Dubbo的基本使用與高級應(yīng)用

本篇是Dubbo的使用篇诲锹，為后續(xù)的源碼分析打基礎(chǔ)牙捉。

1. 最簡單的使用

開篇用一個(gè)最簡單的例子搞监，來介紹如何用Dubbo搭建一個(gè)簡單的例子。

本例包括:

注冊中心(用Zookeeper代替)
服務(wù)提供者(provider)
服務(wù)消費(fèi)者(consumer)
接口(interface)

1.1 項(xiàng)目結(jié)構(gòu)

創(chuàng)建項(xiàng)目蓝角，并創(chuàng)建三個(gè)Module，項(xiàng)目結(jié)構(gòu)如下:

項(xiàng)目結(jié)構(gòu)

1.2 項(xiàng)目依賴

整體pom.xml為:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>Study</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>consumer</module>
        <module>provider</module>
        <module>interface</module>
    </modules>

    <properties>
        <spring-boot.version>2.3.1.RELEASE</spring-boot.version>
        <dubbo.version>2.7.5</dubbo.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <!-- Spring Boot -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <!-- Apache Dubbo  -->
            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-dependencies-bom</artifactId>
                <version>${dubbo.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo</artifactId>
                <version>${dubbo.version}</version>
                <exclusions>
                    <exclusion>
                        <groupId>org.springframework</groupId>
                        <artifactId>spring</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>javax.servlet</groupId>
                        <artifactId>servlet-api</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>log4j</groupId>
                        <artifactId>log4j</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
        </dependencies>
    </dependencyManagement>

</project>

consumer的依賴為:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>Study</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>consumer</artifactId>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>

        <dependency>
            <groupId>org.example</groupId>
            <artifactId>interface</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

        <!-- Dubbo Spring Boot Starter -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
            <version>2.7.5</version>
        </dependency>

        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- Zookeeper dependencies -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-dependencies-zookeeper</artifactId>
            <version>${dubbo.version}</version>
            <type>pom</type>
            <exclusions>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-rpc-http</artifactId>
            <version>${dubbo.version}</version>
        </dependency>

    </dependencies>


</project>

interface的依賴為:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>Study</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>interface</artifactId>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

provider的依賴為:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>Study</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>provider</artifactId>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>org.example</groupId>
            <artifactId>interface</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

        <!-- Dubbo Spring Boot Starter -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
            <version>2.7.5</version>
        </dependency>

        <dependency>
            <groupId>org.jboss.resteasy</groupId>
            <artifactId>resteasy-jaxrs</artifactId>
            <version>3.0.19.Final</version>
        </dependency>

        <dependency>
            <groupId>javax.validation</groupId>
            <artifactId>validation-api</artifactId>
            <version>1.1.0.Final</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
        </dependency>

        <!-- Zookeeper dependencies -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-dependencies-zookeeper</artifactId>
            <version>${dubbo.version}</version>
            <type>pom</type>
            <exclusions>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
            </exclusions>
        </dependency>


        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-rpc-http</artifactId>
            <version>${dubbo.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-metadata-report-zookeeper</artifactId>
            <version>${dubbo.version}</version>
        </dependency>
    </dependencies>

</project>

1.3 具體代碼

1.3.1 服務(wù)提供者

@Service注解暴露服務(wù)

實(shí)現(xiàn)類

package com.zyz.provider.service;

import com.zyz.DemoService;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.config.annotation.Service;
import org.apache.dubbo.rpc.RpcContext;

@Service(version = "default")
public class DefaultDemoService implements DemoService {

    @Override
    public String sayHello(String name) {
        System.out.println("執(zhí)行了服務(wù)" + name);

        URL url = RpcContext.getContext().getUrl();
        return String.format("%s：%s, Hello, %s", url.getProtocol(), url.getPort(), name);  // 正常訪問
    }
}

啟動(dòng)類

package com.zyz;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DubboProviderDemo {

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

}

配置文件application.properties:

# Spring boot application
spring.application.name=dubbo-provider-demo
server.port=8081

# Base packages to scan Dubbo Component: @org.apache.dubbo.config.annotation.Service
dubbo.scan.base-packages=com.zyz.provider.service
dubbo.application.name=${spring.application.name}


