Using Spring as a dependency injection framework with play 2.4.x?

Question

I am exploring play-scala 2.4.2 and trying to get the spring DI working with it. I see there are a lot of changes in play 2.4.x and old way of overriding the GlobalSettings.getC

Answer 1

The latest version of Play:

Create the class Global (Old Global than extended GlobaSettings):

@Singleton
public class Global {

    private static final String APPLICATION_CONTEXT = "applicationContext.xml";

    private ConfigurableApplicationContext applicationContext;

    @Inject
    public Global( ApplicationLifecycle lifecycle ) {
        applicationContext = new ClassPathXmlApplicationContext(APPLICATION_CONTEXT_XML);
        lifecycle.addStopHook( () -> {
            applicationContext.close();
            return F.Promise.pure( null );
        });
    }

}

Create the class ConfigurableApplicationContextModule:

public class ApplicationContextModule extends AbstractModule {

    @Override
    protected void configure() {
        bind( Global.class ).asEagerSingleton();
    }

}

In application.conf add this:

play.modules.enabled += "config.ApplicationContextModule"

Create file applicationContext.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

       <context:component-scan base-package="services, dao"/>

</beans>

After creating what stated above by Ranga

Answer 2

Just in case it can help someone, I also worked on a solution that is working based off of jroper's project: https://github.com/jroper/play-spring. The key was to use spring's scanning feature to "load" the Play classes:

ctx.scan(packages:_*)

with the default play's packages:

def defaultPackages(): Seq[String] = Seq("router", "play", "controllers")

The solution works with 1 hack: you need to add the @javax.inject.Named next to the @Singleton annotations in the Play classes so that Spring can scan them and load them (i.e you need to "fork" the Play version you are using, but it's a rather small and easy change). So here is my sample app with the SpringApplicationLoader: https://github.com/remithieblin/play24_spring

Answer 3

Please follow the following steps:

Step1: Add the spring dependencies in build.sbt file.

libraryDependencies += "org.springframework" % "spring-context" % "4.1.6.RELEASE"
libraryDependencies += "org.springframework" % "spring-core" % "4.1.6.RELEASE"
libraryDependencies += "org.springframework" % "spring-beans" % "4.1.6.RELEASE"
libraryDependencies += "org.springframework" % "spring-aop" % "4.1.6.RELEASE"

Step2: Create a new class (ApplicationGlobalSettings.java) and that implements with GlobalSettings class.

package com.ranga.global.settings;

import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import play.Application;
import play.GlobalSettings;
public class ApplicationGlobalSettings extends GlobalSettings { 


private static final String APPLICATION_CONTEXT_XML = "applicationContext.xml";
private ConfigurableApplicationContext applicationContext;

@Override
public void beforeStart(Application application) {      
    super.beforeStart(application);
}

@Override
public void onStart(Application application) {      
    super.onStart(application);     
    applicationContext = new ClassPathXmlApplicationContext(APPLICATION_CONTEXT_XML);           
}

@Override
public void onStop(Application application) {       
    super.onStop(application);
    if(applicationContext != null) {
        applicationContext.close();
    }
}

}

Step3: Create a new spring configuration file under conf folder (applicationContext.xml) conf\applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns:context="http://www.springframework.org/schema/context"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

   <context:component-scan base-package="com.ranga.services, com.ranga.daos"/>

</beans>

Step4: Add the newly created GlobalSettings file location to the application configuration file (conf/application.conf).

.....some more configuration here.....
# Global Objects class
application.global=com.ranga.global.settings.ApplicationGlobalSettings

Step5: Create a new service class under com.ranga.service package (HelloWorldService.java).

package com.ranga.services;
import javax.inject.Inject;
import org.springframework.stereotype.Service;

import com.ranga.daos.HelloWorldDAO;
@Service
public class HelloWorldService {

    @Inject
    private HelloWorldDAO helloWorldDAO;

    public String sayHello() {
        return helloWorldDAO.sayHello();
    }
}

Step6: Create a new dao class under com.ranga.daos package (HelloWorldDAO.java).

package com.ranga.daos;

import org.springframework.stereotype.Repository;
@Repository
public class HelloWorldDAO {
    public String sayHello() {
        return "Hello Ranga!";
    }
}

Step7: Finally inject the HelloWorldService in Application.java file.

package com.ranga.controllers;

import javax.inject.Inject;

import org.springframework.beans.factory.annotation.Autowired;

import com.ranga.services.HelloWorldService;

import play.*;
import play.mvc.*;

import views.html.*;

public class Application extends Controller {

    @Inject
    private HelloWorldService helloWorldService;

    public Result index() {         
        return ok(index.render(helloWorldService.sayHello()));
    }
}

Step8: Finally modify the index.scala.html file code.

@(message: String)

<h1>@message</h1>

Now done.. run the application.