Le traduzioni sono generate tramite traduzione automatica. In caso di conflitto tra il contenuto di una traduzione e la versione originale in Inglese, quest'ultima prevarrà.

# Esempio di Java
<a name="examples-java"></a>

Questo esempio mostra come utilizzare Amazon Polly per lo streaming vocale da un'applicazione basata su Java. Nell'esempio viene utilizzato [AWS SDK per Java](https://aws.amazon.com/documentation/sdk-for-java/) per leggere il testo specificato utilizzando una voce selezionata da un elenco.

Il codice mostrato copre le attività principali, ma esegue solo un controllo minimo degli errori. Se Amazon Polly rileva un errore, l'applicazione viene terminata. 

Per eseguire questa applicazione di esempio, è necessario quanto elencato di seguito:
+  Java Development Kit (JDK) di Java 8 
+  [AWS SDK per Java](https://aws.amazon.com/documentation/sdk-for-java/) 
+  [Apache Maven](http://maven.apache.org/) 

**Per testare l'applicazione**

1. Verifica che la variabile di ambiente JAVA\$1HOME sia impostata per il JDK.

   Ad esempio, se hai installato JDK 1.8.0\$1121 su Windows nel percorso `C:\Program Files\Java\jdk1.8.0_121`, digita quanto segue al prompt dei comandi:

   ```
   set JAVA_HOME=""C:\Program Files\Java\jdk1.8.0_121""
   ```

   Se hai installato JDK 1.8.0\$1121 su Linux nel percorso `/usr/lib/jvm/java8-openjdk-amd64`, digita quanto segue al prompt dei comandi: 

   ```
   export JAVA_HOME=/usr/lib/jvm/java8-openjdk-amd64
   ```

1. Imposta le variabili di ambiente Maven per eseguire Maven dalla riga di comando. 

   Ad esempio, se hai installato Maven 3.3.9 su Windows nel percorso `C:\Program Files\apache-maven-3.3.9`, digita quanto segue al prompt dei comandi:

   ```
   set M2_HOME=""C:\Program Files\apache-maven-3.3.9""
   set M2=%M2_HOME%\bin
   set PATH=%M2%;%PATH%
   ```

   Se hai installato Maven 3.3.9 su Linux nel percorso `/home/ec2-user/opt/apache-maven-3.3.9`, digita quanto segue al prompt dei comandi:

   ```
   export M2_HOME=/home/ec2-user/opt/apache-maven-3.3.9
   export M2=$M2_HOME/bin
   export PATH=$M2:$PATH
   ```

1. Crea una nuova directory denominata `polly-java-demo`. 

1. Nella directory `polly-java-demo` crea un nuovo file denominato `pom.xml` e incollavi il seguente codice: 

   ```
   <project xmlns="http://maven.apache.org/POM/4.0.0" 
                       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   	<modelVersion>4.0.0</modelVersion>
   	<groupId>com.amazonaws.polly</groupId>
   	<artifactId>java-demo</artifactId>
   	<version>0.0.1-SNAPSHOT</version>
   
   	<dependencies>
   		<!-- https://mvnrepository.com/artifact/com.amazonaws/aws-java-sdk-polly -->
   		<dependency>
   			<groupId>com.amazonaws</groupId>
   			<artifactId>aws-java-sdk-polly</artifactId>
   			<version>1.11.77</version>
   		</dependency>
   		<!-- https://mvnrepository.com/artifact/com.googlecode.soundlibs/jlayer -->
   		<dependency>
   			<groupId>com.googlecode.soundlibs</groupId>
   			<artifactId>jlayer</artifactId>
   			<version>1.0.1-1</version>
   		</dependency>
   
   	</dependencies>
   	<build>
   		<plugins>
   			<plugin>
   				<groupId>org.codehaus.mojo</groupId>
   				<artifactId>exec-maven-plugin</artifactId>
   				<version>1.2.1</version>
   				<executions>
   					<execution>
   						<goals>
   							<goal>java</goal>
   						</goals>
   					</execution>
   				</executions>
   				<configuration>
   					<mainClass>com.amazonaws.demos.polly.PollyDemo</mainClass>
   				</configuration>
   			</plugin>
   		</plugins>
   	</build>
   </project>
   ```

