Play Framework First App

Familiar Hello World

Create a new project to understand the structure of important documents

. \app

Controllers\models\views

The more popular MVC architecture at the moment

. \conf

APPLICATION.CONF engineering configuration, including database connection, etc.

Routes routing configuration, for resolving URLs

Find the. \app\views\application\index.html

Modify page content, add an input box and a button

#{extends ' main.html '/}#{set title: ' Home '/}<formAction= "@{application.sayhello ()}"Method= "Get">    <inputtype= "text"name= "MyName" />    <inputtype= "Submit"value= "Say Hello" /></form>

#{extends ' main.html '/} indicates that the page inherits from Main.html

#{set title: ' Home '/} set page title

Run the program, go to page localhost:9000, will prompt error,No route able to invoke action Application.sayhello is found

Adding SayHello methods in Application.java

 Public Static void SayHello (String myName) {        render (myName);}

Add SayHello page, add sayhello.html under. \app\views\application

#{extends ' main.html '/}#{set title: ' Home '/} < H1 > Hello ${myname?: ' Guest '}! </ H1 > <  href= "@{application.index ()}">back to form</A  >

The results are as follows:

Optimization of URLs Http://localhost:9000/application/sayhello?myName=Alex

Configure routing. \conf\routes

In */{controller}/{action} {controller}. Add after {action}:

GET     /hello                                    Application.sayhello

You can use the new URL to access the page Http://localhost:9000/hello?myName=Alex

Custom layout

Layout is the public part of all pages, modified. \app\views\main.html

< Body >         Hello World APP        </>                #{dolayout/}</  body>

#{dolayout/}   will replace the contents of the sayhello.html

Add validation

Modify the SayHello method

Import play.data.validation.Required;  Public Static void SayHello (@Required String myName) {        if(Validation.haserrors ())        {            Flash.error ("Oops, please enter your name!" );            Index ();        }        Render (MyName);}

Modify Index.html, add the following code

#{if  flash.error}    <p style= "color: #c00" >        ${flash.error}    </p> #{/if}

。。

　　

Play Framework First App