[EDIT] EntityからModelへの変換メソッドを作成しました。

src/main/java/com/example/demo/app/domain/model/TransactionModel.java

@@ -1,6 +1,9 @@
 package com.example.demo.app.domain.model;
 
 import java.time.LocalDate;
+import java.util.List;
+
+import com.example.demo.app.infra.entity.TransactionEntity;
 
 import lombok.AllArgsConstructor;
 import lombok.Getter;
@@ -19,4 +22,17 @@ public class TransactionModel {
 	
 	private LocalDate transactionDate;
 	
+	public static TransactionModel convertFrom(TransactionEntity transactionEntity) {
+		return new TransactionModel(
+				transactionEntity.getTransactionId(),
+				transactionEntity.getUserEntity().getUserId(),
+				transactionEntity.getCategoryEntity().getCategoryId(),
+				transactionEntity.getAmount(),
+				transactionEntity.getTransactionDate());
+	}
+
+	public static List<TransactionModel> convertFrom(List<TransactionEntity> transactionEntityList) {
+		return transactionEntityList.stream().map(TransactionModel::convertFrom).toList();
+	}
+	
 }