spring Inject a Property Value Into a Class Not Managed by Spring

Author: peijd

spring-properties/src/main/java/com/ripjava/spring/properties/properties/ClassNotManagedBySpring.java

@@ -0,0 +1,28 @@
+package com.ripjava.spring.properties.properties;
+
+public class ClassNotManagedBySpring {
+
+    private String customVariable;
+    private String anotherCustomVariable;
+
+    public ClassNotManagedBySpring(String someInitialValue, String anotherManagedValue) {
+        this.customVariable = someInitialValue;
+        this.anotherCustomVariable = anotherManagedValue;
+    }
+
+    public String getCustomVariable() {
+        return customVariable;
+    }
+
+    public void setCustomVariable(String customVariable) {
+        this.customVariable = customVariable;
+    }
+
+    public String getAnotherCustomVariable() {
+        return anotherCustomVariable;
+    }
+
+    public void setAnotherCustomVariable(String anotherCustomVariable) {
+        this.anotherCustomVariable = anotherCustomVariable;
+    }
+}

spring-properties/src/main/java/com/ripjava/spring/properties/properties/InitializerBean.java

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+package com.ripjava.spring.properties.properties;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+
+@Component
+public class InitializerBean {
+
+    private String someInitialValue;
+    private String anotherManagedValue;
+
+    public InitializerBean(@Value("someInitialValue") String someInitialValue, @Value("anotherValue") String anotherManagedValue) {
+        this.someInitialValue = someInitialValue;
+        this.anotherManagedValue = anotherManagedValue;
+    }
+
+    public ClassNotManagedBySpring initClass() {
+        return new ClassNotManagedBySpring(this.someInitialValue, this.anotherManagedValue);
+    }
+
+}

spring-properties/src/main/java/com/ripjava/spring/properties/properties/PropertiesLoader.java

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+package com.ripjava.spring.properties.properties;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Properties;
+
+public class PropertiesLoader {
+
+    public static Properties loadProperties(String resourceFileName) throws IOException {
+        Properties configuration = new Properties();
+        InputStream inputStream = PropertiesLoader.class
+                .getClassLoader()
+                .getResourceAsStream(resourceFileName);
+        configuration.load(inputStream);
+        inputStream.close();
+        return configuration;
+    }
+
+}

spring-properties/src/main/resources/configuration.properties

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+# this is sample property file for PropertiesLoaderTest configuration needs
+! this is also a comment
+sampleConfEntry = sample String value
+colonSeparatedEntry : colon separated entry value

spring-properties/src/test/java/com/ripjava/spring/properties/properties/ClassNotManagedBySpringIntegrationTest.java

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+package com.ripjava.spring.properties.properties;
+
+
+import com.ripjava.spring.properties.ConfigPropertiesDemoApplication;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(SpringExtension.class)
+public class ClassNotManagedBySpringIntegrationTest {
+
+
+    @MockBean
+    private InitializerBean initializerBean;
+
+    @BeforeEach
+    public void init() {
+        when(initializerBean.initClass())
+                .thenReturn(new ClassNotManagedBySpring("This is only sample value", "Another configured value"));
+    }
+    @Test
+    public void test_ClassNotManagedBySpring(){
+        ClassNotManagedBySpring classNotManagedBySpring = initializerBean.initClass();
+
+        String initializedValue = classNotManagedBySpring.getCustomVariable();
+        String anotherCustomVariable = classNotManagedBySpring.getAnotherCustomVariable();
+
+        assertEquals("This is only sample value", initializedValue);
+        assertEquals("Another configured value", anotherCustomVariable);
+    }
+
+}

spring-properties/src/test/java/com/ripjava/spring/properties/properties/PropertiesLoaderUnitTest.java

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+package com.ripjava.spring.properties.properties;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.util.Properties;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class PropertiesLoaderUnitTest {
+
+    @Test
+    public void test_loadProperties() throws IOException {
+        final String RESOURCE_FILE_NAME = "configuration.properties";
+
+        final String SAMPLE_CONF_ENTRY = "sampleConfEntry";
+        final String COLON_SEPARATED_CONF_ENTRY = "colonSeparatedEntry";
+
+        final String GIVEN_CONF_ENTRY_VALUE = "sample String value";
+        final String COLON_SEPARATED_CONF_ENTRY_VALUE = "colon separated entry value";
+
+        Properties config = PropertiesLoader.loadProperties(RESOURCE_FILE_NAME);
+        String sampleConfEntryValue = config.getProperty(SAMPLE_CONF_ENTRY);
+        String colonSeparatedConfEntryValue = config.getProperty(COLON_SEPARATED_CONF_ENTRY);
+
+        assertEquals(GIVEN_CONF_ENTRY_VALUE, sampleConfEntryValue);
+        assertEquals(COLON_SEPARATED_CONF_ENTRY_VALUE, colonSeparatedConfEntryValue);
+
+    }
+}