Support String to char[] bindings

Update RelaxedConversionService to also support String to char[]
conversion. Primarily to support the `password` field in
MongoProperties.

Fixes gh-1572

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mongo/MongoPropertiesTests.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.autoconfigure.mongo;
+
+import org.junit.Test;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.test.EnvironmentTestUtils;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Configuration;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Tests for {@link MongoProperties}.
+ *
+ * @author Phillip Webb
+ */
+public class MongoPropertiesTests {
+
+	@Test
+	public void canBindCharArrayPassword() {
+		// gh-1572
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		EnvironmentTestUtils.addEnvironment(context, "spring.data.mongodb.password:word");
+		context.register(Conf.class);
+		context.refresh();
+		MongoProperties properties = context.getBean(MongoProperties.class);
+		assertThat(properties.getPassword(), equalTo("word".toCharArray()));
+	}
+
+	@Configuration
+	@EnableConfigurationProperties(MongoProperties.class)
+	static class Conf {
+
+	}
+
+}