grails - 从grails过滤器DSL内部访问常量

Question

在这里，我只是想对我需要的字符串键进行干燥处理，但这是唯一的
工作是将字符串直接放入分配中:request['RequestStopwatch.start'] = System.currentTimeMillis()。

有指针吗？

class RequestStopwatchFilters {

    def REQ_KEY = 'RequestStopwatch.start'

    def filters = {
        all(controller:'*', action:'*') {

            before = {

                log.debug(""+System.currentTimeMillis() + " " + request)
                // NULL pointer exception on REQ_KEY here:
                request[REQ_KEY] = System.currentTimeMillis()
            }
            after = { Map model ->
                if (log.isDebugEnabled()) {
                    // NULL pointer exception on REQ_KEY here:
                    log.debug("Stopped request before view at " + (System.currentTimeMillis() - request[REQ_KEY]) + "ms")
                }
            }
            afterView = { Exception e ->
                if (log.isDebugEnabled()) {
                    // NULL pointer exception on REQ_KEY here:
                    log.debug("Stopped request at " + (System.currentTimeMillis() - request[REQ_KEY]) + "ms")
                }
            }
        }
    }
}

Answer 1

将其设置为static或更好的public final static，例如:

class RequestStopwatchFilters {

    public final static String REQ_KEY = 'RequestStopwatch.start'
}

并将其用作:

RequestStopwatchFilters.REQ_KEY