injecting beans

injecting-beans/pom.xml

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+<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/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.baeldung.common</groupId>
+  <artifactId>SpringExample</artifactId>
+  <packaging>jar</packaging>
+  <version>1.0-SNAPSHOT</version>
+  <name>SpringExample</name>
+  <url>http://maven.apache.org</url>
+  
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.12</version>
+      <scope>test</scope>
+    </dependency>
+    
+    <!-- Spring framework -->
+      <dependency>
+          <groupId>org.springframework</groupId>
+          <artifactId>spring-core</artifactId>
+          <version>4.1.4.RELEASE</version>
+      </dependency>
+      <dependency>
+          <groupId>org.springframework</groupId>
+          <artifactId>spring-context</artifactId>
+          <version>4.1.4.RELEASE</version>
+      </dependency>
+
+  </dependencies>
+</project>

injecting-beans/src/main/java/com/baeldung/App.java

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+package com.baeldung;
+
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.support.ClassPathXmlApplicationContext;
+
+/**
+ * Application presenting various possibilities of bean injections in Spring.
+ */
+public class App {
+    public static void main(String[] args) {
+        ApplicationContext context = new ClassPathXmlApplicationContext("Spring-Module.xml");
+
+        Computer obj = (Computer) context.getBean("computer");
+        obj.print();
+    }
+}

injecting-beans/src/main/java/com/baeldung/Computer.java

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+package com.baeldung;
+
+import com.baeldung.model.*;
+import org.springframework.beans.factory.annotation.Autowired;
+
+/**
+ * Model for Computer.
+ */
+public class Computer {
+
+    @Autowired
+    private GraphicsCard graphicsCard;
+    private Processor processor;
+    private HardDisk hardDisk;
+    private Screen screen;
+    private OperatingSystem operatingSystem;
+
+    public Computer(Processor processor) {
+        this.processor = processor;
+    }
+
+    @Autowired
+    public Computer(OperatingSystem operatingSystem, Processor processor) {
+        this.operatingSystem = operatingSystem;
+        this.processor = processor;
+    }
+
+    public void setHardDisk(HardDisk hardDisk) {
+        this.hardDisk = hardDisk;
+    }
+
+    @Autowired
+    public void setScreen(Screen screen) {
+        this.screen = screen;
+    }
+
+    public void print() {
+        System.out.println("Injected processor by constructor injection: " + processor.getName());
+        System.out.println("Injected hard disk by setter injection: " + hardDisk.getName());
+        System.out.println("Injected graphics card with field annotation: " + graphicsCard.getName());
+        System.out.println("Injected screen with setter annotation: " + screen.getSize());
+        System.out.println("Injected operating system name with constructor annotation: " + operatingSystem.getName());
+    }
+
+    @Override
+    public String toString() {
+        return "Computer{" +
+                "graphicsCard=" + graphicsCard +
+                ", processor=" + processor +
+                ", hardDisk=" + hardDisk +
+                ", screen=" + screen +
+                ", operatingSystem=" + operatingSystem +
+                '}';
+    }
+}

injecting-beans/src/main/java/com/baeldung/model/GraphicsCard.java

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+package com.baeldung.model;
+
+/**
+ * Model for graphics card.
+ */
+public class GraphicsCard {
+    String name;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public String toString() {
+        return "GraphicsCard{" +
+                "name='" + name + '\'' +
+                '}';
+    }
+}

injecting-beans/src/main/java/com/baeldung/model/HardDisk.java

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+package com.baeldung.model;
+
+/**
+ * Model for hard disk drive.
+ */
+public class HardDisk {
+    private String name;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public String toString() {
+        return "HardDisk{" +
+                "name='" + name + '\'' +
+                '}';
+    }
+}

injecting-beans/src/main/java/com/baeldung/model/OperatingSystem.java

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+package com.baeldung.model;
+
+/**
+ * Model for operating system.
+ */
+public class OperatingSystem {
+    private String name;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public String toString() {
+        return "OperatingSystem{" +
+                "name='" + name + '\'' +
+                '}';
+    }
+}

injecting-beans/src/main/java/com/baeldung/model/Processor.java

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+package com.baeldung.model;
+
+/**
+ * Model for Processor.
+ */
+public class Processor {
+    private String name;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public String toString() {
+        return "Processor{" +
+                "name='" + name + '\'' +
+                '}';
+    }
+}

injecting-beans/src/main/java/com/baeldung/model/Screen.java

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+package com.baeldung.model;
+
+/**
+ * Model for Screen.
+ */
+public class Screen {
+
+    private String size;
+
+    public String getSize() {
+        return size;
+    }
+
+    public void setSize(String size) {
+        this.size = size;
+    }
+
+    @Override
+    public String toString() {
+        return "Screen{" +
+                "size='" + size + '\'' +
+                '}';
+    }
+}

injecting-beans/src/main/resources/Spring-Module.xml

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+<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-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
+
+    <bean id="computer" class="com.baeldung.Computer">
+        <constructor-arg>
+            <ref bean="processor"/>
+        </constructor-arg>
+        <property name="hardDisk">
+            <ref bean="hardDisk"/>
+        </property>
+    </bean>
+
+    <bean id="processor" class="com.baeldung.model.Processor">
+        <property name="name" value="Intel Core i7-6650U"/>
+    </bean>
+
+    <bean id="hardDisk" class="com.baeldung.model.HardDisk">
+        <property name="name" value="SSD TRANSCEND MTS400"/>
+    </bean>
+
+    <bean id="graphicsCard" class="com.baeldung.model.GraphicsCard">
+        <property name="name" value="NVIDIA GeForce GTX980M"/>
+    </bean>
+
+    <bean id="screen" class="com.baeldung.model.Screen">
+        <property name="size" value="17 inches"/>
+    </bean>
+
+    <bean id="operatingSystem" class="com.baeldung.model.OperatingSystem">
+        <property name="name" value="Windows 10 Pro"/>
+    </bean>
+
+    <context:annotation-config/>
+</beans>