Fix Invalid target for Validator error

Update `PropertiesConfigurationFactory` so that the validator is only
set when it supports the target object.

Fixes gh-8149

Author: philwebb

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

@@ -253,7 +253,8 @@ private void doBindPropertiesToTarget() throws BindException {
 		RelaxedDataBinder dataBinder = (this.targetName != null
 				? new RelaxedDataBinder(this.target, this.targetName)
 				: new RelaxedDataBinder(this.target));
-		if (this.validator != null) {
+		if (this.validator != null
+				&& this.validator.supports(dataBinder.getTarget().getClass())) {
 			dataBinder.setValidator(this.validator);
 		}
 		if (this.conversionService != null) {

spring-boot/src/test/java/org/springframework/boot/context/properties/ConfigurationPropertiesBindingPostProcessorTests.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.context.properties;
 
 import java.util.List;
+import java.util.Map;
 
 import javax.annotation.PostConstruct;
 import javax.validation.constraints.NotNull;
@@ -47,6 +48,7 @@
 import org.springframework.validation.ValidationUtils;
 import org.springframework.validation.Validator;
 import org.springframework.validation.annotation.Validated;
+import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.Assert.fail;
@@ -330,6 +332,17 @@ public void multiplePropertySourcesPlaceholderConfigurer() throws Exception {
 				"Multiple PropertySourcesPlaceholderConfigurer beans registered");
 	}
 
+	@Test
+	public void propertiesWithMap() throws Exception {
+		this.context = new AnnotationConfigApplicationContext();
+		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(this.context,
+				"test.map.foo=bar");
+		this.context.register(PropertiesWithMap.class);
+		this.context.refresh();
+		assertThat(this.context.getBean(PropertiesWithMap.class).getMap())
+				.containsEntry("foo", "bar");
+	}
+
 	private void assertBindingFailure(int errorCount) {
 		try {
 			this.context.refresh();
@@ -608,6 +621,28 @@ public static PropertySourcesPlaceholderConfigurer configurer() {
 
 	}
 
+	@Configuration
+	@EnableConfigurationProperties
+	@ConfigurationProperties(prefix = "test")
+	public static class PropertiesWithMap {
+
+		@Bean
+		public Validator validator() {
+			return new LocalValidatorFactoryBean();
+		}
+
+		private Map<String, String> map;
+
+		public Map<String, String> getMap() {
+			return this.map;
+		}
+
+		public void setMap(Map<String, String> map) {
+			this.map = map;
+		}
+
+	}
+
 	@Configuration
 	@EnableConfigurationProperties
 	public static class ConfigurationPropertiesWithFactoryBean {