## Dubbo Registry
dubbo.registry.address=zookeeper://127.0.0.1:2181

# Dubbo Protocol
dubbo.protocol.name=dubbo
dubbo.protocol.port=20880

日志文件log4j.properties:

###set log levels###
log4j.rootLogger=info, stdout
###output to the console###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=[%d{dd/MM/yy HH:mm:ss:SSS z}] %t %5p %c{2}: %m%n

1.3.2 接口

接口類DemoService:

package com.zyz;

public interface DemoService {

    String sayHello(String name);

}

1.3.3 服務(wù)消費(fèi)者

@Reference引入服務(wù)饭冬，加入版本表示具體引入哪一個(gè)實(shí)現(xiàn)類的實(shí)例

啟動(dòng)類:

package com.zyz;

import org.apache.dubbo.config.annotation.Reference;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;

@SpringBootApplication
public class DubboConsumerDemo {

    @Reference(version = "default")
    private DemoService demoService;

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(DubboConsumerDemo.class);

        DemoService demoService = context.getBean(DemoService.class);
        System.out.println((demoService.sayHello("zyz")));
    }

}

配置文件application.yml:

spring:
  application:
    name: dubbo-consumer-demo

server:
  port: 8082

dubbo:
  registry:
    address: zookeeper://127.0.0.1:2181

Zookeeper的配置參考

先啟動(dòng)Zookeeper使鹅，再啟動(dòng)provider的啟動(dòng)類，最后啟動(dòng)consumer的啟動(dòng)類

看到輸出:

dubbo：20880, Hello, zyz

大功告成昌抠。

2. 具體應(yīng)用

2.1 負(fù)載均衡

Dubbo提供了四種負(fù)載均衡策略患朱，也可以自定義。

Random LoadBalance:隨機(jī)炊苫，按權(quán)重設(shè)置隨機(jī)概率裁厅。
RoundRobin LoadBalance:輪詢冰沙，按公約后的權(quán)重設(shè)置輪詢比率。
LeastActive LoadBalance:最少活躍調(diào)用數(shù)执虹，相同活躍數(shù)的隨機(jī)倦淀，活躍數(shù)指調(diào)用前后計(jì)數(shù)差。
ConsistentHash LoadBalance:一致性 Hash声畏，相同參數(shù)的請求總是發(fā)到同一提供者撞叽。

2.2 具體代碼

修改provider的配置文件為:

# Spring boot application
spring.application.name=dubbo-provider-demo
server.port=8081

# Base packages to scan Dubbo Component: @org.apache.dubbo.config.annotation.Service
dubbo.scan.base-packages=com.zyz.provider.service
dubbo.application.name=${spring.application.name}


## Dubbo Registry
dubbo.registry.address=zookeeper://127.0.0.1:2181

# Dubbo Protocol
#dubbo.protocol.name=dubbo
#dubbo.protocol.port=20880

dubbo.protocols.p1.id=dubbo1
dubbo.protocols.p1.name=dubbo
dubbo.protocols.p1.port=20881
dubbo.protocols.p1.host=0.0.0.0

dubbo.protocols.p2.id=dubbo2
dubbo.protocols.p2.name=dubbo
dubbo.protocols.p2.port=20882
dubbo.protocols.p2.host=0.0.0.0

dubbo.protocols.p3.id=dubbo3
dubbo.protocols.p3.name=dubbo
dubbo.protocols.p3.port=20883
dubbo.protocols.p3.host=0.0.0.0

服務(wù)消費(fèi)端新增類:

package com.zyz.consumer;

import com.zyz.DemoService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.ConfigurableApplicationContext;

@EnableAutoConfiguration
public class LoadBalanceDubboConsumerDemo {

    @Reference(version = "default", loadbalance = "roundrobin")
    private DemoService demoService;

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(LoadBalanceDubboConsumerDemo.class);

        DemoService demoService = context.getBean(DemoService.class);

        roundRobin(demoService);

