Support scan in RedisTemplate.

Closes #2260
Original pull request: #2263.

src/main/java/org/springframework/data/redis/core/RedisOperations.java

@@ -45,6 +45,7 @@ import org.springframework.util.Assert;
  * @author Mark Paluch
  * @author ihaohong
  * @author Todd Merrill
+ * @author Chen Li
  */
 public interface RedisOperations<K, V> {
 
@@ -259,6 +260,16 @@ public interface RedisOperations<K, V> {
 	@Nullable
 	Set<K> keys(K pattern);
 
+	/**
+	 * Use a {@link Cursor} to iterate over keys. <br />
+	 * <strong>Important:</strong> Call {@link Cursor#close()} when done to avoid resource leak.
+	 *
+	 * @param options must not be {@literal null}.
+	 * @return never {@literal null}.
+	 * @see <a href="https://redis.io/commands/scan">Redis Documentation: SCAN</a>
+	 */
+	Cursor<K> scan(ScanOptions options);
+
 	/**
 	 * Return a random key from the keyspace.
 	 *

src/main/java/org/springframework/data/redis/core/RedisTemplate.java

@@ -83,6 +83,7 @@ import org.springframework.util.CollectionUtils;
  * @author Mark Paluch
  * @author Denis Zavedeev
  * @author ihaohong
+ * @author Chen Li
  * @param <K> the Redis key type against which the template works (usually a String)
  * @param <V> the Redis value type against which the template works
  * @see StringRedisTemplate
@@ -801,6 +802,15 @@ public class RedisTemplate<K, V> extends RedisAccessor implements RedisOperation
 		return keySerializer != null ? SerializationUtils.deserialize(rawKeys, keySerializer) : (Set<K>) rawKeys;
 	}
 
+	@Override
+	public Cursor<K> scan(ScanOptions options) {
+		Assert.notNull(options, "ScanOptions must not be null!");
+
+		return executeWithStickyConnection(
+				(RedisCallback<Cursor<K>>) connection -> new ConvertingCursor<>(connection.scan(options),
+						this::deserializeKey));
+	}
+
 	@Override
 	public Boolean persist(K key) {