從零開始認識Dubbo

原創 Answer.AI.L 2019-08-28 18:35
原文鏈接：https://juejin.im/post/5d312adb5188253d9b127352

Dubbo是什麼

dubbo.apache.org/zh-cn/index…

Apache Dubbo™ 是一款高性能Java RPC框架。

Dubbo是一個分佈式服務框架，致力於提供高性能和透明化的RPC遠程服務調用方案，以及SOA服務治理方案。簡單的說，dubbo就是個服務框架，如果沒有分佈式的需求，其實是不需要用的，只有在分佈式的時候，纔有dubbo這樣的分佈式服務框架的需求，並且本質上是個服務調用的東東，說白了就是個遠程服務調用的分佈式框架(告別Web Service模式中的WSDL(網絡服務描述語言,Web Services Description Language)，以服務者與消費者的方式在dubbo上註冊) 其核心部分包含:

  1. 遠程通訊: 提供對多種基於長連接的NIO框架抽象封裝，包括多種線程模型，序列化，以及“請求-響應”模式的信息交換方式。
  2. 集羣容錯: 提供基於接口方法的透明遠程過程調用，包括多協議支持，以及軟負載均衡，失敗容錯，地址路由，動態配置等集羣支持。
  3. 自動發現: 基於註冊中心目錄服務，使服務消費方能動態的查找服務提供方，使地址透明，使服務提供方可以平滑增加或減少機器。

 

Dubbo能做什麼

  • 透明化的遠程方法調用，就像調用本地方法一樣調用遠程方法，只需簡單配置，沒有任何API侵入。
  • 軟負載均衡及容錯機制，可在內網替代F5等硬件負載均衡器，降低成本，減少單點。
  • 服務自動註冊與發現，不再需要寫死服務提供方地址，註冊中心基於接口名查詢服務提供者的IP地址，並且能夠平滑添加或刪除服務提供者。

Dubbo採用全spring配置方式，透明化接入應用，對應用沒有任何API侵入，只需用Spring加載Dubbo的配置即可，Dubbo基於Spring的Schema擴展進行加載。

 

Dubbo架構

在這裏插入圖片描述

節點角色說明：

  • Provider: 暴露服務的服務提供方。
  • Consumer: 調用遠程服務的服務消費方。
  • Registry: 服務註冊與發現的註冊中心。
  • Monitor: 統計服務的調用次調和調用時間的監控中心。
  • Container: 服務運行容器。

調用關係說明：

  1. 服務容器負責啓動，加載，運行服務提供者。
  2. 服務提供者在啓動時，向註冊中心註冊自己提供的服務。
  3. 服務消費者在啓動時，向註冊中心訂閱自己所需的服務。
  4. 註冊中心返回服務提供者地址列表給消費者，如果有變更，註冊中心將基於長連接推送變更數據給消費者。
  5. 服務消費者，從提供者地址列表中，基於軟負載均衡算法，選一臺提供者進行調用，如果調用失敗，再選另一臺調用。
  6. 服務消費者和提供者，在內存中累計調用次數和調用時間，定時每分鐘發送一次統計數據到監控中心。

 

Dubbo的使用方法

Dubbo採用全Spring配置方式，透明化接入應用，對應用沒有任何API侵入，只需用Spring加載Dubbo的配置即可，Dubbo基於Spring的Schema擴展進行加載。如果不想使用Spring配置，可以通過API的方式進行調用（註解式，不推薦使用）

下載安裝zookeeper註冊中心（不建議使用multicast）

Windows

下載地址： www.apache.org/dyn/closer.… -> zookeeper

MacOS

下載地址： www.apache.org/dyn/closer.…

使用方法：下載解壓即可，進入解壓目錄運行zkServer.sh start啓動註冊服務中心

Linux

下載地址： www.apache.org/dyn/closer.…

使用方法：下載解壓即可，進入解壓目錄運行zkServer.sh start啓動註冊服務中心

服務提供者

1.定義服務接口(該接口需單獨打包，在服務提供方和消費方共享)

