src/main/java/org/embulk/output/mailchimp/MailChimpAbstractRecordBuffer.java in embulk-output-mailchimp-0.3.3 vs src/main/java/org/embulk/output/mailchimp/MailChimpAbstractRecordBuffer.java in embulk-output-mailchimp-0.3.4

@@ -32,10 +32,11 @@
 
 import static org.embulk.output.mailchimp.helper.MailChimpHelper.containsCaseInsensitive;
 import static org.embulk.output.mailchimp.helper.MailChimpHelper.fromCommaSeparatedString;
 import static org.embulk.output.mailchimp.model.MemberStatus.PENDING;
 import static org.embulk.output.mailchimp.model.MemberStatus.SUBSCRIBED;
+import static org.embulk.spi.type.Types.JSON;
 
 /**
  * Created by thangnc on 4/14/17.
  */
 public abstract class MailChimpAbstractRecordBuffer
@@ -270,11 +271,16 @@
 
                 // Update additional merge fields if exist
                 if (task.getMergeFields().isPresent() && !task.getMergeFields().get().isEmpty()) {
                     for (final Column column : schema.getColumns()) {
                         if (!"".equals(containsCaseInsensitive(column.getName(), task.getMergeFields().get()))) {
-                            String value = input.findValue(column.getName()).asText();
-                            mergeFields.put(column.getName().toUpperCase(), value);
+                            if (column.getType().equals(JSON)) {
+                                mergeFields.set(column.getName().toUpperCase(), input.findValue(column.getName()));
+                            }
+                            else {
+                                String value = input.findValue(column.getName()).asText();
+                                mergeFields.put(column.getName().toUpperCase(), value);
+                            }
                         }
                     }
                 }
 
                 property.set("merge_fields", mergeFields);