    }

    /**
     * 負(fù)載均衡(輪詢)
     * @param demoService
     */
    public static void roundRobin(DemoService demoService){

        for (int i = 0; i < 1000; i++) {
            System.out.println((demoService.sayHello("zyz")));
            try {
                Thread.sleep(1 * 1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

}

最終輸出為:

dubbo：20882, Hello, zyz
dubbo：20883, Hello, zyz
dubbo：20881, Hello, zyz
dubbo：20882, Hello, zyz
dubbo：20883, Hello, zyz
dubbo：20881, Hello, zyz

2.2 服務(wù)超時(shí)

2.2.1 說明

在服務(wù)提供者和服務(wù)消費(fèi)者上都可以配置服務(wù)超時(shí)時(shí)間，這兩者是不?樣的插龄。

消費(fèi)者調(diào)??個(gè)服務(wù)愿棋，分為三步:

消費(fèi)者發(fā)送請求（?絡(luò)傳輸）
服務(wù)端執(zhí)?服務(wù)
服務(wù)端返回響應(yīng)（?絡(luò)傳輸）

如果在服務(wù)端和消費(fèi)端只在其中??配置了timeout，那么沒有歧義均牢，表示消費(fèi)端調(diào)?服務(wù)的超時(shí)時(shí)間糠雨，消費(fèi)端如果超過時(shí)間還沒有收到響應(yīng)結(jié)果，則消費(fèi)端會(huì)拋超時(shí)異常徘跪，但甘邀，服務(wù)端不會(huì)拋異常，服務(wù)端在執(zhí)? 服務(wù)后垮庐，會(huì)檢查執(zhí)?該服務(wù)的時(shí)間松邪，如果超過timeout，則會(huì)打印?個(gè)超時(shí)?志哨查。服務(wù)會(huì)正常的執(zhí)?完逗抑。

如果在服務(wù)端和消費(fèi)端各配了?個(gè)timeout，那就?較復(fù)雜了寒亥，假設(shè)

服務(wù)執(zhí)?為5s
消費(fèi)端timeout=3s
服務(wù)端timeout=6s

那么消費(fèi)端調(diào)?服務(wù)時(shí)邮府，消費(fèi)端會(huì)收到超時(shí)異常（因?yàn)橄M(fèi)端超時(shí)了），服務(wù)端?切正常（服務(wù)端沒有超時(shí)）溉奕。

2.2.2 具體代碼

服務(wù)提供方新增兩個(gè)類:

package com.zyz.provider.service;


import com.zyz.DemoService;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.config.annotation.Service;
import org.apache.dubbo.rpc.RpcContext;

import java.util.concurrent.TimeUnit;


@Service(version = "timeout", timeout = 6000)
public class TimeoutDemoService implements DemoService {

    @Override
    public String sayHello(String name) {
        System.out.println("執(zhí)行了timeout服務(wù)" + name);

        // 服務(wù)執(zhí)行5秒
        // 服務(wù)超時(shí)時(shí)間為3秒褂傀，但是執(zhí)行了5秒，服務(wù)端會(huì)把任務(wù)執(zhí)行完的
        // 服務(wù)的超時(shí)時(shí)間加勤，是指如果服務(wù)執(zhí)行時(shí)間超過了指定的超時(shí)時(shí)間則會(huì)拋一個(gè)warn
        try {
            TimeUnit.SECONDS.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println("執(zhí)行結(jié)束" + name);

        URL url = RpcContext.getContext().getUrl();
        return String.format("%s：%s, Hello, %s", url.getProtocol(), url.getPort(), name);  // 正常訪問
    }

}

package com.zyz;

import org.apache.dubbo.config.spring.ServiceBean;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.stereotype.Component;

@Component
public class UpdateBeanPostProcessors implements BeanPostProcessor {

    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {

        if (beanName.contains("ServiceBean")) {
            //這里設(shè)置id仙辟，否則會(huì)造成同一個(gè)Service有多個(gè)group時(shí)，只能注入第一個(gè)service
            ServiceBean serviceBean = (ServiceBean) bean;
            serviceBean.setId(beanName);
        }
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        return bean;
    }
}

