added .this to selectMap new methods

Author: emacarron

src/main/java/org/mybatis/spring/SqlSessionTemplate.java

@@ -161,21 +161,21 @@ public Object selectOne(String statement, Object parameter) {
      * {@inheritDoc}
      */
     public Map<?, ?> selectMap(String statement, String mapKey) {
-        return sqlSessionProxy.selectMap(statement, mapKey);
+        return this.sqlSessionProxy.selectMap(statement, mapKey);
     }
 
     /**
      * {@inheritDoc}
      */
     public Map<?, ?> selectMap(String statement, Object parameter, String mapKey) {
-        return sqlSessionProxy.selectMap(statement, parameter, mapKey);
+        return this.sqlSessionProxy.selectMap(statement, parameter, mapKey);
     }
 
     /**
      * {@inheritDoc}
      */
     public Map<?, ?> selectMap(String statement, Object parameter, String mapKey, RowBounds rowBounds) {
-        return sqlSessionProxy.selectMap(statement, parameter, mapKey, rowBounds);
+        return this.sqlSessionProxy.selectMap(statement, parameter, mapKey, rowBounds);
     }
 
     /**