fix：

1、预测节点审批人查询，如果不存在，则直接返回空，避免类型转换异常
2、如果processVariables不为空，则使用前端传递的参数值

yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/candidate/strategy/dept/BpmTaskCandidateStartUserSelectStrategy.java

@@ -53,8 +53,11 @@ public class BpmTaskCandidateStartUserSelectStrategy extends AbstractBpmTaskCand
         Map<String, List<Long>> startUserSelectAssignees = FlowableUtils.getStartUserSelectAssignees(processInstance);
         Assert.notNull(startUserSelectAssignees, "流程实例({}) 的发起人自选审批人不能为空",
                 execution.getProcessInstanceId());
-        // 获得审批人
+        // 获得审批人，如果不存在，则直接返回空，避免类型转换异常
         List<Long> assignees = startUserSelectAssignees.get(execution.getCurrentActivityId());
+        if (CollUtil.isEmpty(assignees)){
+            return null;
+        }
         return new LinkedHashSet<>(assignees);
     }
 
@@ -68,8 +71,11 @@ public class BpmTaskCandidateStartUserSelectStrategy extends AbstractBpmTaskCand
         if (startUserSelectAssignees == null) {
             return Sets.newLinkedHashSet();
         }
-        // 获得审批人
+        // 获得审批人，如果不存在，则直接返回空，避免类型转换异常
         List<Long> assignees = startUserSelectAssignees.get(activityId);
+        if (CollUtil.isEmpty(assignees)){
+            return null;
+        }
         return new LinkedHashSet<>(assignees);
     }
 

yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/service/task/BpmProcessInstanceServiceImpl.java

@@ -173,10 +173,19 @@ public class BpmProcessInstanceServiceImpl implements BpmProcessInstanceService
             }
             startUserId = Long.valueOf(historicProcessInstance.getStartUserId());
             processInstanceStatus = FlowableUtils.getProcessInstanceStatus(historicProcessInstance);
-            // 如果流程变量为空，则使用历史流程变量
-            if (null == processVariables) {
-                processVariables = historicProcessInstance.getProcessVariables();
+            // 如果流程变量不为空，则用前端传递的新变量值覆盖历史的流程变量
+            Map<String, Object> historicVariables = historicProcessInstance.getProcessVariables();
+            if (null != processVariables) {
+                // 遍历新变量值，仅更新历史变量中存在的键
+                for (Map.Entry<String, Object> entry : processVariables.entrySet()) {
+                    String key = entry.getKey();
+                    if (historicVariables.containsKey(key)) {
+                        // 如果历史变量中存在该键，则用新值覆盖
+                        historicVariables.put(key, entry.getValue());
+                    }
+                }
             }
+            processVariables = historicVariables;
         }
         // 1.3 读取其它相关数据
         ProcessDefinition processDefinition = processDefinitionService.getProcessDefinition(