grails - Grails 中的 Web 流 - 困惑

Question

每次接触 web 流时我都感到痛苦，我认为与 Spring MVC 相对的 grails 世界中的事情可能更简单易懂，但似乎并非如此。
我有一个简单的情况，我想在显示 Web 流的第一页时使用已经在流范围内的预填充命令对象启动 Web 流。命令对象基本上是从域对象中保存值的副本
这是我的命令对象:

@grails.validation.Validateable(nullable=false)
class PatientEditFlowCommand implements Serializable{

StepOneCommand stepOneCommand

PatientEditFlowCommand(Patient patient){

    stepOneCommand = new StepOneCommand(
            patientName : "${patient.appUser?.firstName} ${patient.appUser?.lastName}",
            patientDoctorId : patient.doctor?.id,
            patientNurseId : patient.nurse?.id,
            patientStartDate : patient.startDate,
            patientEndDate : patient.endDate,
            patientDrugRegimeId: patient.regime?.id
    )

}

static constraints = {


}
}


@grails.validation.Validateable(nullable=false)
class StepOneCommand implements Serializable{

String patientName //wont be editable

Long patientDoctorId  //user id of assigned doctor
Long patientNurseId   //user id of assigned doctor

Date patientStartDate
Date patientEndDate

Long patientDrugRegimeId

static constraints = {
    patientDoctorId(nullable: false)
    patientNurseId(nullable: false)
    patientStartDate(nullable: false)
    patientEndDate(nullable: false)
    patientDrugRegimeId(nullable: false)
}
}


@grails.validation.Validateable(nullable=false)
class StepTwoCommand implements Serializable{

static constraints = {

}
}

这是我在 Controller 中的流程:

    def newEditFlow = {

    init {
        //start the flow by transferring domain obj into a command object
        action {
            Patient patient = Patient.get(params.id)
            [patientEditFlowCommand:new PatientEditFlowCommand(patient)]
            success()
        }
        on ("success"){

        }.to "stepOne"

    }

    stepOne{

        on("next") {

        }.to("stepTwo")

        on("cancel").to("finish")

    }

    stepTwo{

        on("next") {

        }.to("stepThree")

        on("previous").to("stepOne")
    }

    stepThree{

        on("next") {

        }.to("stepFour")

        on("previous").to("stepTwo")
    }

    stepFour{

        on("next") {

        }.to("finish")

        on("previous").to("stepThree")
    }

    finish{
        redirect(controller:'patient',action: "list")
    }
}

但是当我导航到第一个转换时，我得到了这个

Error 500: Internal Server Error

URI
/ivfportal/patient/newEdit/3
Class
java.lang.NullPointerException
Message
null
Around line 74 of GrailsFlowExecutorImpl.java

71:        }72:73:        try {74:            return super.resumeExecution(flowExecutionKey, context);75:        }76:        catch (FlowExecutionRestorationFailureException e) {77:            if (e.getCause() instanceof SnapshotUnmarshalException) {
Around line 53 of GrailsFlowHandlerAdapter.java

50:            request.setAttribute(GrailsApplicationAttributes.CONTROLLER, controllerInstance);51:        }52:53:        return super.handle(request, response, handler);54:    }55:56:    public void setGrailsApplication(GrailsApplication grailsApplication) {
Around line 189 of PageFragmentCachingFilter.java

186:            if (method == null) {187:               log.debug("No cacheable method found for {}:{} {}",188:                     new Object[] { request.getMethod(), request.getRequestURI(), getContext() });189:               chain.doFilter(request, response);190:              return;191:         }192:           Collection<CacheOperation> cacheOperations = cacheOperationSource.getCacheOperations(
Around line 63 of AbstractFilter.java

60:     try {61:            // NO_FILTER set for RequestDispatcher forwards to avoid double gzipping62:         if (filterNotDisabled(request)) {63:                doFilter(request, response, chain);64:          }65:            else {66:               chain.doFilter(req, res);
Around line 45 of DevModeSanityFilter.groovy

42:            response.contentType = "text/html"43:            response.writer << RELOADING_DOC44:        } else {45:            chain.doFilter(request, response)46:47:            if (request.getAttribute('resources.need.layout')) {48:                def dispositionsLeftOver = DispositionsUtils.getRequestDispositionsRemaining(request)
Around line 53 of GrailsAnonymousAuthenticationFilter.java

50:51:      applyAnonymousForThisRequest((HttpServletRequest)req);52:53:        chain.doFilter(req, res);54:    }55:56: protected void applyAnonymousForThisRequest(HttpServletRequest request) {
Around line 139 of RestAuthenticationFilter.groovy

有人看到我哪里出错了吗？在 Grails 中是否有一种更简单但仍然整洁的方法来通过多页面流收集数据？

Answer 1

您可以通过对话将参数传递给流程。
对话.患者 = Patient.get(params.id)
您在 Web 流中使用的每个类也必须是可序列化的