BAEL-4069: Add example of using @Value with constructor/setter (#9318)

spring-boot-modules/spring-boot-properties/src/main/java/com/baeldung/value/CollectionProvider.java

@@ -0,0 +1,27 @@
+package com.baeldung.value;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.PropertySource;
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+@Component
+@PropertySource("classpath:values.properties")
+public class CollectionProvider {
+
+    private final List<String> values = new ArrayList<>();
+
+    public Collection<String> getValues() {
+        return Collections.unmodifiableCollection(values);
+    }
+
+    @Autowired
+    public void setValues(@Value("#{'${listOfValues}'.split(',')}") List<String> values) {
+        this.values.addAll(values);
+    }
+}

spring-boot-modules/spring-boot-properties/src/main/java/com/baeldung/value/PriorityProvider.java

@@ -0,0 +1,22 @@
+package com.baeldung.value;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.PropertySource;
+import org.springframework.stereotype.Component;
+
+@Component
+@PropertySource("classpath:values.properties")
+public class PriorityProvider {
+
+    private final String priority;
+
+    @Autowired
+    public PriorityProvider(@Value("${priority:normal}") String priority) {
+        this.priority = priority;
+    }
+
+    public String getPriority() {
+        return priority;
+    }
+}

spring-boot-modules/spring-boot-properties/src/main/resources/values.properties

@@ -1,4 +1,4 @@
 value.from.file=Value got from the file
-priority=Properties file
+priority=high
 listOfValues=A,B,C
 valuesMap={key1:'1', key2 : '2', key3 : '3'}

spring-boot-modules/spring-boot-properties/src/test/java/com/baeldung/value/CollectionProviderIntegrationTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.value;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = CollectionProvider.class)
+public class CollectionProviderIntegrationTest {
+
+    @Autowired
+    private CollectionProvider collectionProvider;
+
+    @Test
+    public void givenPropertyFileWhenSetterInjectionUsedThenValueInjected() {
+        assertThat(collectionProvider.getValues()).contains("A", "B", "C");
+    }
+}

spring-boot-modules/spring-boot-properties/src/test/java/com/baeldung/value/PriorityProviderIntegrationTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.value;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = PriorityProvider.class)
+public class PriorityProviderIntegrationTest {
+
+    @Autowired
+    private PriorityProvider priorityProvider;
+
+    @Test
+    public void givenPropertyFileWhenConstructorInjectionUsedThenValueInjected() {
+        assertThat(priorityProvider.getPriority()).isEqualTo("Properties file");
+    }
+}