The MessageFormat class in java.text package is used to produce concatenated messages that include dynamic values, such as numbers, dates, or strings, in a template format. Unlike string concatenation, MessageFormat is locale-sensitive and cleaner for formatting complex messages with placeholders.
Key Features:
- Supports indexed placeholders like
{0},{1}, etc. - Can format numbers, dates, and strings.
- Localized formatting.
- Reusable format templates.
Common Used Methods
Simple Program
import java.text.MessageFormat;
public class SimpleMessageFormatExample {
public static void main(String[] args) {
String pattern = "Hello {0}, you have {1} new messages.";
String formattedMessage = MessageFormat.format(pattern, "Mahesh", 5);
System.out.println(formattedMessage);
}
}
/*
Hello Mahesh, you have 5 new messages.
*/Problem Statement
Paani and Mahesh are building a Bank Notification System. Whenever a transaction occurs, the system should send a personalized notification to the customer with the following details:
- Customer Name
- Transaction Amount
- Transaction Type (Credit/Debit)
- Current Balance
Use the MessageFormat class to create such a dynamic message template.
import java.text.MessageFormat;
public class BankNotificationSystem {
public static void main(String[] args) {
// Pattern with placeholders
String pattern = "Dear {0}, your account has been {1} with ₹{2,number,#,##0.00}. "
+ "Your current balance is ₹{3,number,#,##0.00}.";
// Sample data for multiple customers
Object[][] transactions = {
{"Mahesh", "credited", 2500.75, 10500.50},
{"LotusJavaPrince", "debited", 1200.00, 8800.50},
{"Paani", "credited", 7000.00, 15800.75}
};
System.out.println("----- Bank Notifications -----");
for (Object[] transaction : transactions) {
String message = MessageFormat.format(pattern, transaction);
System.out.println(message);
}
}
}
/*
----- Bank Notifications -----
Dear Mahesh, your account has been credited with ₹2,500.75. Your current balance is ₹10,500.50.
Dear LotusJavaPrince, your account has been debited with ₹1,200.00. Your current balance is ₹8,800.50.
Dear Paani, your account has been credited with ₹7,000.00. Your current balance is ₹15,800.75.
*/The MessageFormat class in Java offers a clean and structured way to build messages with dynamic values, making it ideal for logs, notifications, and multi-language applications.MessageFormat is a vital class when building user-friendly messages with variable data, especially in enterprise and internationalized applications.