and without time zone.
String input = "January 08, 2017";
Locale l = Locale.US ;
DateTimeFormatter f = DateTimeFormatter.ofPattern( "MMMM dd, uuuu" , l );
LocalDate ld = LocalDate.parse( input , f );
Your desired output format is defined by the ISO 8601 standard. For a date-only value, the “expanded” format is YYYY-MM-DD such as 2017-01-08
and the “basic” format that minimizes the use of delimiters is YYYYMMDD such as 20170108
.
I strongly suggest using the expanded format for readability. But if you insist on the basic format, that formatter is predefined as a constant on the DateTimeFormatter
class named BASIC_ISO_DATE
.
String output = ld.format( DateTimeFormatter.BASIC_ISO_DATE );
See this code run live at IdeOne.com.
ld.toString(): 2017-01-08
output: 20170108
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
.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
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. Hibernate 5 & JPA 2.2 support java.time.
Where to obtain the java.time classes?