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Eugen
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Merge pull request eugenp#854 from dkornishev/master
Spring Constructor-Based DI
2 parents 1ba76d7 + 6115291 commit 615ddc1

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‎spring-core/src/main/java/com/baeldung/constructordi/Config.java‎

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package com.baeldung.constructordi;
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import org.springframework.context.annotation.Bean;
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import org.springframework.context.annotation.ComponentScan;
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import org.springframework.context.annotation.Configuration;
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import com.baeldung.constructordi.domain.Engine;
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import com.baeldung.constructordi.domain.Transmission;
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@Configuration
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@ComponentScan("com.baeldung.constructordi")
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public class Config {
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@Bean
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public Engine engine() {
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return new Engine("v8", 5);
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}
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@Bean
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public Transmission transmission() {
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return new Transmission("sliding");
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}
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}

‎spring-core/src/main/java/com/baeldung/constructordi/SpringRunner.java‎

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package com.baeldung.constructordi;
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import org.springframework.context.ApplicationContext;
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import org.springframework.context.annotation.AnnotationConfigApplicationContext;
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import org.springframework.context.support.ClassPathXmlApplicationContext;
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import com.baeldung.constructordi.domain.Car;
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public class SpringRunner {
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public static void main(String[] args) {
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Car toyota = getCarFromXml();
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System.out.println(toyota);
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toyota = getCarFromJavaConfig();
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System.out.println(toyota);
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}
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private static Car getCarFromJavaConfig() {
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ApplicationContext context = new AnnotationConfigApplicationContext(Config.class);
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return context.getBean(Car.class);
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}
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private static Car getCarFromXml() {
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ApplicationContext context = new ClassPathXmlApplicationContext("baeldung.xml");
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return context.getBean(Car.class);
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}
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}

‎spring-core/src/main/java/com/baeldung/constructordi/domain/Car.java‎

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package com.baeldung.constructordi.domain;
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import org.springframework.beans.factory.annotation.Autowired;
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import org.springframework.stereotype.Component;
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@Component
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public class Car {
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private Engine engine;
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private Transmission transmission;
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@Autowired
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public Car(Engine engine, Transmission transmission) {
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this.engine = engine;
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this.transmission = transmission;
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}
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@Override
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public String toString() {
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return String.format("Engine: %s Transmission: %s", engine, transmission);
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}
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}

‎spring-core/src/main/java/com/baeldung/constructordi/domain/Engine.java‎

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package com.baeldung.constructordi.domain;
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public class Engine {
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private String type;
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private int volume;
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public Engine(String type, int volume) {
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this.type = type;
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this.volume = volume;
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}
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@Override
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public String toString() {
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return String.format("%s %d", type, volume);
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}
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}

‎spring-core/src/main/java/com/baeldung/constructordi/domain/Transmission.java‎

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package com.baeldung.constructordi.domain;
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public class Transmission {
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private String type;
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public Transmission(String type) {
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this.type = type;
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}
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@Override
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public String toString() {
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return String.format("%s", type);
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}
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}

‎spring-core/src/main/resources/baeldung.xml‎

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<beans xmlns="http://www.springframework.org/schema/beans"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://www.springframework.org/schema/beans
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http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
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<bean id="toyota" class="com.baeldung.constructordi.domain.Car">
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<constructor-arg index="0" ref="engine"/>
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<constructor-arg index="1" ref="transmission"/>
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</bean>
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<bean id="engine" class="com.baeldung.constructordi.domain.Engine">
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<constructor-arg index="0" value="v4"/>
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<constructor-arg index="1" value="2"/>
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</bean>
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<bean id="transmission" class="com.baeldung.constructordi.domain.Transmission">
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<constructor-arg value="sliding"/>
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</bean>
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</beans>

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