DemoService.java

package org.apache.dubbo.demo;

public interface DemoService {
    String sayHello(String name);
}

2.服務提供方實現接口：(對服務消費方隱藏實現)
DemoServiceImpl.java

package org.apache.dubbo.demo.provider;
 
import org.apache.dubbo.demo.DemoService;
 
public class DemoServiceImpl implements DemoService {
    public String sayHello(String name) {
        return "Hello " + name;
    }
}

3.用Spring配置聲明暴露服務：

?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"
    xsi:schemaLocation="http://www.springframework.org/schema/beans        http://www.springframework.org/schema/beans/spring-beans-4.3.xsd        http://dubbo.apache.org/schema/dubbo        http://dubbo.apache.org/schema/dubbo/dubbo.xsd">
 
    <!-- 提供方應用信息，用於計算依賴關係 -->
    <dubbo:application name="hello-world-app"  />
 
    <!-- 使用multicast廣播註冊中心暴露服務地址 -->
    <dubbo:registry address="multicast://224.5.6.7:1234" />
 
    <!-- 用dubbo協議在20880端口暴露服務 -->
    <dubbo:protocol name="dubbo" port="20880" />
 
    <!-- 聲明需要暴露的服務接口 -->
    <dubbo:service interface="org.apache.dubbo.demo.DemoService" ref="demoService" />
 
    <!-- 和本地bean一樣實現服務 -->
    <bean id="demoService" class="org.apache.dubbo.demo.provider.DemoServiceImpl" />
</beans>

4.加載Spring配置，啓動服務：

import org.springframework.context.support.ClassPathXmlApplicationContext;
 
public class Provider {
    public static void main(String[] args) throws Exception {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"spring/dubbo-provider.xml"});
        context.start();
        System.in.read(); // 按任意鍵退出
    }
}

或者使用springBoot啓動

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ImportResource;

@SpringBootApplication
@ImportResource("spring/dubbo-provider.xml")
public class DubboProviderApplication {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(DubboProviderApplication.class, args);

    }
}

服務消費者：

applicationContext-dubbo.xml 中註冊自己需要調用的接口。

1.通過Spring配置引用遠程服務

dubbo-consumer.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"
    xsi:schemaLocation="http://www.springframework.org/schema/beans        http://www.springframework.org/schema/beans/spring-beans-4.3.xsd        http://dubbo.apache.org/schema/dubbo        http://dubbo.apache.org/schema/dubbo/dubbo.xsd">
 
    <!-- 消費方應用名，用於計算依賴關係，不是匹配條件，不要與提供方一樣 -->
    <dubbo:application name="consumer-of-helloworld-app"  />
 
    <!-- 使用multicast廣播註冊中心暴露發現服務地址 -->
    <dubbo:registry address="multicast://224.5.6.7:1234" />
 
    <!-- 生成遠程服務代理，可以和本地bean一樣使用demoService -->
    <dubbo:reference id="demoService" interface="org.apache.dubbo.demo.DemoService" />
</beans>

2.加載Spring配置，並調用遠程服務：
Consumer.java

import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.apache.dubbo.demo.DemoService;
 
public class Consumer {
    public static void main(String[] args) throws Exception {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"spring/dubbo-consumer.xml"});
        context.start();
        DemoService demoService = (DemoService)context.getBean("demoService"); // 獲取遠程服務代理
        String hello = demoService.sayHello("world"); // 執行遠程方法
        System.out.println( hello ); // 顯示調用結果
    }
}

或者使用springBoot啓動

import org.apache.dubbo.common.logger.Logger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ImportResource;

@SpringBootApplication
@ImportResource("spring/dubbo-consumer.xml")
public class DubboConsumerApplicaiton {

    public static final Logger logger = LoggerFactory.getLogger(DubboConsumerApplicaiton.class);

    public static void main(String[] args) {
        SpringApplication.run(DubboConsumerApplicaiton.class, args);

    }
}

並添加對應的restful接口提供接口訪問

@RequestMapping("/demo")
public ModelAndView testDemo() {
    ModelAndView modelAndView = new ModelAndView("index");
    org.apache.dubbo.rpc.RpcContext.getContext().setAttachment(Constants.TAG_KEY, "gray");
    modelAndView.addObject("result", demoService.sayHello("Dubbo Meetup"));
    return modelAndView;
}

