![]() ![]() Why can't this String be converted back to an int? This attempt results in the following error: Exception in thread "main" : For input string: "cafebabe"įirst of all: The String s contains "cafebabe" as expected. Int i = Integer.parseInt(s, 16) Code language: Java ( java ) It becomes interesting (not to say: confusing) if, for example, we convert the valid int value 0xCAFEBABE into a hex String and then back into an int: int hex = 0xCAFEBABE In all the above cases, the number to be parsed must be within the range Integer.MIN_VALUE (= -2 31 = -2,147,483,648) to Integer.MAX_VALUE (= 2 31-1 = 2,147,483,647). A hexadecimal number can be parsed as follows: The parameter radix specifies the base of the number system. Integer i = Integer.valueOf(s, radix) (→ JavaDoc).int i = Integer.parseInt(s, radix) (→ JavaDoc).To parse other number systems, the following overloaded methods are available: Integer.parseInt("1,000") // Thousands separator not allowed.Integer.parseInt("3.14") // Decimal point not allowed.Integer.parseInt(" 1") // Space not allowed.Integer.parseInt("") // Empty string not allowed.The following Strings are not allowed and result in NumberFormatExceptions: The String to convert must contain only digits, optionally with a plus or minus sign in front. The second method internally calls the first method and converts the result to an Integer object. Integer i = Integer.valueOf(s) (→ JavaDoc).int i = Integer.parseInt(s) (→ JavaDoc).Let's first look at the options to parse a String into an int (or Integer). You can find the source code for this article in my GitHub repository. Today you will learn what to consider in the opposite direction, i.e., when parsing a String to an int. Use them and adapt into your own code.In the previous article, I showed you that "" + i is the fastest way to convert an int into a String in Java. Migrated into Java SE 8 as package java.time.īy the way, if you need to use any of the code shown in this blog, feel free to However, thanks to the implementation of JSR 310, Joda-Time is now Iĭemonstrated that common date object types can be used to convert into string,īut most of them are hard to understand, and time-zone is not well supported. ![]() In this blog, we have seen different methods to create a date object and theĪssociated way to cast that object into an ISO 8601 date representation. Patterns for formatting and parsing are available in the Javadoc of ofPattern ( "yyyy-MM-dd'T'HH:mm:ss.SSSXXX" ). Use customized date-time pattern: // Conversion DateTimeFormatter. of ( "CET" )) // Conversion String text = DateTimeFormatter. Let’s see the code: // Input ZonedDateTime d = LocalDate. Means that January is equal to 1 instead of 0, so you can use the digit Then this object accepts a formatter toįormat the date representation in string. It uses a builder to construct theĭate time with time zone step-by-step. Solution among all the possibiliites here. The package java.time, formerly Joda-Time, provides the most elegant getTimeZone ( "CET" )) String text = sdf. getTime () // Conversion SimpleDateFormat sdf sdf = new SimpleDateFormat ( "yyyy-MM-dd'T'HH:mm:ss.SSSXXX" ) sdf. FEBRUARY, 16, 20, 22, 28 ) Date date = calendar. Input GregorianCalendar calendar calendar = new GregorianCalendar ( 2017, Calendar. format ( date ) // Output // "T20:22:28.000+01:00" įor gregorian calendar, we don’t need to set explicitly the millisecond datepart Such line will lead to an erroneous value for millisecond. Please be aware that setting the field of millisecond is necessary: lack of When using Calendar, we need to get an instance, then build a date object with currentTimeMillis ()) // Conversion SimpleDateFormat sdf sdf = new SimpleDateFormat ( "yyyy-MM-dd'T'HH:mm:ss.SSSXXX" ) sdf. You can see the difference in the following paragraphs. This is a little bit tricky because we’re using the current time, Here’s an example to demonstrate how to convert a to ISO 8601ĭate string. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |