[FIX-#5233][API] Fix bug ofREPEAT RUNNING processInstance throw exceprion (#5234)

* fix bug of REPEAT RUNNING throw exception

Co-authored-by: wangxj <wangxj31>

dolphinscheduler-api/src/main/java/org/apache/dolphinscheduler/api/service/impl/ExecutorServiceImpl.java

@@ -24,7 +24,6 @@ import static org.apache.dolphinscheduler.common.Constants.CMD_PARAM_START_NODE_
 import static org.apache.dolphinscheduler.common.Constants.CMD_PARAM_START_PARAMS;
 import static org.apache.dolphinscheduler.common.Constants.MAX_TASK_TIMEOUT;
 
-import org.apache.commons.collections.MapUtils;
 import org.apache.dolphinscheduler.api.enums.ExecuteType;
 import org.apache.dolphinscheduler.api.enums.Status;
 import org.apache.dolphinscheduler.api.service.ExecutorService;
@@ -57,6 +56,8 @@ import org.apache.dolphinscheduler.dao.mapper.ProjectMapper;
 import org.apache.dolphinscheduler.service.process.ProcessService;
 import org.apache.dolphinscheduler.service.quartz.cron.CronUtils;
 
+import org.apache.commons.collections.MapUtils;
+
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.HashMap;
@@ -266,7 +267,10 @@ public class ExecutorServiceImpl extends BaseServiceImpl implements ExecutorServ
         Map<String, Object> commandMap = JSONUtils.toMap(processInstance.getCommandParam(), String.class, Object.class);
         String startParams = null;
         if (MapUtils.isNotEmpty(commandMap) && executeType == ExecuteType.REPEAT_RUNNING) {
-            startParams = (commandMap.get(Constants.CMD_PARAM_START_PARAMS)).toString();
+            Object startParamsJson = commandMap.get(Constants.CMD_PARAM_START_PARAMS);
+            if (startParamsJson != null) {
+                startParams = startParamsJson.toString();
+            }
         }
 
         switch (executeType) {