修改對應index頁面

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>Vertical centering in valid CSS</title>
    <style type="text/css">
        .text{text-align:center;  }
    </style>

</head>
<body>
<div class="text" style="margin-top:300px;font-size: 50px;">${result.msg}</div>
<div class="text" style="margin-top:30px;font-size: 35px;color:#5079bb;">From : ${result.userName}</div>
</body>
</html>

3.dubbo管理頁面：

github.com/apache/dubb…

啓動後訪問 http://localhost:8080/dubbo-admin/

輸入賬號密碼： root/root

 

使用Dubbo可能遇到的問題

1、org.springframework.beans.factory.BeanCreationException

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mgmtFactoryInoutDetailsController': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'goodsInoutServiceImpl' available
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues(CommonAnnotationBeanPostProcessor.java:321) ~[spring-context-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1268) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:312) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:308) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.web.method.HandlerMethod.createWithResolvedBean(HandlerMethod.java:299) ~[spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.getHandlerInternal(AbstractHandlerMethodMapping.java:323) ~[spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.getHandlerInternal(AbstractHandlerMethodMapping.java:61) ~[spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.handler.AbstractHandlerMapping.getHandler(AbstractHandlerMapping.java:352) ~[spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.getHandler(DispatcherServlet.java:1160) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:940) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) [servlet-api.jar:na]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) [servlet-api.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-websocket.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90) [shiro-core-1.2.4.jar:1.2.4]
	at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83) [shiro-core-1.2.4.jar:1.2.4]
	at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383) [shiro-core-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) [shiro-web-1.2.4.jar:1.2.4]
	at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:347) [spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:263) [spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) [spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at ue.common.filter.MultiPrefixHideUrlFilter.doFilter(MultiPrefixHideUrlFilter.java:76) [YKXCommon-3.3.01.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at ue.common.filter.PageableFilter.doFilterInternal(PageableFilter.java:48) [YKXCommon-3.3.01.jar:na]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) [catalina.jar:8.0.36]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) [catalina.jar:8.0.36]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) [catalina.jar:8.0.36]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) [catalina.jar:8.0.36]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [catalina.jar:8.0.36]
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616) [catalina.jar:8.0.36]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) [catalina.jar:8.0.36]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528) [catalina.jar:8.0.36]
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099) [tomcat-coyote.jar:8.0.36]
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:670) [tomcat-coyote.jar:8.0.36]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520) [tomcat-coyote.jar:8.0.36]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476) [tomcat-coyote.jar:8.0.36]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_131]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_131]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-util.jar:8.0.36]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_131]
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'goodsInoutServiceImpl' available
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:687) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1213) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:284) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:275) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.autowireResource(CommonAnnotationBeanPostProcessor.java:522) ~[spring-context-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.getResource(CommonAnnotationBeanPostProcessor.java:496) ~[spring-context-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor$ResourceElement.getResourceToInject(CommonAnnotationBeanPostProcessor.java:627) ~[spring-context-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement.inject(InjectionMetadata.java:169) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues(CommonAnnotationBeanPostProcessor.java:318) ~[spring-context-4.3.16.RELEASE.jar:4.3.16.RELEASE]
	... 67 common frames omitted

原因分析：

Error creating bean with name 'mgmtFactoryInoutDetailsController': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'goodsInoutServiceImpl' available
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues(CommonAnnotationBeanPostProcessor.java:321)

解決方案
在dubbo-provider.xml添加對應的聲明暴露服務

<dubbo:service interface="ue.biz.service.biz.GoodsInoutService" ref="goodsInoutServiceImpl"/>

在dubbo-consumer.xml添加對應的服務訂閱

<dubbo:reference id="goodsInoutServiceImpl" interface="ue.biz.service.biz.GoodsInoutService"/>

