adding StringSerDe helper class for NiFi utils package.

nifi-sumo-common/src/main/java/com/crossbusiness/nifi/processors/StringSerDe.java

@@ -0,0 +1,28 @@
+package com.crossbusiness.nifi.processors;
+
+import org.apache.nifi.distributed.cache.client.Deserializer;
+import org.apache.nifi.distributed.cache.client.Serializer;
+import org.apache.nifi.distributed.cache.client.exception.DeserializationException;
+import org.apache.nifi.distributed.cache.client.exception.SerializationException;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+
+public class StringSerDe implements Serializer<String>, Deserializer<String> {
+
+    @Override
+    public String deserialize(final byte[] value) throws DeserializationException, IOException {
+        if (value == null) {
+            return null;
+        }
+
+        return new String(value, StandardCharsets.UTF_8);
+    }
+
+    @Override
+    public void serialize(final String value, final OutputStream out) throws SerializationException, IOException {
+        out.write(value.getBytes(StandardCharsets.UTF_8));
+    }
+
+}