String Templates provides a template-based mechanism for composing strings. Which improves the readability and reliability of these functions.
Strings in Java are default to each function in Java. Many times we have a requirement where we need to compose messages i.e. Email Body or data structures i.e. JSON, XML
To achieve this we have to write a lot of verbose and unreliable code. String Templates provides a readable and reliable way to write code for these scenarios.
We will understand this with sample code.
I am adding JDK 21 related resources and sample codes in this git repo.
Samples for code used below is also included in this git repo.
# Example 1 —Create JSON Object Using Function
Requirement — Write a function to Create a JSON Object of three fields — first_name, last_name & country
Before JDK 21
Implementation using String.format method (there are other ways too)
public static String prepareJsonBeforeJava21(String firstName, String lastName, String country){
return String.format("{\n\t\"first_name\": \"%s\",\n\t\"last_name\": \"%s\",\n\t\"country\": \"%s\"\n}", firstName, lastName, country);
}After JDK 21
Implementation using String Templates
public static String prepareJson(String firstName, String lastName, String country){
return
"""
{
"first_name": "%s",
"last_name": "%s",
"country": "%s"
}
""".formatted(firstName, lastName, country);
}# Example 2— Prepare Email Body Function
Requirement — Write a function to prepare an email body to welcome user based on user name
Before JDK 21
Implementation using StringBuilder class (there are other ways too)
public static String prepareEmailBodyBeforeJDK21(String name){
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.append("<html>\n <body>");
stringBuilder.append(String.format("<p> Welcome %s to our planet.</p> \n", name));
stringBuilder.append("</body>\n</html>");
return stringBuilder.toString();
}After JDK 21
Implementation using String Templates
public static String prepareEmailBody(String name){
return
"""
<html>
<body>
<p> Welcome %s to our planet.</p>
</body>
</html>
""".formatted(name);
}
Using examples we saw how String Templates increased code readability and reliability where we have to create strings based on business logic.
Happy Learning
