Only use PropertySource.getValue() as a fallback

It converts everything to a String so it isn't helpful to use
it as a default.

Fixes gh-2891.

spring-boot/src/main/java/org/springframework/boot/bind/PropertySourcesPropertyValues.java

@@ -121,12 +121,15 @@ public class PropertySourcesPropertyValues implements PropertyValues {
 						.contains(source.getName()) && !includes.matches(propertyName)) {
 					continue;
 				}
-				Object value = source.getProperty(propertyName);
+				Object value = null;
 				try {
-					value = resolver.getProperty(propertyName);
+					value = resolver.getProperty(propertyName, Object.class);
 				}
 				catch (RuntimeException ex) {
 					// Probably could not resolve placeholders, ignore it here
+					if (value == null) {
+						value = source.getProperty(propertyName);
+					}
 				}
 				if (!this.propertyValues.containsKey(propertyName)) {
 					this.propertyValues.put(propertyName, new PropertyValue(propertyName,

spring-boot/src/test/java/org/springframework/boot/bind/PropertySourcesPropertyValuesTests.java

@@ -57,6 +57,17 @@ public class PropertySourcesPropertyValuesTests {
 				.<String, Object> singletonMap("name", "${foo}")));
 	}
 
+	@Test
+	public void testTypesPreserved() {
+		this.propertySources.replace(
+				"map",
+				new MapPropertySource("map", Collections.<String, Object> singletonMap(
+						"name", 123)));
+		PropertySourcesPropertyValues propertyValues = new PropertySourcesPropertyValues(
+				this.propertySources);
+		assertEquals(123, propertyValues.getPropertyValues()[0].getValue());
+	}
+
 	@Test
 	public void testSize() {
 		PropertySourcesPropertyValues propertyValues = new PropertySourcesPropertyValues(