Close OutputStream after part created in PartGenerator

Closes gh-36945

spring-web/src/main/java/org/springframework/http/converter/multipart/PartGenerator.java

@@ -337,20 +337,15 @@ final class PartGenerator implements MultipartParser.PartListener {
 		public void onBody(DataBuffer dataBuffer, boolean last) {
 			this.byteCount += dataBuffer.readableByteCount();
 			if (isMaxDiskUsagePerPartExceeded()) {
-				try {
-					this.outputStream.close();
-				}
-				catch (IOException exc) {
-					// ignored
-				}
-				throw new HttpMessageConversionException(
-						"Part exceeded the disk usage limit of " +
-								PartGenerator.this.maxDiskUsagePerPart + " bytes");
+				closeOutputStream();
+				throw new HttpMessageConversionException("Part exceeded " +
+						"the disk usage limit of " + PartGenerator.this.maxDiskUsagePerPart + " bytes");
 			}
 			writeBuffer(dataBuffer);
 			if (last) {
 				Part part = DefaultParts.part(this.headers, this.file);
 				PartGenerator.this.addPart(part);
+				closeOutputStream();
 			}
 		}
 
@@ -359,6 +354,15 @@ final class PartGenerator implements MultipartParser.PartListener {
 					this.byteCount > PartGenerator.this.maxDiskUsagePerPart);
 		}
 
+		private void closeOutputStream() {
+			try {
+				this.outputStream.close();
+			}
+			catch (IOException exc) {
+				// ignored
+			}
+		}
+
 		private Path createFile(Path directory) {
 			try {
 				Path tempFile = Files.createTempFile(directory, null, ".multipart");