消費(fèi)方新增一個(gè)啟動(dòng)類:

package com.zyz.consumer;

import com.zyz.DemoService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.ConfigurableApplicationContext;

import java.io.IOException;

@EnableAutoConfiguration
public class TimeoutDubboConsumerDemo {


    @Reference(version = "timeout", timeout = 3000)
    private DemoService demoService;

    public static void main(String[] args) throws IOException {
        ConfigurableApplicationContext context = SpringApplication.run(TimeoutDubboConsumerDemo.class);

        DemoService demoService = context.getBean(DemoService.class);

        // 服務(wù)調(diào)用超時(shí)時(shí)間為1秒胸竞，默認(rèn)為3秒
        // 如果這1秒內(nèi)沒有收到服務(wù)結(jié)果欺嗤，則會(huì)報(bào)錯(cuò)
        System.out.println((demoService.sayHello("周瑜"))); //xxservestub


    }

}

2.3 集群容錯(cuò)

集群容錯(cuò)表示：服務(wù)消費(fèi)者在調(diào)?某個(gè)服務(wù)時(shí)，這個(gè)服務(wù)有多個(gè)服務(wù)提供者卫枝，在經(jīng)過負(fù)載均衡后選出其中 ?個(gè)服務(wù)提供者之后進(jìn)?調(diào)?煎饼，但調(diào)?報(bào)錯(cuò)后，Dubbo所采取的后續(xù)處理策略校赤。

2.3.1 設(shè)置

Failover Cluster:默認(rèn)配置吆玖，重試兩次筒溃，一共請求三次
Failfast Cluster:快速失敗，只發(fā)起一次調(diào)用沾乘，失敗立即報(bào)錯(cuò)怜奖。通常用于非冪等性的寫操作，比如新增記錄
Failsafe Cluster:失敗安全翅阵，出現(xiàn)異常時(shí)歪玲，直接忽略。通常用于寫入審計(jì)日志等操作
Failback Cluster:失敗自動(dòng)恢復(fù)掷匠，后臺記錄失敗請求滥崩，定時(shí)重發(fā)。通常用于消息通知操作
Forking Cluster:并行調(diào)用多個(gè)服務(wù)器讹语，只要一個(gè)成功即返回钙皮。通常用于實(shí)時(shí)性要求較高的讀操作，但需要浪費(fèi)更多服務(wù)資源顽决《烫酰可通過 forks="2" 來設(shè)置最大并行數(shù)。
Broadcast Cluster:廣播調(diào)用所有提供者才菠，逐個(gè)調(diào)用茸时，任意一臺報(bào)錯(cuò)則報(bào)錯(cuò)。通常用于通知所有提供者更新緩存或日志等本地資源信息鸠儿。

2.3.2 具體代碼

cousumer新增一個(gè)類:

package com.zyz.consumer;

import com.zyz.DemoService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.ConfigurableApplicationContext;

import java.io.IOException;

@EnableAutoConfiguration
public class ClusterDubboConsumerDemo {


    @Reference(version = "cluster", timeout = 1000, cluster = "failfast")
    private DemoService demoService;

    public static void main(String[] args) throws IOException {
        ConfigurableApplicationContext context = SpringApplication.run(ClusterDubboConsumerDemo.class);

        DemoService demoService = context.getBean(DemoService.class);

        System.out.println((demoService.sayHello("zyz")));

    }

}

provider新增一個(gè)實(shí)現(xiàn)類:

package com.zyz.provider.service;

import com.zyz.DemoService;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.config.annotation.Service;
import org.apache.dubbo.rpc.RpcContext;

import java.util.concurrent.TimeUnit;

@Service(version = "cluster", timeout = 3000)
public class ClusterDemoService implements DemoService {

    @Override
    public String sayHello(String name) {
        System.out.println("執(zhí)行了cluster服務(wù)" + name);

        try {
            TimeUnit.SECONDS.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println("執(zhí)行結(jié)束" + name);
        URL url = RpcContext.getContext().getUrl();
        return String.format("%s：%s, Hello, %s", url.getProtocol(), url.getPort(), name);  // 正常訪問
    }
}

