only try to cache chunk manifest chunks

other/java/client/src/main/java/seaweedfs/client/FileChunkManifest.java

@@ -76,8 +76,11 @@ public class FileChunkManifest {
             LOG.debug("doFetchFullChunkData:{}", chunkView);
             chunkData = SeaweedRead.doFetchFullChunkData(chunkView, locations);
         }
+        if（chunk.getIsChunkManifest()){
+            // only cache manifest chunks
             LOG.debug("chunk {} size {}", chunkView.fileId, chunkData.length);
             SeaweedRead.chunkCache.setChunk(chunkView.fileId, chunkData);
+        }
 
         return chunkData;