How to get Yester day Date

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package com.javasunderesan; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; public class FindYesterDayDate { public static void main(String[] args) { FindYesterDayDate fydd = new FindYesterDayDate(); System.out.println(fydd.getYesterdayDateString()); } public String getYesterdayDateString() { String prevDate = null; Calendar cal = null; SimpleDateFormat datetimeFormatYYYYMMDD = new SimpleDateFormat("yyyy-MM-dd"); String currDate = datetimeFormatYYYYMMDD.format(new Date()); try { cal = Calendar.getInstance(); cal.setTime(datetimeFormatYYYYMMDD.parse(currDate)); cal.add(Calendar.DATE, -1); prevDate = datetimeFormatYYYYMMDD.format(cal.getTime()); } catch (Exception e) { e.printStackTrace(); } finally { cal = null; } return prevDate; } }

Write a program for a String must contain three digit using String.format()

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package com.javasunderesan; public class StringThreeDigit { public static void main(String[] args) { try { int no = 0; String formattingString = null; for (int i = 0; i < 10; i++) { formattingString = String.format("Dev - %03d", no); System.out.println(formattingString); no++; } } catch(Exception e) { e.printStackTrace(); } } }

Output

Dev -  000
Dev -  001
Dev -  002
Dev -  003
Dev -  004
Dev -  005
Dev -  006
Dev -  007
Dev -  008
Dev -  009

Write a Program to Add spaces before and After a String using String.format()

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package com.javasunderesan; public class AddSpaceBeforeAndAfterString { public static void main(String[] args) { try { String msg = "java"; System.out.println(String.format("%8s", msg)); // adding spaces // before // string ; System.out.println(String.format("%-8s", msg));// adding spaces // after // string // 8 is a number of characters String and spaces } catch (Exception e) { e.printStackTrace(); } } }

Output::

    java
java    

How to do split the String using more than one delimiter

Split the String using more than one delimiter

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package com.javasunderesan; public class SplitStringDelimitters { public static void main(String[] args) { String str = "name Java Sunderesan field computer engineering grade 9.98"; try { String[] splits = str.split("name |field |grade "); for (int i = 1; i < splits.length; i++) { System.out.println(splits[i]); } } catch (Exception e) { e.printStackTrace(); } } }

Output::
Java Sunderesan
computer engineering
9.98

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Java - String split() Method

Description:

This method has two variants and splits this string around matches of the given regular expression.

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Syntax:
Here is the syntax of this method:

public String[] split(String regex, int limit)
or
public String[] split(String regex)

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Parameter

regex : regular expression to be applied on string.

limit : limit for the number of strings in array. If it is zero, it will returns all the strings matching regex.Parameter

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Returns

array of strings

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Throws

PatternSyntaxException if pattern for regular expression is invalid

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How to do Convert the date from one format to another date object in another form Program

convert-the-date-from-one-format-to-another-date-object-in-another-form Program

   package com.javasunderesan;

import java.text.SimpleDateFormat;
import java.util.Date;

public class ConvertDateObject {

 public static void main(String[] args) {
  SimpleDateFormat ddmmyyyy = new SimpleDateFormat("dd/mm/yyyy");
  SimpleDateFormat datetimeFormatyyyymmdd = new SimpleDateFormat("yyyy-mm-dd");
  try {
   ConvertDateObject cdo = new ConvertDateObject();
   String fromDate = "26/05/2016";
   System.out
     .println("Converted Date Time::" + cdo.convertDateType(fromDate, ddmmyyyy, datetimeFormatyyyymmdd));

  } catch (Exception e) {
   e.printStackTrace();
  }

 }

 private String convertDateType(String date, SimpleDateFormat orgFormat, SimpleDateFormat targetFormat) {
  String formattedDate = null;
  try {
   Date calDate = orgFormat.parse(date);
   formattedDate = targetFormat.format(calDate); // 20120821
  } catch (Exception e) {
   e.printStackTrace();
  }
  return formattedDate;
 }

}

Output:: Converted Date Time::2016-05-26

parse() and format() method used to convert One date object to another date Object

public final String format(Date date)

Formats a Date into a date/time string.
Parameters:
date - the time value to be formatted into a time string.
Returns:
the formatted time string.

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Parsing a Date

Parse()

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How to calculate difference between two date String in Java

Parsing Date

public Date parse(String source) throws ParseException

Parses text from the beginning of the given string to produce a date. The method may not use the entire text of the given string.
See the parse(String, ParsePosition) method for more information on date parsing.
Parameters:
source - A String whose beginning should be parsed.
Returns:
A Date parsed from the string.
Throws: ParseException - if the beginning of the specified string cannot be parsed.

   package com.javasunderesan;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class CompareDateTime {

 public static void main(String[] args) {
  SimpleDateFormat sdf = new SimpleDateFormat("dd/mm/yyyy");  
  
  Date start = null, end = null;
  String fromDate = null;
  String toDate = null;
  try {
   CompareDateTime compareDate = new CompareDateTime();
   fromDate = "24/05/2016";
   toDate = "25/05/2016";
   start = sdf.parse(fromDate);
   end = sdf.parse(toDate);   
   System.out.println("Days Between " + start + " and " + end + ":::" +compareDate.daysBetween(start, end));
  } catch (ParseException e) {
    e.printStackTrace();
  }

 }

 private Long daysBetween(Date d1, Date d2) {
  return (Long) ((d2.getTime() - d1.getTime()) / (1000 * 60 * 60 * 24));
 }
}

output: Days Between Sun Jan 24 00:05:00 IST 2016 and Mon Jan 25 00:05:00 IST 2016:::1