gangadkho@gmail.com

spring-core/src/main/java/com/baeldung/dependencyinjections/AppConfig.java

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+package com.baeldung.dependencyinjections;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class AppConfig {
+
+    @Bean
+    public WebsiteControllerConstructorInjection websiteControllerConstructorInjection() {
+        return new WebsiteControllerConstructorInjection(homepageService());
+    }
+
+    @Bean
+    public HomepageService homepageService() {
+        return new HomepageService();
+    }
+
+    @Bean
+    public WebsiteControllerSetterInjection websiteControllerSetterInjection() {
+        return new WebsiteControllerSetterInjection();
+    }
+}

spring-core/src/main/java/com/baeldung/dependencyinjections/HomepageService.java

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+package com.baeldung.dependencyinjections;
+
+import org.springframework.stereotype.Service;
+
+@Service
+public class HomepageService {
+
+    public String getContents() {
+        return "Home page contents";
+    }
+}

spring-core/src/main/java/com/baeldung/dependencyinjections/Website.java

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+package com.baeldung.dependencyinjections;
+
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+
+public class Website {
+
+    @SuppressWarnings("resource")
+    public static void main(String[] args) {
+
+        ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
+
+        WebsiteControllerConstructorInjection controller = context.getBean(WebsiteControllerConstructorInjection.class);
+        System.out.println("The contents of the Website includes : " + controller.getContentsViaConstructorInjection());
+
+        WebsiteControllerSetterInjection controllerwithSetterInjection = (WebsiteControllerSetterInjection) context.getBean("websiteControllerSetterInjection");
+        System.out.println("The contents of the Website includes : " + controllerwithSetterInjection.getContentsViaSetterInjection());
+    }
+}

spring-core/src/main/java/com/baeldung/dependencyinjections/WebsiteControllerConstructorInjection.java

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+package com.baeldung.dependencyinjections;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class WebsiteControllerConstructorInjection {
+
+    private HomepageService homeService;
+
+    @Autowired
+    public WebsiteControllerConstructorInjection(HomepageService homeService) {
+        this.homeService = homeService;
+    }
+
+    public String getContentsViaConstructorInjection() {
+        return homeService.getContents();
+    }
+
+}

spring-core/src/main/java/com/baeldung/dependencyinjections/WebsiteControllerSetterInjection.java

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+package com.baeldung.dependencyinjections;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class WebsiteControllerSetterInjection {
+
+    private HomepageService homeService;
+
+    @Autowired
+    public void setHomepageService(HomepageService homeService) {
+        this.homeService = homeService;
+    }
+
+    public String getContentsViaSetterInjection() {
+        return homeService.getContents();
+    }
+}

spring-core/src/main/resources/dependencyinjections-context.xml

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+<beans xmlns="http://www.springframework.org/schema/beans"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
+	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
+	xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
+	xmlns:task="http://www.springframework.org/schema/task" xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.2.xsd">
+
+   <context:annotation-config/>	
+
+	<bean id="homeService" class="com.baeldung.dependencyinjections.HomepageService">
+	</bean>
+
+	<bean id="websiteControllerConstructorInjection"
+		class="com.baeldung.dependencyinjections.WebsiteControllerConstructorInjection">
+		<constructor-arg ref="homeService" />
+	</bean>	
+
+	<bean id="websiteControllerSetterInjection"
+		class="com.baeldung.dependencyinjections.WebsiteControllerSetterInjection">		
+	</bean>		
+
+</beans>

spring-core/src/test/java/com/baeldung/dependencyinjections/WebsiteTest.java

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+package com.baeldung.dependencyinjections;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.support.ClassPathXmlApplicationContext;
+
+public class WebsiteTest {
+
+    ApplicationContext annotationContext = new AnnotationConfigApplicationContext(AppConfig.class);
+    ApplicationContext xmlContext = new ClassPathXmlApplicationContext("dependencyinjections-context.xml");
+
+    public static final String EXPECTED_STRING = "Home page contents";
+
+    @Test
+    public void testAnnotationConfigConstructorBasedDI() {
+        WebsiteControllerConstructorInjection controller = annotationContext.getBean(WebsiteControllerConstructorInjection.class);
+        assertEquals(EXPECTED_STRING, controller.getContentsViaConstructorInjection());
+    }
+
+    @Test
+    public void testXMLConfigConstructorBasedDI() {
+        WebsiteControllerConstructorInjection controller = xmlContext.getBean(WebsiteControllerConstructorInjection.class);
+        assertEquals(EXPECTED_STRING, controller.getContentsViaConstructorInjection());
+    }
+
+    @Test
+    public void testAnnotationConfigSetterBasedDI() {
+        WebsiteControllerSetterInjection controllerwithSetterInjection = (WebsiteControllerSetterInjection) annotationContext.getBean("websiteControllerSetterInjection");
+        assertEquals(EXPECTED_STRING, controllerwithSetterInjection.getContentsViaSetterInjection());
+    }
+
+    @Test
+    public void testXMLConfigSetterBasedDI() {
+        WebsiteControllerSetterInjection controllerwithSetterInjection = (WebsiteControllerSetterInjection) xmlContext.getBean("websiteControllerSetterInjection");
+        assertEquals(EXPECTED_STRING, controllerwithSetterInjection.getContentsViaSetterInjection());
+    }
+
+}