2、org.apache.dubbo.rpc.RpcException

org.apache.dubbo.rpc.RpcException: No provider available from registry 120.79.246.86:2181 for service ue.biz.service.bas.EnterpriseUserService on consumer 192.168.0.63 use dubbo version 2.7.0, please check status of providers(disabled, not registered or in blacklist).
	at org.apache.dubbo.registry.integration.RegistryDirectory.doList(RegistryDirectory.java:522) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.cluster.directory.AbstractDirectory.list(AbstractDirectory.java:82) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.cluster.support.AbstractClusterInvoker.list(AbstractClusterInvoker.java:274) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.cluster.support.AbstractClusterInvoker.invoke(AbstractClusterInvoker.java:238) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.cluster.support.wrapper.MockClusterInvoker.invoke(MockClusterInvoker.java:75) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.proxy.InvokerInvocationHandler.invoke(InvokerInvocationHandler.java:57) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.common.bytecode.proxy7.getCurrent(proxy7.java) ~[dubbo-2.7.0.jar:2.7.0]
	at ue.mgmt.controller.CommonController.main(CommonController.java:787) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_131]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_131]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_131]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_131]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:849) ~[spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:760) ~[spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) [servlet-api.jar:na]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) [spring-webmvc-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) [servlet-api.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-websocket.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90) [shiro-core-1.2.4.jar:1.2.4]
	at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83) [shiro-core-1.2.4.jar:1.2.4]
	at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383) [shiro-core-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362) [shiro-web-1.2.4.jar:1.2.4]
	at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) [shiro-web-1.2.4.jar:1.2.4]
	at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:347) [spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:263) [spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) [spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at ue.common.filter.MultiPrefixHideUrlFilter.doFilter(MultiPrefixHideUrlFilter.java:76) [YKXCommon-3.3.01.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at ue.common.filter.PageableFilter.doFilterInternal(PageableFilter.java:48) [YKXCommon-3.3.01.jar:na]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.20.RELEASE.jar:4.3.20.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.36]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.36]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) [catalina.jar:8.0.36]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) [catalina.jar:8.0.36]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) [catalina.jar:8.0.36]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) [catalina.jar:8.0.36]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [catalina.jar:8.0.36]
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616) [catalina.jar:8.0.36]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) [catalina.jar:8.0.36]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528) [catalina.jar:8.0.36]
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099) [tomcat-coyote.jar:8.0.36]
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:670) [tomcat-coyote.jar:8.0.36]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520) [tomcat-coyote.jar:8.0.36]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476) [tomcat-coyote.jar:8.0.36]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_131]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_131]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-util.jar:8.0.36]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_131]

原因分析

No provider available from registry 120.79.246.86:2181 for service ue.biz.service.bas.EnterpriseUserService on consumer 192.168.0.63 use dubbo version 2.7.0, please check status of providers

解決方案
可能是因爲providers沒有啓動，或者是provider對應暴露的服務被禁用，啓動providers或者解除禁用即可

3、java.lang.IllegalStateException

java.lang.IllegalStateException: Illegal access: this web application instance has been stopped already. Could not load [io.netty.channel.nio.NioEventLoop]. The following stack trace is thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access.
	at org.apache.catalina.loader.WebappClassLoaderBase.checkStateForResourceLoading(WebappClassLoaderBase.java:1352)
	at org.apache.catalina.loader.WebappClassLoaderBase.checkStateForClassLoading(WebappClassLoaderBase.java:1340)
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1205)
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1166)
	at ch.qos.logback.classic.spi.PackagingDataCalculator.loadClass(PackagingDataCalculator.java:207)
	at ch.qos.logback.classic.spi.PackagingDataCalculator.bestEffortLoadClass(PackagingDataCalculator.java:226)
	at ch.qos.logback.classic.spi.PackagingDataCalculator.computeBySTEP(PackagingDataCalculator.java:138)
	at ch.qos.logback.classic.spi.PackagingDataCalculator.populateUncommonFrames(PackagingDataCalculator.java:113)
	at ch.qos.logback.classic.spi.PackagingDataCalculator.populateFrames(PackagingDataCalculator.java:105)
	at ch.qos.logback.classic.spi.PackagingDataCalculator.calculate(PackagingDataCalculator.java:57)
	at ch.qos.logback.classic.spi.ThrowableProxy.calculatePackagingData(ThrowableProxy.java:147)
	at ch.qos.logback.classic.spi.LoggingEvent.<init>(LoggingEvent.java:124)
	at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:440)
	at ch.qos.logback.classic.Logger.filterAndLog_0_Or3Plus(Logger.java:396)
	at ch.qos.logback.classic.Logger.warn(Logger.java:713)
	at io.netty.util.internal.logging.Slf4JLogger.warn(Slf4JLogger.java:151)
	at io.netty.channel.nio.NioEventLoop.handleLoopException(NioEventLoop.java:486)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:469)
	at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.lang.Thread.run(Thread.java:748)

