src/main/java/com/example/demo/service/TransactionService.java

@@ -0,0 +1,11 @@
+package com.example.demo.service;
+
+import org.springframework.stereotype.Service;
+import com.example.demo.dto.TransactionDTO;
+
+@Service
+public class TransactionService {
+    public void processTransaction(TransactionDTO transactionDTO) {
+        // 거래 처리 로직
+    }
+}