Onboarding: Different Types of Bean Injection in Spring- Taylor Daugherty

spring-core/src/main/java/com/baeldung/dependencyinjectiontypes/UserConfig.java

@@ -0,0 +1,9 @@
+package com.baeldung.dependencyinjectiontypes;
+
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@ComponentScan
+public class UserConfig {
+}

spring-core/src/main/java/com/baeldung/dependencyinjectiontypes/UserDao.java

@@ -0,0 +1,15 @@
+package com.baeldung.dependencyinjectiontypes;
+
+import org.springframework.stereotype.Repository;
+
+import java.util.Arrays;
+import java.util.List;
+
+@Repository
+public class UserDao {
+
+    public List<String> getUsers() {
+        return Arrays.asList("John", "Sarah", "Mike");
+    }
+
+}

spring-core/src/main/java/com/baeldung/dependencyinjectiontypes/UserManager.java

@@ -0,0 +1,20 @@
+package com.baeldung.dependencyinjectiontypes;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class UserManager {
+
+    private UserDao userDao;
+
+    @Autowired
+    public UserManager(UserDao userDao) {
+        this.userDao = userDao;
+    }
+
+    public String getUsers() {
+        return String.join(", ", userDao.getUsers());
+    }
+
+}

spring-core/src/main/java/com/baeldung/dependencyinjectiontypes/UserService.java

@@ -0,0 +1,20 @@
+package com.baeldung.dependencyinjectiontypes;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+@Service
+public class UserService {
+
+    private UserDao userDao;
+
+    @Autowired
+    public void setUserDao(UserDao userDao) {
+        this.userDao = userDao;
+    }
+
+    public String getUsers() {
+        return String.join(", ", userDao.getUsers());
+    }
+
+}

spring-core/src/test/java/com/baeldung/dependencyinjectiontypes/UserDependencyInjectionTest.java

@@ -0,0 +1,25 @@
+package com.baeldung.dependencyinjectiontypes;
+
+import org.junit.Test;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+
+import static org.junit.Assert.assertEquals;
+
+public class UserDependencyInjectionTest {
+
+    @Test
+    public void whenUserServiceGetsUsers_thenUsersAreReturned() {
+        ApplicationContext context = new AnnotationConfigApplicationContext(UserConfig.class);
+        UserService userService = context.getBean(UserService.class);
+        assertEquals("John, Sarah, Mike", userService.getUsers());
+    }
+
+    @Test
+    public void whenUserManagerGetsUsers_thenUsersAreReturned() {
+        ApplicationContext context = new AnnotationConfigApplicationContext(UserConfig.class);
+        UserManager userManager = context.getBean(UserManager.class);
+        assertEquals("John, Sarah, Mike", userManager.getUsers());
+    }
+
+}