原因分析

this web application instance has been stopped already.
所以，需要重啓Tomcat的情況下才有可能發上，這是第一個出錯條件。
Could not load [io.netty.channel.nio.NioEventLoop].
看這個不能直接推出問題產生條件，但是很明顯是關於加載的。

解決方案

總結以上兩點，通俗點講，就是重啓了工程（可能是因爲直接修改代碼，工程reload了）， 並且，連過了數據庫（登錄等），纔出現了上述報錯信息。原因是因爲在tomcat重啓的時候，之前的tomcat的線程還沒有完全關閉，最新啓動tomcat就會報這個異常。

4、org.apache.dubbo.remoting.TimeoutException

Caused by: org.apache.dubbo.remoting.TimeoutException: Waiting server-side response timeout by scan timer. start time: 2019-07-04 15:05:41.363, end time: 2019-07-04 15:05:51.388, client elapsed: 94 ms, server elapsed: 9931 ms, timeout: 10000 ms, request: Request [id=0, version=2.0.2, twoway=true, event=false, broken=false, data=RpcInvocation [methodName=find, parameterTypes=[class ue.biz.entity.sys.Permission$Type], arguments=[url], attachments={path=ue.biz.service.sys.PermissionService, interface=ue.biz.service.sys.PermissionService, version=0.0.0, timeout=10000}]], channel: /192.168.0.46:54424 -> /192.168.0.46:20880
	at org.apache.dubbo.remoting.exchange.support.DefaultFuture.returnFromResponse(DefaultFuture.java:296) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.remoting.exchange.support.DefaultFuture.get(DefaultFuture.java:191) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.remoting.exchange.support.DefaultFuture.get(DefaultFuture.java:164) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.protocol.dubbo.DubboInvoker.doInvoke(DubboInvoker.java:108) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.protocol.AbstractInvoker.invoke(AbstractInvoker.java:156) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.monitor.support.MonitorFilter.invoke(MonitorFilter.java:88) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:73) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.protocol.dubbo.filter.FutureFilter.invoke(FutureFilter.java:49) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:73) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.filter.ConsumerContextFilter.invoke(ConsumerContextFilter.java:54) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:73) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.listener.ListenerInvokerWrapper.invoke(ListenerInvokerWrapper.java:77) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.protocol.InvokerWrapper.invoke(InvokerWrapper.java:56) ~[dubbo-2.7.0.jar:2.7.0]
	at org.apache.dubbo.rpc.cluster.support.FailoverClusterInvoker.doInvoke(FailoverClusterInvoker.java:80) ~[dubbo-2.7.0.jar:2.7.0]
	... 65 common frames omitted

原因分析

org.apache.dubbo.remoting.TimeoutException: Waiting server-side response timeout by scan timer. start time: 2019-07-04 15:05:41.363, end time: 2019-07-04 15:05:51.388, client elapsed: 94 ms, server elapsed: 9931 ms, timeout: 10000 ms, request: Request [id=0, version=2.0.2, twoway=true, event=false, broken=false, data=RpcInvocation [methodName=find, parameterTypes=[class ue.biz.entity.sys.Permission$Type], arguments=[url], attachments={path=ue.biz.service.sys.PermissionService

解決方案
在dubbo-provider.xml增加超時時間

<dubbo:provider delay="-1" timeout="10000" retries="0"/>

 

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