1.  Crea una nuova directory denominata `polly` nel percorso `src/main/java/com/amazonaws/demos`. 

1.  Nella directory `polly` crea un nuovo file di origine Java denominato `PollyDemo.java` e incolla il seguente codice: 

   ```
   package com.amazonaws.demos.polly;
   
   import java.io.IOException;
   import java.io.InputStream;
   
   import com.amazonaws.ClientConfiguration;
   import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
   import com.amazonaws.regions.Region;
   import com.amazonaws.regions.Regions;
   import com.amazonaws.services.polly.AmazonPollyClient;
   import com.amazonaws.services.polly.model.DescribeVoicesRequest;
   import com.amazonaws.services.polly.model.DescribeVoicesResult;
   import com.amazonaws.services.polly.model.OutputFormat;
   import com.amazonaws.services.polly.model.SynthesizeSpeechRequest;
   import com.amazonaws.services.polly.model.SynthesizeSpeechResult;
   import com.amazonaws.services.polly.model.Voice;
   
   import javazoom.jl.player.advanced.AdvancedPlayer;
   import javazoom.jl.player.advanced.PlaybackEvent;
   import javazoom.jl.player.advanced.PlaybackListener;
   
   public class PollyDemo {
   
   	private final AmazonPollyClient polly;
   	private final Voice voice;
   	private static final String SAMPLE = "Congratulations. You have successfully built this working demo 
   	of Amazon Polly in Java. Have fun building voice enabled apps with Amazon Polly (that's me!), and always 
   	look at the AWS website for tips and tricks on using Amazon Polly and other great services from AWS";
   
   	public PollyDemo(Region region) {
   		// create an Amazon Polly client in a specific region
   		polly = new AmazonPollyClient(new DefaultAWSCredentialsProviderChain(), 
   		new ClientConfiguration());
   		polly.setRegion(region);
   		// Create describe voices request.
   		DescribeVoicesRequest describeVoicesRequest = new DescribeVoicesRequest();
   
   		// Synchronously ask Amazon Polly to describe available TTS voices.
   		DescribeVoicesResult describeVoicesResult = polly.describeVoices(describeVoicesRequest);
   		voice = describeVoicesResult.getVoices().get(0);
   	}
   
   	public InputStream synthesize(String text, OutputFormat format) throws IOException {
   		SynthesizeSpeechRequest synthReq = 
   		new SynthesizeSpeechRequest().withText(text).withVoiceId(voice.getId())
   				.withOutputFormat(format).withEngine("neural");
   		SynthesizeSpeechResult synthRes = polly.synthesizeSpeech(synthReq);
   
   		return synthRes.getAudioStream();
   	}
   
   	public static void main(String args[]) throws Exception {
   		//create the test class
   		PollyDemo helloWorld = new PollyDemo(Region.getRegion(Regions.US_EAST_1));
   		//get the audio stream
   		InputStream speechStream = helloWorld.synthesize(SAMPLE, OutputFormat.Mp3);
   
   		//create an MP3 player
   		AdvancedPlayer player = new AdvancedPlayer(speechStream,
   				javazoom.jl.player.FactoryRegistry.systemRegistry().createAudioDevice());
   
   		player.setPlayBackListener(new PlaybackListener() {
   			@Override
   			public void playbackStarted(PlaybackEvent evt) {
   				System.out.println("Playback started");
   				System.out.println(SAMPLE);
   			}
   			
   			@Override
   			public void playbackFinished(PlaybackEvent evt) {
   				System.out.println("Playback finished");
   			}
   		});
   		
   		
   		// play it!
   		player.play();
   		
   	}
   }
   ```

1.  Torna alla directory `polly-java-demo` per pulire, compilare ed eseguire la demo: 

   ```
   mvn clean compile exec:java
   ```