Use correct output for ZCARD command using LettuceConnection.execute(…).

We now provide a type hint for the ZCARD command.

Closes #2473

Original pull request: #2482

src/main/java/org/springframework/data/redis/connection/lettuce/LettuceConnection.java

@@ -58,7 +58,6 @@ import java.util.function.Supplier;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
 import org.springframework.beans.BeanUtils;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.dao.DataAccessException;
@@ -1212,6 +1211,7 @@ public class LettuceConnection extends AbstractRedisConnection {
 			COMMAND_OUTPUT_TYPE_MAPPING.put(STRLEN, IntegerOutput.class);
 			COMMAND_OUTPUT_TYPE_MAPPING.put(TTL, IntegerOutput.class);
 			COMMAND_OUTPUT_TYPE_MAPPING.put(ZADD, IntegerOutput.class);
+			COMMAND_OUTPUT_TYPE_MAPPING.put(ZCARD, IntegerOutput.class);
 			COMMAND_OUTPUT_TYPE_MAPPING.put(ZCOUNT, IntegerOutput.class);
 			COMMAND_OUTPUT_TYPE_MAPPING.put(ZINTERSTORE, IntegerOutput.class);
 			COMMAND_OUTPUT_TYPE_MAPPING.put(ZRANK, IntegerOutput.class);

src/test/java/org/springframework/data/redis/connection/lettuce/LettuceConnectionIntegrationTests.java

@@ -274,6 +274,16 @@ public class LettuceConnectionIntegrationTests extends AbstractConnectionIntegra
 						.contains("awesome".getBytes(), "cool".getBytes(), "supercalifragilisticexpialidocious".getBytes());
 	}
 
+	@Test // GH-2473
+	void testExecuteZcardShouldReturnNumericValue() {
+
+		connection.zAdd("spring", 1, "awesome");
+		connection.zAdd("spring", 1, "cool");
+		connection.zAdd("spring", 1, "supercalifragilisticexpialidocious");
+
+		assertThat(connection.execute("ZCARD", "spring")).isInstanceOf(Long.class).isEqualTo(3L);
+	}
+
 	@SuppressWarnings("unchecked")
 	@Test
 	public void testEvalShaArrayBytes() {