Call hstrlen on JedisCluster.

We now call hstrlen on the Cluster client instead of using our execute(…) fallback and determining the correct cluster node ourselves.

Closes #2392

src/main/java/org/springframework/data/redis/connection/RedisHashCommands.java

@@ -237,13 +237,14 @@ public interface RedisHashCommands {
 	Cursor<Map.Entry<byte[], byte[]>> hScan(byte[] key, ScanOptions options);
 
 	/**
-	 * Returns the length of the value associated with {@code field} in the hash stored at {@code key}. If the key or the
-	 * field do not exist, {@code 0} is returned.
+	 * Returns the length of the value associated with {@code field} in the hash stored at {@code key}. If the {@code key}
+	 * or the {@code field} do not exist, {@code 0} is returned.
 	 *
 	 * @param key must not be {@literal null}.
 	 * @param field must not be {@literal null}.
 	 * @return {@literal null} when used in pipeline / transaction.
 	 * @since 2.1
+	 * @see <a href="https://redis.io/commands/hstrlen">Redis Documentation: HSTRLEN</a>
 	 */
 	@Nullable
 	Long hStrLen(byte[] key, byte[] field);

src/main/java/org/springframework/data/redis/connection/jedis/JedisClusterHashCommands.java

@@ -18,7 +18,6 @@
 import redis.clients.jedis.ScanParams;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -364,7 +363,11 @@ protected ScanIteration<Entry<byte[], byte[]>> doScan(long cursorId, ScanOptions
 	@Nullable
 	@Override
 	public Long hStrLen(byte[] key, byte[] field) {
-		return Long.class.cast(connection.execute("HSTRLEN", key, Collections.singleton(field)));
+
+		Assert.notNull(key, "Key must not be null");
+		Assert.notNull(field, "Field must not be null");
+
+		return connection.getCluster().hstrlen(key, field);
 	}
 
 	private DataAccessException convertJedisAccessException(Exception ex) {