use property placeholder in SpringFramework MessageSource

env.properties

xday=2011/07/02

Message.java

package sandbox.message;

import java.util.Locale;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.MessageSource;
import org.springframework.stereotype.Service;

@Service
public class Message {

    @Autowired
    MessageSource messageSource;

    public String showHello() {
        return messageSource.getMessage("hello", null, Locale.getDefault());
    }
}

messages.properties

hello=こんにちは。Xデーは ${xday} です

MessageTest-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:util="http://www.springframework.org/schema/util"
	xsi:schemaLocation="
	   http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
	   http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
	   http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
	   http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd">

	<context:component-scan base-package="sandbox.message" />

	<bean id="placeholderProperties"
		class="org.springframework.beans.factory.config.PropertiesFactoryBean">
		<property name="location" value="classpath:sandbox/message/env.properties" />
		<property name="fileEncoding" value="utf-8" />
	</bean>

	<bean id="messageSource"
		class="sandbox.message.PlaceHolderConfigurableReloadableResourceBundleMessageSource">
		<property name="basename" value="classpath:sandbox/message/messages" />
		<property name="defaultEncoding" value="utf-8" />
		<property name="placeholderProperties" ref="placeholderProperties" />
	</bean>
</beans>

MessageTest.java

package sandbox.message;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@ContextConfiguration
@RunWith(SpringJUnit4ClassRunner.class)
public class MessageTest {

    @Autowired
    Message message;

    @Test
    public void testShowHello() {
        System.out.println(message.showHello());
    }
}

ReloadableResourceBundleMessageSource.java.patch

--- ReloadableResourceBundleMessageSource.java	2011-07-02 16:34:17.421875000 +0900
+++ PlaceholderConfigurableReloadableResourceBundleMessageSource.java	2011-07-02 18:02:31.734375000 +0900
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.context.support;
+package sandbox.message;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -27,13 +27,17 @@
 import java.util.Map;
 import java.util.Properties;
 
+import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
 import org.springframework.context.ResourceLoaderAware;
+import org.springframework.context.support.AbstractMessageSource;
+import org.springframework.context.support.ResourceBundleMessageSource;
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.util.Assert;
 import org.springframework.util.DefaultPropertiesPersister;
 import org.springframework.util.PropertiesPersister;
+import org.springframework.util.PropertyPlaceholderHelper;
 import org.springframework.util.StringUtils;
 
 /**
@@ -88,7 +92,7 @@
  * @see ResourceBundleMessageSource
  * @see java.util.ResourceBundle
  */
-public class ReloadableResourceBundleMessageSource extends AbstractMessageSource
+public class PlaceHolderConfigurableReloadableResourceBundleMessageSource extends AbstractMessageSource
 		implements ResourceLoaderAware {
 
 	private static final String PROPERTIES_SUFFIX = ".properties";
@@ -571,8 +575,8 @@
 	 */
 	public void clearCacheIncludingAncestors() {
 		clearCache();
-		if (getParentMessageSource() instanceof ReloadableResourceBundleMessageSource) {
-			((ReloadableResourceBundleMessageSource) getParentMessageSource()).clearCacheIncludingAncestors();
+		if (getParentMessageSource() instanceof PlaceHolderConfigurableReloadableResourceBundleMessageSource) {
+			((PlaceHolderConfigurableReloadableResourceBundleMessageSource) getParentMessageSource()).clearCacheIncludingAncestors();
 		}
 	}
 
@@ -583,6 +587,17 @@
 	}
 
 
+	private PropertyPlaceholderHelper placeholderHelper = new PropertyPlaceholderHelper(
+			PropertyPlaceholderConfigurer.DEFAULT_PLACEHOLDER_PREFIX,
+			PropertyPlaceholderConfigurer.DEFAULT_PLACEHOLDER_SUFFIX,
+			PropertyPlaceholderConfigurer.DEFAULT_VALUE_SEPARATOR, true);
+
+	private Properties placeholderProperties;
+
+	public void setPlaceholderProperties(Properties placeholderProperties) {
+		this.placeholderProperties = placeholderProperties;
+	}
+	
 	/**
 	 * PropertiesHolder for caching.
 	 * Stores the last-modified timestamp of the source file for efficient
@@ -629,7 +644,8 @@
 			if (this.properties == null) {
 				return null;
 			}
-			return this.properties.getProperty(code);
+			String value = this.properties.getProperty(code);
+			return placeholderHelper.replacePlaceholders(value, placeholderProperties);
 		}
 
 		public MessageFormat getMessageFormat(String code, Locale locale) {