【功能新增】 增加审批人分配策略：选择表单内成员

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

@@ -0,0 +1,50 @@
+package cn.iocoder.yudao.module.bpm.framework.flowable.core.candidate.strategy.user;
+
+import cn.hutool.core.convert.Convert;
+import cn.hutool.core.lang.Assert;
+import cn.hutool.core.map.MapUtil;
+import cn.iocoder.yudao.module.bpm.framework.flowable.core.candidate.BpmTaskCandidateStrategy;
+import cn.iocoder.yudao.module.bpm.framework.flowable.core.enums.BpmTaskCandidateStrategyEnum;
+import org.flowable.bpmn.model.BpmnModel;
+import org.flowable.engine.delegate.DelegateExecution;
+import org.springframework.stereotype.Component;
+
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import static cn.iocoder.yudao.framework.common.util.collection.SetUtils.asSet;
+
+/**
+ * 表单内用户字段 {@link BpmTaskCandidateUserStrategy} 实现类
+ *
+ * @author jason
+ */
+@Component
+public class BpmTaskCandidateUserFieldOnFormStrategy implements BpmTaskCandidateStrategy  {
+
+    @Override
+    public BpmTaskCandidateStrategyEnum getStrategy() {
+        return BpmTaskCandidateStrategyEnum.USER_FIELD_ON_FORM;
+    }
+
+    @Override
+    public void validateParam(String param) {
+        Assert.notEmpty(param, "表单内用户字段不能为空");
+    }
+
+    @Override
+    public Set<Long> calculateUsersByTask(DelegateExecution execution, String param) {
+        Object result =  execution.getVariable(param);
+        return Convert.toSet(Long.class, result);
+    }
+
+    @Override
+    public Set<Long> calculateUsersByActivity(BpmnModel bpmnModel, String activityId,
+                                              String param, Long startUserId, String processDefinitionId,
+                                              Map<String, Object> processVariables) {
+        Long result = MapUtil.getLong(processVariables, param);
+        return result != null ? asSet(result) : new HashSet<>();
+    }
+
+}

yudao-module-bpm/yudao-module-bpm-biz/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/enums/BpmTaskCandidateStrategyEnum.java

@@ -29,6 +29,7 @@ public enum BpmTaskCandidateStrategyEnum implements IntArrayValuable {
     START_USER_DEPT_LEADER(37, "发起人部门负责人"),
     START_USER_DEPT_LEADER_MULTI(38, "发起人连续多级部门的负责人"),
     USER_GROUP(40, "用户组"),
+    USER_FIELD_ON_FORM(50, "表单内用户字段"),
     EXPRESSION(60, "流程表达式"), // 表达式 ExpressionManager
     ASSIGN_EMPTY(1, "审批人为空"),
     ;