Activity工作流流转条件报错Transaction rolled back because it has been marked as rollback-only

给工作流设置流转条件后，发现工作流无法进行下去，报如下错

Transaction rolled back because it has been marked as rollback-only

Unknown property used in expression: ${state==A}

org.activiti.engine.impl.javax.el.PropertyNotFoundException: Cannot resolve identifier 'A'

因为计划是根据A，B，C走三个分支，所以索性流转条件也这样设置，结果报如上错误

解决：将A,B,C改为1,2,3就好了....state==1,state==2,state==3