在spring状态机中处理来自entry action类的代码/配置错误

Question

Builder<String, String> builder = StateMachineBuilder
                .<String, String> builder();
        builder.configureConfiguration()
        .withConfiguration()
        .autoStartup(false)
        .listener(listener())
                .beanFactory(
                this.applicationContext.getAutowireCapableBeanFactory());

private StateMachineListener<String, String> listener() {
        return new StateMachineListenerAdapter<String, String>() {
            @Override
            public void stateChanged(
                    org.springframework.statemachine.state.State<String, String> from,
                    org.springframework.statemachine.state.State<String, String> to) {
                LOGGER.debug("State change to " + to.getId());
            }

            @Override
            public void stateMachineError(
                    StateMachine<String, String> stateMachine, Exception e) {
                e.printStackTrace();
                LOGGER.debug("Ah... I am not getting executed when exception occurs from entry actions");
                LOGGER.debug("Error occured from  " + stateMachine.getState()
                        + "and the error is" + e.toString());
            }
        };
    }

Answer 1

您是正确的，StateMachineError或用@onstateMachineError注释的方法都不会在错误时执行。这在1.2版中得到了解决，它现在处于里程碑1。他们引入了erroraction，该操作在状态机上下文中执行：

用户总是可以手动捕获异常，但是对于为转换定义的操作，可以定义错误操作，如果引发异常，则调用错误操作。则从传递给该操作的StateContext中可以使用异常。

在状态机配置类中定义转换时，只需指定一个错误操作和所需的操作。来自文档中的示例：

public void configure(StateMachineTransitionConfigurer<States, Events> transitions)
        throws Exception {
    transitions
        .withExternal()
            .source(States.S1)
            .target(States.S2)
            .event(Events.E1)
            .action(action(), errorAction());
}