JIYIK CN >

There are various options available for converting date string to date format. The methods mentioned below can bring the desired result. Let us understand the various ways from the following code block.

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.Locale;

public class StringToDateFormat {
  public static void main(String[] args) throws ParseException {
    System.out.print("Way1: ");
    SimpleDateFormat dt = new SimpleDateFormat("yyyyy-MM-dd");
    System.out.print(dt.parse("2021-11-05") + "\n");

    System.out.print("Way2: ");
    SimpleDateFormat formatter = new SimpleDateFormat("dd/MMM/yyyy HH:mm:ss", Locale.ENGLISH);
    System.out.print(formatter.parse("21/JAN/2021 21:35:56") + "\n");

    System.out.print("Way3: ");
    DateTimeFormatter formatter1 = DateTimeFormatter.ofPattern("EEE, d MMM yyyy", Locale.ENGLISH);
    System.out.print(LocalDate.parse("Wed, 5 May 2021", formatter1) + "\n");

    System.out.print("Way4: ");
    System.out.print(LocalDate.parse("2021-05-31") + "\n");
  }
}

In Way1, an instance of the class is created SimpleDateFormat. It takes a value in the format of the input date string pattern. So, in this way, we input yyyy-MM-ddthe date in the format of . The instantiation also throws some exceptions like NullPointerExceptionand if the parameter is null or illegal IllegalArgumentException. Now using the recently created formatterobject, we initialize a parsemethod. This method takes the date string as input value and returns the data type after parsing 日期. It throws when the given date string and the formatter do not match, or when the internal date string is not parsed ParseException.

In Way2, SimpleDateFormatthe class is used again to create the format that should be entered. But now, the overridden SimpleDateFormatconstructor of is called. The first parameter is Datea string format/pattern. The other is a string that defines a specific geographic region or area Locale. Note:All locales are not allowed in the method. Now, check dd/MMM/yyyy HH:mm: ssthe pattern that displays the month in mmm format. The format implies that the shorthand form of the month is acceptable in mmm form. In addition, the format string may require hours, minutes, and seconds.

In Way3, use DateTimeFormatthe formatter class to format and print date time objects. ofPatternThe formatter method is used to prepare the formatter for the required pattern. Now call LocalDatethe static methods of the formatter class to parse the date. The method is parseused to parse the text and DateTimeFormatteris used to specify the format of the input date text. The method returns LocalDatea datetime instance and is not null. It throws when the text cannot be parsed DateTimeParseException. The format can also take a day name. EEEThe abbreviations represent the same in the formatter.

In Way4, the method, which is LocalDatea static factory method of the class , is called directly parse. This time, no formatter instance or pattern is defined in any way. Now the function takes yyyy-MM-ddan input date string of the form . The specified date string must always represent a valid date and DateTimeFormatter.ISO_LOCAL_DATEbe converted using the format. The method throws an exception when the text cannot be parsed DateTimeParseException.

Below is the output of the code that converts the date string Dateinto .

Way1: Fri Nov 05 00:00:00 IST 2021
Way2: Thu Jan 21 21:35:56 IST 2021
Way3: 2021-05-05
Way4: 2021-05-31