HOTFIX: 납부자 엑셀 파일 깨지는 현상 수정

Author: tnals0924

src/main/kotlin/site/billilge/api/backend/domain/payer/controller/AdminPayerApi.kt

@@ -1,9 +1,12 @@
 package site.billilge.api.backend.domain.payer.controller
 
 import io.swagger.v3.oas.annotations.Operation
+import io.swagger.v3.oas.annotations.media.Content
+import io.swagger.v3.oas.annotations.media.Schema
 import io.swagger.v3.oas.annotations.responses.ApiResponse
 import io.swagger.v3.oas.annotations.responses.ApiResponses
 import io.swagger.v3.oas.annotations.tags.Tag
+import org.springframework.core.io.InputStreamResource
 import org.springframework.http.ResponseEntity
 import org.springframework.web.bind.annotation.RequestBody
 import org.springframework.web.bind.annotation.RequestParam
@@ -62,4 +65,22 @@ interface AdminPayerApi {
         ]
     )
     fun deletePayers(@RequestBody request: PayerDeleteRequest): ResponseEntity<Void>
+
+    @Operation(
+        summary = "학생회비 납부자 Excel 파일 다운로드",
+        description = "학생회비 납부자 데이터를 엑셀 파일로 다운받을 수 있는 관리자용 API"
+    )
+    @ApiResponses(
+        value = [
+            ApiResponse(
+                responseCode = "200",
+                description = "파일 다운로드 성공",
+                content = [Content(
+                    mediaType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+                    schema = Schema(type = "string", format = "binary")
+                )]
+            )
+        ]
+    )
+    fun createPayerExcel(): ResponseEntity<InputStreamResource>
 }

src/main/kotlin/site/billilge/api/backend/domain/payer/controller/AdminPayerController.kt

@@ -3,6 +3,7 @@ package site.billilge.api.backend.domain.payer.controller
 import org.springframework.core.io.InputStreamResource
 import org.springframework.http.ContentDisposition
 import org.springframework.http.HttpHeaders
+import org.springframework.http.MediaType
 import org.springframework.http.ResponseEntity
 import org.springframework.web.bind.annotation.*
 import site.billilge.api.backend.domain.payer.dto.request.PayerDeleteRequest
@@ -42,7 +43,7 @@ class AdminPayerController(
     }
 
     @GetMapping("/excel")
-    fun createPayerExcel(): ResponseEntity<InputStreamResource> {
+    override fun createPayerExcel(): ResponseEntity<InputStreamResource> {
         val excel = payerService.createPayerExcel()
         val currentDate = LocalDate.now()
         val dateFormatter = DateTimeFormatter.ofPattern("yyyyMMdd")
@@ -51,9 +52,11 @@ class AdminPayerController(
                 .filename("kmusw_payers_${dateFormatter.format(currentDate)}.xlsx")
                 .build()
         }
+        val excelMediaType = MediaType.valueOf("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
 
         return ResponseEntity.ok()
             .headers(headers)
+            .contentType(excelMediaType)
             .body(InputStreamResource((excel)))
     }
 }

src/main/kotlin/site/billilge/api/backend/global/utils/ExcelGenerator.kt

@@ -17,18 +17,21 @@ class ExcelGenerator {
     ): ByteArrayInputStream {
         val workbook = SXSSFWorkbook()
 
-        sheetData.forEach { (sheetName, sheetContent) ->
-            val (headerTitles, rows) = sheetContent
-            val sheet = workbook.createSheet(sheetName)
-            styleHeaders(workbook, sheet, headerTitles)
-            fillData(sheet, rows, headerTitles.size)
-        }
-
-        val out = ByteArrayOutputStream()
-        workbook.write(out)
-        workbook.close()
+        try {
+            sheetData.forEach { (sheetName, sheetContent) ->
+                val (headerTitles, rows) = sheetContent
+                val sheet = workbook.createSheet(sheetName)
+                styleHeaders(workbook, sheet, headerTitles)
+                fillData(sheet, rows, headerTitles.size)
+            }
 
-        return ByteArrayInputStream(out.toByteArray())
+            val out = ByteArrayOutputStream()
+            workbook.write(out)
+            return ByteArrayInputStream(out.toByteArray())
+        } finally {
+            workbook.dispose()
+            workbook.close()
+        }
     }
 
     private fun styleHeaders(workbook: SXSSFWorkbook, sheet: SXSSFSheet, headerTitles: Array<String>) {