Java：Dubbo的使用方式介绍

谁践踏了优雅 2022-02-17 05:19 252阅读 0赞

通过一个简单的例子，介绍Dubbo环境的搭建。

使用到的组件：

> zookeeper    3.5.4-beta  
> dubbo           2.7.1  
> org.slf4j        1.7.26  
> log4j             2.11.2  
> curator          4.2.0

准备4个工程以及包含的类和配置文件：

> **SSO-API**  
>   com.test.sso.intf.SSODataStore  
>   com.test.sso.intf.SSOServiceProvider  
> **SSO-DataStore**  
>   com.test.sso.App  
>   com.test.sso.SSODataStoreImpl  
>   sso-service-dataStore.xml  
>   log4j2.xml  
> **SSO-ServiceProvider**  
>   com.test.sso.App  
>   com.test.sso.SSOServiceProviderImpl  
>   sso-service-provider.xml  
>   log4j2.xml  
> **SSO-Consumer**  
>   com.test.sso.App  
>   sso-service-consumer.xml  
>   log4j2.xml

其中，SSO-API只存放接口，SSO-ServiceProvider即是Provider又是Consumer，SSO-DataStore只是Provider，SSO-Consumer只是Consumer，调用关系为SSO-Consumer -> SSO-ServiceProvider -> SSO-DataStore。

Maven的pom.xml文件中统一使用如下配置：

<properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      <dubbo.version>2.7.1</dubbo.version>
      <log4j2.version>2.11.2</log4j2.version>
      <curator.version>4.2.0</curator.version>
      <disruptor.version>3.4.2</disruptor.version>
      <slf4j.version>1.7.26</slf4j.version>
    </properties>
    
    <dependencies>
      <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-core</artifactId>
        <version>${log4j2.version}</version>
      </dependency>
      <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-api</artifactId>
        <version>${log4j2.version}</version>
      </dependency>
      <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-slf4j-impl</artifactId>
        <version>${log4j2.version}</version>
      </dependency>
      <dependency>
        <groupId>com.lmax</groupId>
        <artifactId>disruptor</artifactId>
        <version>${disruptor.version}</version>
      </dependency>
      <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>${slf4j.version}</version>
      </dependency>
      <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>jcl-over-slf4j</artifactId>
        <version>${slf4j.version}</version>
      </dependency>
    
      <dependency>
        <groupId>org.apache.dubbo</groupId>
        <artifactId>dubbo</artifactId>
        <version>${dubbo.version}</version>
      </dependency>
      <dependency>
        <groupId>org.apache.curator</groupId>
        <artifactId>curator-framework</artifactId>
        <version>${curator.version}</version>
      </dependency>
      <dependency>
        <groupId>org.apache.curator</groupId>
        <artifactId>curator-client</artifactId>
        <version>${curator.version}</version>
      </dependency>
      <dependency>
        <groupId>org.apache.curator</groupId>
        <artifactId>curator-recipes</artifactId>
        <version>${curator.version}</version>
      </dependency>
    
      <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>3.8.1</version>
        <scope>test</scope>
      </dependency>
    </dependencies>

如果zookeeper使用的版本为3.5.4-beta，则curator要用4.2.0的版本。如果zookeeper使用的版本为3.4.14，则curator要在依赖中将zookeeper排除，同时要单独添加对zookeeper版本3.4.X的依赖。由于spring中还用到了common-logging，所以需要使用jcl-over-slf4j将对common-logging API的调用转到slf4j上。另外，由于要用到异步logger，所以添加disruptor。

log4j2.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
    <configuration status="error">
      <Properties>
        <Property name="baseDir">D:/Temp/eclipse/logs</Property>
        <Property name="patternFormat">%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level[%3T]%c.%M:%L - %m%xEx%n</Property>
      </Properties>
    
      <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
          <PatternLayout pattern="${patternFormat}" />
        </Console>
    
        <RollingFile name="data_log" fileName="${baseDir}/data.log" filePattern="${baseDir}/data-%d{yyyyMMddHHmm}.log">
          <PatternLayout pattern="${patternFormat}" />
          <Policies>
            <TimeBasedTriggeringPolicy interval="1" modulate="true" />
            <SizeBasedTriggeringPolicy size="250MB" />
          </Policies>
          <DefaultRolloverStrategy>
            <Delete basePath="${baseDir}" maxDepth="2">
              <IfFileName glob="data-*.log" />
              <IfLastModified age="10m" />
            </Delete>
          </DefaultRolloverStrategy>
        </RollingFile>
      </Appenders>
    
      <Loggers>
        <asyncLogger name="com.test.sso" level="info" additivity="false" includeLocation="true">
          <AppenderRef ref="data_log" />
        </asyncLogger>
    
        <Root level="info" includeLocation="true">
          <AppenderRef ref="Console" />
        </Root>
      </Loggers>
    
    </configuration>

由于使用了<asyncLogger>，如果要打印出代码行号和方法名，则需要includeLocation="true"，但这样会影响性能。这几个工程的log4j2.xml内容类似，所以只给出一个例子。

