Spring Data Injection Demo

Spring Data Injection Demo using annotations

SpringDataInjectionDemo/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<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>baeldung</groupId>
+	<artifactId>springdatainjectiondemo</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<packaging>jar</packaging>
+
+	<name>SpringDataInjectionDemo</name>
+	<description>Spring Data Injection Demp</description>
+
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>1.5.3.RELEASE</version>
+		<relativePath /> <!-- lookup parent from repository -->
+	</parent>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+		<java.version>1.8</java.version>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+			</plugin>
+		</plugins>
+	</build>
+
+
+</project>

SpringDataInjectionDemo/src/main/java/com/baeldung/SpringDataInjectionDemoApplication.java

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+package com.baeldung;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SpringDataInjectionDemoApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SpringDataInjectionDemoApplication.class, args);
+	}
+}

SpringDataInjectionDemo/src/main/java/com/baeldung/didemo/controller/OrderController.java

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+package com.baeldung.didemo.controller;
+
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.didemo.model.Order;
+import com.baeldung.didemo.service.CustomerServiceConstructorDI;
+import com.baeldung.didemo.service.CustomerServiceConstructorWithoutSpringDI;
+import com.baeldung.didemo.service.CustomerServiceFieldDI;
+import com.baeldung.didemo.service.CustomerServiceSetterDI;
+import com.baeldung.didemo.service.OrderService;
+
+@RestController
+@RequestMapping(value = "/orders")
+public class OrderController {
+
+    @Autowired
+    CustomerServiceConstructorDI constructorDI;
+
+    @Autowired
+    CustomerServiceFieldDI fieldDI;
+
+    @Autowired
+    CustomerServiceSetterDI setterDI;
+
+    @RequestMapping(method = RequestMethod.GET)
+    public List<Order> getOrdersFieldDI(@RequestParam(required = false) String dIMethod) {
+        if ("setter".equals(dIMethod)) {
+            return setterDI.getCustomerOrders(1l);
+        } else if ("constructor".equals(dIMethod)) {
+            return constructorDI.getCustomerOrders(1l);
+        } else if ("field".equals(dIMethod)) {
+            return fieldDI.getCustomerOrders(1l);
+        } else {
+            OrderService orderSvc = new OrderService();
+            CustomerServiceConstructorWithoutSpringDI customerSvc = new CustomerServiceConstructorWithoutSpringDI(orderSvc);
+            return customerSvc.getCustomerOrders(1l);
+        }
+    }
+}

SpringDataInjectionDemo/src/main/java/com/baeldung/didemo/model/Order.java

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+package com.baeldung.didemo.model;
+
+public class Order {
+
+    private Integer id;
+    private String item;
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public String getItem() {
+        return item;
+    }
+
+    public void setItem(String item) {
+        this.item = item;
+    }
+
+    // other order properties..
+
+}

SpringDataInjectionDemo/src/main/java/com/baeldung/didemo/service/CustomerServiceConstructorDI.java

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+package com.baeldung.didemo.service;
+
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import com.baeldung.didemo.model.Order;
+
+@Service
+public class CustomerServiceConstructorDI {
+
+    OrderService orderService;
+
+    @Autowired
+    public CustomerServiceConstructorDI(OrderService orderService) {
+        super();
+        this.orderService = orderService;
+    }
+
+    public List<Order> getCustomerOrders(Long customerId) {
+        return orderService.getOrdersForCustomer(customerId);
+    }
+
+}

SpringDataInjectionDemo/src/main/java/com/baeldung/didemo/service/CustomerServiceConstructorWithoutSpringDI.java

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+package com.baeldung.didemo.service;
+
+import java.util.List;
+
+import com.baeldung.didemo.model.Order;
+
+public class CustomerServiceConstructorWithoutSpringDI {
+
+    OrderService orderService;
+
+    public CustomerServiceConstructorWithoutSpringDI(OrderService orderService) {
+        super();
+        this.orderService = orderService;
+    }
+
+    public List<Order> getCustomerOrders(Long customerId) {
+        return orderService.getOrdersForCustomer(customerId);
+    }
+
+}

SpringDataInjectionDemo/src/main/java/com/baeldung/didemo/service/CustomerServiceFieldDI.java

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+package com.baeldung.didemo.service;
+
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import com.baeldung.didemo.model.Order;
+
+@Service
+public class CustomerServiceFieldDI {
+
+    @Autowired
+    OrderService orderService;
+    
+    public List<Order> getCustomerOrders(Long customerId) {
+        return orderService.getOrdersForCustomer(customerId);
+    }
+}

SpringDataInjectionDemo/src/main/java/com/baeldung/didemo/service/CustomerServiceSetterDI.java

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+package com.baeldung.didemo.service;
+
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import com.baeldung.didemo.model.Order;
+
+@Service
+public class CustomerServiceSetterDI {
+
+    OrderService orderService;
+
+    public List<Order> getCustomerOrders(Long customerId) {
+        return orderService.getOrdersForCustomer(customerId);
+    }
+
+    @Autowired
+    public void setOrderService(OrderService orderService) {
+        this.orderService = orderService;
+    }
+
+}

SpringDataInjectionDemo/src/main/java/com/baeldung/didemo/service/OrderService.java

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+package com.baeldung.didemo.service;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+
+import com.baeldung.didemo.model.Order;
+
+@Service
+public class OrderService {
+
+    public List<Order> getOrdersForCustomer(Long id) {
+        List<Order> orders = new ArrayList<Order>();
+        
+        Order order1 = new Order();
+        order1.setId(1);
+        order1.setItem("Pizza");
+        
+        Order order2 = new Order();
+        order2.setId(1);
+        order2.setItem("Garlic Bread");
+        
+        orders.add(order1);
+        orders.add(order2);
+        
+        return orders;
+    }
+    
+}