JSTL/JSP EL (Expression Language) in a non JSP (standalone) context

Question

Can anyone recommend a framework for templating/formatting messages in a standalone application along the lines of the JSP EL (Expression Language)?

I would expect t

Answer 1

I would go for the Spring Expression language:

http://docs.spring.io/spring/docs/current/spring-framework-reference/html/expressions.html

A few examples which demonstrate the power (the first two are from the documentation):

int year = (Integer) parser.parseExpression("Birthdate.Year + 1900").getValue(context);

String city = (String) parser.parseExpression("placeOfBirth.City").getValue(context);

// weekday is a String, e.g. "Mon", time is an int, e.g. 1400 or 900
{"Thu", "Fri"}.contains(weekday) and time matches '\d{4}'

Expressions can also use object properties:

public class Data {
    private String name; // getter and setter omitted
}

Data data = new Data();
data.setName("John Doe");

ExpressionParser p = new SpelExpressionParser();
Expression e = p.parseExpression("name == 'John Doe'");
Boolean r = (Boolean) e.getValue(data); // will return true

e = p.parseExpression("Hello " + name + ", how are you ?");
String text = e.getValue(data, String.class); // text will be "Hello John Doe, how are you ?"

Answer 2

Re: Jasper and Juel being built for 1.5: And then I discovered RetroTranslator (http://retrotranslator.sourceforge.net/). Once retrotranslated, EL and Jasper works like a charm

Answer 3

AAh. Whereas with MessageFormat, I can do

Dear {0}. Your order will be dispatched on {1,date,EEE dd MMM yyyy}

where parameter #1 is a Date object and it gets formatted according to the pattern, there is no equivalent in EL.

In JSP, I would have used, perhaps, a format tag. In this standalone example, I am going to have to format the Date as a String in my code prior to evaluating the expression.

Answer 4

Freemarker would do exactly what you need. This is a template engine with a syntax very similar to JSP :

http://freemarker.org/

Answer 5

I would recommend looking into Apache Velocity. It is quite simple and lightweight.

We are currently using it for our e-mail templates, and it works very well.

Answer 6

You can use Casper very similar to jsp and easy to use : Casper