Shulou(Shulou.com)06/02 Report--

This article will explain in detail what cool things you can do with Play, and the content of the article is of high quality, so the editor will share it with you for reference. I hope you will have some understanding of the relevant knowledge after reading this article.

Bind HTTP parameters to JAVA method parameters

With the Play framework, it is very simple to get the HTTP request parameters in the Java code, just declare that the parameter name of the method is the same as the parameter name of the HTTP request.

For example, this request:

/ articles/archive?date=08/01/08&page=2

By declaring date and page as the incoming parameters of the Java method, you can get the values of the date and page parameters in the HTTP request:

Public static void archive (Date date, Integer page) {List articles = Articles.fromArchive (date, page); render (articles);}

The Play framework automatically converts HTTP request parameters into corresponding Java objects based on the declared Java parameter type.

This automatic binding also applies to any Java object.

Public class Person {public String name; public Integer age;}

A simple action method for adding a user's controller can look like this:

Public static void add (Person p) {p.save ();}

The corresponding HTML form field uses the compound parameter name:

Name: Age:

Redirect by calling the corresponding Java method

Play has no equivalent to the Java Servlet forward command, but implementing redirection is really simple. Simply call the appropriate Java method, and Play will automatically generate the correct HTTP Redirect response to the client.

Public static void show (Long id) {Article article = Article.findById (id); render (article);} public static void edit (Long id, String title) {Article article = Article.findById (id); article.title = title; article.save (); show (id);}

Notice how the * of the edit method causes us to redirect to the page corresponding to the show method.

In any template file, you can use the same syntax to generate links:

${article.title}

The following HTML content will be generated:

My new article

Do not repeatedly pass Java objects to the template file

In most Java frameworks, in order to pass a Java object to a template file, you usually need to write something like this:

Article article = Article.findById (id); User user = User.getConnected (); Map model = new HashMap (); model.put ("article", article); model.put ("user", user); render (model)

To use Play, you only need to write:

Article article = Article.findById (id); User user = User.getConnected (); render (article, user)

Then you can get the corresponding Java variable from the template. This leaves a lot of repetitive and useless code.

JPA persistence

There is no doubt that JPA is the object-relational mapping framework (ORM) in Java domain. If you are familiar with JPA, you will be surprised how simple it has become in the Play framework. Without any configuration, Play automatically starts the JPA entity manager and automatically synchronizes when the code is modified.

And if you use play.db.jpa.Model provided by Play as a superclass, it will help you write code more beautifully. Let's take a look:

Public void messages (int page) {User connectedUser = User.find ("byEmail", connected ()). First (); List messages = Message.find ("user =? and read = false order by date desc", connectedUser) .from (page * 10) .fetch (10); render (connectedUser, messages);}

Easy-to-use file upload management

File upload management is very simple in the Play framework.

The following HTML form:

# {form @ uploadPhoto (), enctype:'multipart/form-data'} # {/}

And this Java code:

Public static void uploadPhoto (String title, File photo) {...}

It's done! It couldn't be easier, right?

So much for sharing the cool things you can do with Play. I hope the above content can help you and learn more. If you think the article is good, you can share it for more people to see.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.