获取spring web flow中之前执行的状态的ids

import org.springframework.webflow.execution.FlowExecution;
import org.springframework.webflow.execution.FlowSession;

public class FlowUtils {

    public static List<String> getPreviousStateIds(FlowExecution flowExecution) {
        List<String> previousStateIds = new ArrayList<>();

        FlowSession activeSession = flowExecution.getActiveSession();
        if (activeSession != null) {
            FlowSession previousSession = activeSession.getPreviousSession();
            if (previousSession != null) {
                previousStateIds = previousSession.getStateIds();
            }
        }

        return previousStateIds;
    }
}