Java: Create message with MessageFormat class


Creating a message string is very easy, but creating it with more effective way that's matter. Most of time when we write the code for message string, we use "+" operator on string. But it become complex when we have to deal with lots of pieces of string.

It can be worse when we have to deal with number, date and currency type data with locale setting.

Below are few test data which use common way of creating the message string.

DateFormat df = DateFormat.getDateInstance(DateFormat.DEFAULT);
DateFormat tf = DateFormat.getTimeInstance(DateFormat.DEFAULT);
Date today = new Date();
String text = "Work";
int num = 7;
 
String meesage1 = "Time= " + tf.format(today) +
   ", Date= " + df.format(today) +
   ", Text= " + text +
   ", Number= " + num + ".";
System.out.println(meesage1);
   
String message2 = new StringBuffer("Time= ").append(tf.format(today))
  .append(", Date= ").append(df.format(today))
  .append(", Text= ").append(text)
  .append(", Number= ").append(num)
  .append(".").toString();
System.out.println(message2);
   

Output:->
Time= 11:41:17 AM, Date= Dec 3, 2011, Text= Work, Number= 7.
Time= 11:41:17 AM, Date= Dec 3, 2011, Text= Work, Number= 7.


And here is the more easy way of creating the string message. (after using the MessageFormat class)

Date today = new Date();
String text = "Work";
int num = 7;

String message3 = MessageFormat.format(
     "Time= {1,time}, Date= {1,date}, Text= {2}, Number= {0,number,integer}.",
     num, today, text);
System.out.println(message3);

Output:->
Time= 11:41:17 AM, Date= Dec 3, 2011, Text= Work, Number= 7.


Some more details form java doc

Format Element
{ ArgumentIndex , [FormatType] , [FormatStyle] }

FormatType:
number | date | time | choice


FormatStyle:
short
medium
long
full
integer
currency
percent
SubformatPattern


Format TypeFormat StyleSubformat Created
(none)(none)null
number(none)NumberFormat.getInstance(getLocale())
integerNumberFormat.getIntegerInstance(getLocale())
currencyNumberFormat.getCurrencyInstance(getLocale())
percentNumberFormat.getPercentInstance(getLocale())
SubformatPatternnew DecimalFormat(subformatPattern, DecimalFormatSymbols.getInstance(getLocale()))
date(none)DateFormat.getDateInstance(DateFormat.DEFAULT, getLocale())
shortDateFormat.getDateInstance(DateFormat.SHORT, getLocale())
mediumDateFormat.getDateInstance(DateFormat.DEFAULT, getLocale())
longDateFormat.getDateInstance(DateFormat.LONG, getLocale())
fullDateFormat.getDateInstance(DateFormat.FULL, getLocale())
SubformatPatternnew SimpleDateFormat(subformatPattern, getLocale())
time(none)DateFormat.getTimeInstance(DateFormat.DEFAULT, getLocale())
shortDateFormat.getTimeInstance(DateFormat.SHORT, getLocale())
mediumDateFormat.getTimeInstance(DateFormat.DEFAULT, getLocale())
longDateFormat.getTimeInstance(DateFormat.LONG, getLocale())
fullDateFormat.getTimeInstance(DateFormat.FULL, getLocale())
SubformatPatternnew SimpleDateFormat(subformatPattern, getLocale())
choiceSubformatPatternnew ChoiceFormat(subformatPattern)

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