**SSO-API**

package com.test.sso.intf;
    
    import java.util.List;
    
    public interface SSODataStore {
    	List<String> getAllActions(long appId, long userId, byte state);
    }

package com.test.sso.intf;
    
    import java.util.List;
    
    public interface SSOServiceProvider {
    	long checkLogin(String userName, String pwd);
    	List<String> fetchActionsAllowed(long appId, long userId);
    	boolean checkAction(long userId, long appId, String actionName);
    }

**SSO-DataStore**

package com.test.sso;
    
    import java.util.ArrayList;
    import java.util.List;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import com.test.sso.intf.SSODataStore;
    
    public class SSODataStoreImpl implements SSODataStore {
      private final static Logger LOG = LoggerFactory.getLogger(SSODataStoreImpl.class);
      public List<String> getAllActions(long appId, long userId, byte state) {
        LOG.info("appId={}, userId={}, state={}", appId, userId, state);
        List<String> actionList = new ArrayList<>();
        actionList.add("gate_login");
        actionList.add("gate_logout");
        actionList.add("gate_heartbeat");
        return actionList;
      }
    }

package com.test.sso;
    
    import java.io.IOException;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class App {
      public static void main(String[] args) throws IOException {
        System.setProperty("java.net.preferIPv4Stack", "true");
        System.setProperty("dubbo.application.logger", "slf4j");
        // System.setProperty("log4j2.contextSelector", "org.apache.logging.log4j.core.async.AsyncLoggerContextSelector");
    
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("sso-service-dataStore.xml");
        context.start();
        System.in.read();
      }
    }

其中需要注意的是如下这行代码

> ***System.setProperty("dubbo.application.logger", "slf4j");***

它将使dubbo采用slf4j作为底层日志API。可以在org.apache.dubbo.common.logger.LoggerFactory中查看到源码。

sso-service-dataStore.xml

此应用执行时，可以使用-Dservice.port=XXXX的方式覆盖此配置文件中设置的端口号。由于qos暂时用不到，将其禁用，防止端口冲突。

**SSO-ServiceProvider**

package com.test.sso;
    
    import java.util.List;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import com.test.sso.intf.SSODataStore;
    import com.test.sso.intf.SSOServiceProvider;
    
    public class SSOServiceProviderImpl implements SSOServiceProvider {
      private final static Logger LOG = LoggerFactory.getLogger(SSOServiceProviderImpl.class);
      private SSODataStore dataStore;
    
      public void setDataStore(SSODataStore dataStore) {
        this.dataStore = dataStore;
      }
    
      public long checkLogin(String userName, String pwd) {
        LOG.info("userName={}, pwd={}", userName, pwd);
        return 1001;
      }
    
      public List<String> fetchActionsAllowed(long appId, long userId) {
        LOG.info("appId={}, userId={}", appId, userId);
        return dataStore.getAllActions(appId, userId, (byte) 2);
      }
    
      public boolean checkAction(long userId, long appId, String actionName) {
        LOG.info("userId={}, appI={}, actionName={}", userId, appId, actionName);
        return true;
      }
    }

package com.test.sso;
    
    import java.io.IOException;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class App {
      public static void main(String[] args) throws IOException {
        System.setProperty("java.net.preferIPv4Stack", "true");
        System.setProperty("dubbo.application.logger", "slf4j");
    
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("sso-service-provider.xml");
        context.start();
    
        System.in.read();
      }
    }

sso-service-provider.xml

**SSO-Consumer**

package com.test.sso;
    
    import java.util.List;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    import com.test.sso.intf.SSOServiceProvider;
    
    public class App {
      public static void main(String[] args) {
        System.setProperty("dubbo.application.logger", "slf4j");
    
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("sso-service-consumer.xml");
        context.start();
    
        SSOServiceProvider ssoService = (SSOServiceProvider) context.getBean("SSOServiceProvider");
    
        boolean ret = ssoService.checkAction(1001L, 1, "actionName");
        System.out.println(ret);
    
        long userId = ssoService.checkLogin("xl", "12345678");
        System.out.println(userId);
    
        long appId = 1;
        List<String> actionsAllowed = ssoService.fetchActionsAllowed(appId, userId);
        System.out.println(actionsAllowed);
      }
    }

sso-service-consumer.xml

可以使用如下命令分别启动zookeeper服务器和客户端：

> zkServer.cmd
> 
> zkCli.cmd -server 127.0.0.1:2181

然后，启动SSO-DataStore和SSO-ServiceProvider，最后启动SSO-Consumer就可以看到执行结果。

如果想启用dubbo-admin，可以使用如下命令下载并安装dubbo-admin

> git clone https://github.com/apache/incubator-dubbo-admin.git  
> cd incubator-dubbo-admin  
> mvn clean package  
> cd dubbo-admin-distribution/target  
> java -jar dubbo-admin-0.1.jar

访问方式：[http://localhost:8080][http_localhost_8080]

**参考文档**

[Quick start][]  
[incubator-dubbo][]  
[incubator-dubbo-admin][]  
[dubbo一些你不一定知道但是很好用的功能][dubbo]

[http_localhost_8080]: http://localhost:8080
[Quick start]: http://dubbo.apache.org/en-us/docs/user/quick-start.html
[incubator-dubbo]: https://github.com/apache/incubator-dubbo
[incubator-dubbo-admin]: https://github.com/apache/incubator-dubbo-admin
[dubbo]: https://www.jianshu.com/p/ab2afef2b279