revise XATransactionService.

sharding-jdbc-example/transaction-example/transaction-2pc-xa-example/transaction-xa-spring-boot-example/src/main/java/io/shardingsphere/example/transaction/xa/spring/boot/XATransactionalService.java

@@ -51,4 +51,8 @@ public class XATransactionalService {
     public void processFailure() {
         jpaCommonService.processFailure();
     }
+    
+    public void printData() {
+        jpaCommonService.printData();
+    }
 }