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

Author: philwebb

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 {
+
+	}
+
+}

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

@@ -49,6 +49,7 @@ public RelaxedConversionService(ConversionService conversionService) {
 		this.additionalConverters = new GenericConversionService();
 		this.additionalConverters
 				.addConverterFactory(new StringToEnumIgnoringCaseConverterFactory());
+		this.additionalConverters.addConverter(new StringToCharArrayConverter());
 	}
 
 	@Override

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

@@ -0,0 +1,33 @@
+/*
+ * 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.bind;
+
+import org.springframework.core.convert.converter.Converter;
+
+/**
+ * Converts a String to a Char Array.
+ *
+ * @author Phillip Webb
+ */
+class StringToCharArrayConverter implements Converter<String, char[]> {
+
+	@Override
+	public char[] convert(String source) {
+		return source.toCharArray();
+	}
+
+}

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

@@ -168,6 +168,16 @@ protected void onRefresh() throws BeansException {
 		assertTrue("No init", ConfigurationPropertiesWithFactoryBean.factoryBeanInit);
 	}
 
+	@Test
+	public void configurationPropertiesWithCharArray() throws Exception {
+		this.context = new AnnotationConfigApplicationContext();
+		EnvironmentTestUtils.addEnvironment(this.context, "test.chars:word");
+		this.context.register(PropertyWithCharArray.class);
+		this.context.refresh();
+		assertThat(this.context.getBean(PropertyWithCharArray.class).getChars(),
+				equalTo("word".toCharArray()));
+	}
+
 	@Configuration
 	@EnableConfigurationProperties
 	public static class TestConfigurationWithValidatingSetter {
@@ -282,6 +292,23 @@ public String getBar() {
 
 	}
 
+	@Configuration
+	@EnableConfigurationProperties
+	@ConfigurationProperties(prefix = "test")
+	public static class PropertyWithCharArray {
+
+		private char[] chars;
+
+		public char[] getChars() {
+			return this.chars;
+		}
+
+		public void setChars(char[] chars) {
+			this.chars = chars;
+		}
+
+	}
+
 	@Configuration
 	@EnableConfigurationProperties
 	@ConfigurationProperties(prefix = "test")