diff --git a/src/main/java/w2phtml/rdf/Metadata.java b/src/main/java/w2phtml/rdf/Metadata.java
index 20a6d3d..27b63b7 100644
--- a/src/main/java/w2phtml/rdf/Metadata.java
+++ b/src/main/java/w2phtml/rdf/Metadata.java
@@ -23,8 +23,11 @@ public class Metadata {
 	}
 
 	public void read(String metadataFilePath) {
+		if (metadataFilePath == null) {
+			return;
+		}
 		File file = new File(metadataFilePath);
-		if (!file.exists()) {
+		if (!file.exists() || !file.canRead()) {
 			return;
 		}
 	  readCSVFile(metadataFilePath);