PartGenerator disposes of resources in current State

Closes gh-36942

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

@@ -112,16 +112,17 @@ final class PartGenerator implements MultipartParser.PartListener {
 	}
 
 	void deleteParts() {
-		try {
-			for (List<Part> partList : this.parts.values()) {
-				for (Part part : partList) {
+		this.state.dispose();
+		for (List<Part> parts : this.parts.values()) {
+			for (Part part : parts) {
+				try {
 					part.delete();
 				}
+				catch (IOException ex) {
+					// ignored
+				}
 			}
 		}
-		catch (IOException ex) {
-			// ignored
-		}
 	}
 
 	@Override
@@ -170,6 +171,12 @@ final class PartGenerator implements MultipartParser.PartListener {
 		 */
 		void onBody(DataBuffer dataBuffer, boolean last);
 
+		/**
+		 * Clean up resources.
+		 */
+		default void dispose() {
+		}
+
 	}
 
 	/**
@@ -305,6 +312,11 @@ final class PartGenerator implements MultipartParser.PartListener {
 			PartGenerator.this.addPart(part);
 		}
 
+		@Override
+		public void dispose() {
+			this.content.forEach(DataBufferUtils::release);
+		}
+
 		@Override
 		public String toString() {
 			return "IN-MEMORY";
@@ -398,6 +410,17 @@ final class PartGenerator implements MultipartParser.PartListener {
 			}
 		}
 
+		@Override
+		public void dispose() {
+			closeOutputStream();
+			try {
+				Files.deleteIfExists(this.file);
+			}
+			catch (IOException ex) {
+				// ignored
+			}
+		}
+
 		@Override
 		public String toString() {
 			return "WRITE-FILE";