Add wanring log for the deprecated property

See gh-66

Author: kazuki43zoo

src/main/java/org/mybatis/scripting/velocity/VelocityLanguageDriverConfig.java

@@ -36,6 +36,8 @@
 
 import org.apache.commons.text.WordUtils;
 import org.apache.ibatis.io.Resources;
+import org.apache.ibatis.logging.Log;
+import org.apache.ibatis.logging.LogFactory;
 import org.apache.ibatis.reflection.DefaultReflectorFactory;
 import org.apache.ibatis.reflection.MetaObject;
 import org.apache.ibatis.reflection.factory.DefaultObjectFactory;
@@ -71,6 +73,8 @@ public class VelocityLanguageDriverConfig {
     TYPE_CONVERTERS = Collections.unmodifiableMap(converters);
   }
 
+  private static final Log log = LogFactory.getLog(VelocityLanguageDriverConfig.class);
+
   /**
    * The Velocity settings.
    */
@@ -123,6 +127,8 @@ public String[] getUserdirective() {
    */
   @Deprecated
   public void setUserdirective(String... userDirectives) {
+    log.warn(
+        "The 'userdirective' has been deprecated since 2.1.0. Please use the 'velocity-settings.runtime.custom_directives' or 'runtime.custom_directives'.");
     this.userDirectives = userDirectives;
   }
 
@@ -270,6 +276,9 @@ private static void override(VelocityLanguageDriverConfig config, Properties pro
   private static void enableLegacyAdditionalContextAttributes(Properties properties) {
     String additionalContextAttributes = properties.getProperty(PROPERTY_KEY_ADDITIONAL_CONTEXT_ATTRIBUTE);
     if (Objects.nonNull(additionalContextAttributes)) {
+      log.warn(String.format(
+          "The '%s' has been deprecated since 2.1.0. Please use the 'additionalContextAttributes.{name}={value}'.",
+          PROPERTY_KEY_ADDITIONAL_CONTEXT_ATTRIBUTE));
       Stream.of(additionalContextAttributes.split(",")).forEach(pair -> {
         String[] keyValue = pair.split(":");
         if (keyValue.length != 2) {

src/test/resources/log4j.properties

@@ -0,0 +1,26 @@
+#
+#    Copyright 2012-2019 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.
+#
+
+### Global logging configuration
+log4j.rootLogger=ERROR, stdout
+
+### Uncomment for MyBatis logging
+log4j.logger.org.mybatis.scripting.velocity=trace
+
+### Console output...
+log4j.appender.stdout=org.apache.log4j.ConsoleAppender
+log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
+log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n