dubbo启动出现java.lang.IllegalStateException: ref not allow null!

dubbo（消费方）启动时报如下错误：

18/02/11 14:50:01 ERROR org.springframework.web.servlet.DispatcherServlet:502: Context initialization failed
java.lang.IllegalStateException: ref not allow null!

    at com.alibaba.dubbo.config.ServiceConfig.checkRef(ServiceConfig.java:248)
    at com.alibaba.dubbo.config.ServiceConfig.doExport(ServiceConfig.java:203)
    at com.alibaba.dubbo.config.ServiceConfig.export(ServiceConfig.java:143)
    at com.alibaba.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:109)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:167)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:383)
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:337)
    at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:882)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:545)
    at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:668)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:634)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:682)
    at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:553)
    at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:494)
    at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
    at javax.servlet.GenericServlet.init(GenericServlet.java:158)
    at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1183)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1099)
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:779)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:133)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

最终确定修改错误后，才明白，它报的错的意思是我的dubbo的consumer.xml配置没有ref引用，我的消费方配置为

完全的把消费方的配置写错了，怪不得提示ref not allow null!，我的配置完全没有ref嘛，最后修改为

然后，可以正常的运行了！

总结：这次错误主要是我把提供方provider.xml的配置直接copy过来造成的错误。