play 2.1.1 flash example.

$ cat conf/routes 
# Routes
# This file defines all application routes (Higher priority routes first)
# ~~~~

# Home page
GET     /                           controllers.Application.index()
GET     /noflash                    controllers.Application.indexNoFlash()

# Map static resources from the /public folder to the /assets URL path
GET     /assets/*file               controllers.Assets.at(path="/public", file)



$ cat app/controllers/Application.java 
package controllers;

import play.mvc.Controller;
import play.mvc.Result;
import views.html.index;

public class Application extends Controller {
  
    public static Result index() {
        flash("success", "foo");
        return ok(index.render("Your new application is ready."));
    }

    public static Result indexNoFlash() {
        return ok(index.render("Your new application is ready."));
    }
}



$ cat app/views/index.scala.html 
@(message: String)

@main("Welcome to Play 2.1") {
    <div>
    @if(flash.containsKey("success")) {
        <strong>flash success: </strong> @flash.get("success")
    } else {
        <strong>no flash at all</strong>
    }
    </div>
    <div>
        <a href='@routes.Application.index()'>Show page with flash.</a>
        <a href='@routes.Application.indexNoFlash()'>Show page with no flash.</a>
    </div>
}