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Page 270 of 589
Java Program to display previous day from GregorianCalender
For GregorianCalendar class, import the following package.import java.util.GregorianCalendar;Create an object.GregorianCalendar cal = (GregorianCalendar) GregorianCalendar.getInstance();Now, use the following field and add() method with a negative one (-1) to display the previous day.cal.add((GregorianCalendar.DATE), -1)Exampleimport java.util.Calendar; import java.util.GregorianCalendar; public class Demo { public static void main(String[] a) { GregorianCalendar cal = (GregorianCalendar) GregorianCalendar.getInstance(); System.out.println("Current date: " + cal.getTime()); // past date cal.add((GregorianCalendar.DATE), -1); System.out.println("Modified date (Previous Day): " + cal.getTime()); } }OutputCurrent date: Mon Nov 19 18:12:53 UTC 2018 Modified date (Previous Day): Sun Nov 18 18:12:53 UTC 2018
Read MoreDetermine day of week in month from Gregorian Calendar in Java
To work with the GregorianCalendar class, import the following package −import java.util.GregorianCalendar;To get the day of week in month, use the following field −cal.get(Calendar.DAY_OF_WEEK_IN_MONTH)Above, cal is the GregorianCalendar object we created before −GregorianCalendar cal = new GregorianCalendar();The following is an example −Exampleimport java.util.GregorianCalendar; import java.util.Calendar; import java.util.Date; public class Demo { public static void main(String[] args) { GregorianCalendar cal = new GregorianCalendar(); // date information System.out.println("Date Information.........."); System.out.println("Year = " + cal.get(Calendar.YEAR)); System.out.println("Month = " + (cal.get(Calendar.MONTH) + 1)); System.out.println("Date = ...
Read MoreJava Program to return a Date set to the last possible millisecond of the day before midnight
Let us first set the calendar object.Calendar calendar = Calendar.getInstance();Use the getMaximum() method in Java to returns the maximum value for the given calendar field. We will use it to set the minute, hours second and milliseconds.For hour and minute.calendar.set(Calendar.HOUR_OF_DAY, calendar.getMaximum(Calendar.HOUR_OF_DAY)); calendar.set(Calendar.MINUTE, calendar.getMaximum(Calendar.MINUTE));For second and milliseconds.// second calendar.set(Calendar.SECOND, calendar.getMaximum(Calendar.SECOND)); // millisecond calendar.set(Calendar.MILLISECOND, calendar.getMaximum(Calendar.MILLISECOND));The following is an example that returns a Date set to the last possible millisecond of the day before midnight.Exampleimport java.util.Calendar; import java.util.GregorianCalendar; public class Demo { public static void main(String[] argv) throws Exception { Calendar calendar = Calendar.getInstance(); // hour ...
Read MoreJava Program to return a Date set to the first possible millisecond of the day after midnight
Let us first set the calendar object.Calendar calendar = Calendar.getInstance();Use the getMinimum() method in Java to return the minimum value for the given calendar field. We will use it to set the minute, hours second and milliseconds.For hour and minute.calendar.set(Calendar.HOUR_OF_DAY, calendar.getMinimum(Calendar.HOUR_OF_DAY)); calendar.set(Calendar.MINUTE, calendar.getMinimum(Calendar.MINUTE));For second and milliseconds.// second calendar.set(Calendar.SECOND, calendar.getMinimum(Calendar.SECOND)); // millisecond calendar.set(Calendar.MILLISECOND, calendar.getMinimum(Calendar.MILLISECOND));The following is an example that returns a Date set to the first possible millisecond of the day after midnight.Exampleimport java.util.Calendar; import java.util.GregorianCalendar; public class Demo { public static void main(String[] argv) throws Exception { Calendar calendar = Calendar.getInstance(); // hour ...
Read MoreConvert double primitive type to a Double object in Java
To convert double primitive type to a Double object, you need to use Double constructor.Let’s say the following is our double primitive.// double primitive double val = 23.78;To convert it to a Double object, use Double constructor.// Double object Double ob = new Double(val);Examplepublic class Demo { public static void main(String args[]) { // double primitive double val = 23.78; // Double object Double ob = new Double(val); System.out.println(ob); } }Output23.78
Read MoreFormat double type in Java
Let’s say we have the following three values −double val1 = 15.546; double val2 = 25.87; double val3 = Math.PI;Let us now format these double-type numbers. Firstly, we are formatting Euler’s number with Math.exp(). After that, we have also evaluated log. The %.3f you can see here is what we used for formatting the numbers.System.out.printf("exp(%.3f) = %.3f%n", val1, Math.exp(val1)); System.out.printf("log = %.3f%n", val1, Math.log(val1));The following is an example where we have also shown other ways to format double in Java.Examplepublic class Demo { public static void main(String args[]) { double val1 = 15.546; ...
Read MorePrecision on a number format in Java
You can include a precision specifier to the following format specifiers −%f %e %g %sOn floating point, the number of decimal places is known.Let’s say we declared a Formatter object −Formatter f1 = new Formatter();Now, we want 3 decimal places. For that, use 1.3f −f1.format("%1.3f", 29292929.98765432);The above will return the number with 3 decimal places −29292929.988The following is the final example −Exampleimport java.util.Formatter; public class Demo { public static void main(String args[]) { Formatter f1, f2, f3; f1 = new Formatter(); f1.format("%1.3f", 29292929.98765432); System.out.println(f1); f2 = new Formatter(); f2.format("%1.7f", 29292929.98765432); System.out.println(f2); ...
Read MoreJava Program to add leading zeros to a number
To add leading zeros to a number, you need to format the output. Let’s say we need to add 4 leading zeros to the following number with 3 digits.int val = 290;For adding 4 leading zeros above, we will use %07d i.e. 4+3 = 7. Here, 3, as shown above, is the number with 3 digits.String.format("%07d", val);The following is the final example.Exampleimport java.util.Formatter; public class Demo { public static void main(String args[]) { int val = 290; System.out.println("Integer: "+val); String formattedStr = String.format("%07d", val); System.out.println("With leading zeros = " + formattedStr); } }OutputInteger: 290 With leading zeros = 0000290
Read MoreGet all digits from a string in Java
Let’s say the following is our string.String str = "DEMO98 TE4567XT";To display only the digits from the above string, we have used the replaceAll() method and replace all the characters with empty.str.replaceAll("\D", ""))The following is the final example that displays only digits from the string.Examplepublic class Demo { public static void main(String[] args) { String str = "DEMO98 TE4567XT"; System.out.println("String = "+str); System.out.println("Displaying digits: "+str.replaceAll("\D", "")); } }OutputString = DEMO98 TE4567XT Displaying digits: 984567
Read MoreConcatenate null to a string in Java
To concatenate null to a string, use the + operator.Let’s say the following is our string.String str = "Demo Text";We will now see how to effortlessly concatenate null to string.String strNULL = str + "null";The following is the final example.Examplepublic class Demo { public static void main(String[] args) { String str = "Demo Text"; System.out.println("String = "+str); String strNULL = str + "null"; System.out.println("String concatenated with NULL: "+strNULL); } }OutputString = Demo Text String concatenated with NULL: Demo Textnull
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