2.4 服務(wù)降級

服務(wù)降級表示：服務(wù)消費(fèi)者在調(diào)?某個(gè)服務(wù)提供者時(shí)屹蚊，如果該服務(wù)提供者報(bào)錯(cuò)了，所采取的措施进每。

集群容錯(cuò)和服務(wù)降級的區(qū)別在于：

集群容錯(cuò)是整個(gè)集群范圍內(nèi)的容錯(cuò)
服務(wù)降級是單個(gè)服務(wù)提供者的?身容錯(cuò)

2.4.1 具體代碼

consumer新增一個(gè)類:

package com.zyz.consumer;

import com.zyz.DemoService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.ConfigurableApplicationContext;

import java.io.IOException;

@EnableAutoConfiguration
public class MockDubboConsumerDemo {


    @Reference(version = "timeout", timeout = 1000, mock = "fail: return 123")
    private DemoService demoService;

    public static void main(String[] args) throws IOException {
        ConfigurableApplicationContext context = SpringApplication.run(MockDubboConsumerDemo.class);

        DemoService demoService = context.getBean(DemoService.class);

        System.out.println((demoService.sayHello("zyz")));
    }

}

2.5 本地存根

本地存根就是?段邏輯，這段邏輯是在服務(wù)消費(fèi)端執(zhí)?的命斧，這段邏輯?般都是由服務(wù)提供者提供田晚，服務(wù)提供者可以利?這種機(jī)制在服務(wù)消費(fèi)者遠(yuǎn)程調(diào)?服務(wù)提供者之前或之后再做?些其他事情，?如結(jié)果緩存国葬，請求參數(shù)驗(yàn)證等等贤徒。(AOP功能)

2.5.1 具體代碼

interface新增一個(gè)類:

package com.zyz;

public class DemoServiceStub implements DemoService {

    private final DemoService demoService;

    // 構(gòu)造函數(shù)傳入真正的遠(yuǎn)程代理對象
    public DemoServiceStub(DemoService demoService){
        this.demoService = demoService;
    }

    @Override
    public String sayHello(String name) {
        // 此代碼在客戶端執(zhí)行, 你可以在客戶端做ThreadLocal本地緩存，或預(yù)先驗(yàn)證參數(shù)是否合法汇四，等等
        try {
            System.out.println("校驗(yàn)邏輯");
            return demoService.sayHello(name); // safe  null
        } catch (Exception e) {
            // 你可以容錯(cuò)接奈，可以做任何AOP攔截事項(xiàng)
            return "容錯(cuò)數(shù)據(jù)";
        }
    }
}

consumer新增一個(gè)類:

package com.zyz.consumer;

import com.zyz.DemoService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.ConfigurableApplicationContext;

import java.io.IOException;

@EnableAutoConfiguration
public class StubDubboConsumerDemo {


    @Reference(version = "timeout", timeout = 1000, stub = "com.zyz.DemoServiceStub")
    private DemoService demoService;

    public static void main(String[] args) throws IOException {
        ConfigurableApplicationContext context = SpringApplication.run(StubDubboConsumerDemo.class);

        DemoService demoService = context.getBean(DemoService.class);

        System.out.println((demoService.sayHello("周瑜")));


    }

}

2.6 本地偽裝

就是Mock功能，Mock其實(shí)就是Dubbo中的服務(wù)容錯(cuò)的解決?案通孽。

2.7 參數(shù)回調(diào)

?先序宦，如果當(dāng)前服務(wù)?持參數(shù)回調(diào)，意思就是：對于某個(gè)服務(wù)接?中的某個(gè)?法背苦，如果想?持消費(fèi)者在調(diào) ?這個(gè)?法時(shí)能設(shè)置回調(diào)邏輯互捌，那么該?法就需要提供?個(gè)?參?來表示回調(diào)邏輯潘明。

因?yàn)镈ubbo協(xié)議是基于?連接的，所以消費(fèi)端在兩次調(diào)?同?個(gè)?法時(shí)想指定不同的回調(diào)邏輯秕噪，那么就需要在調(diào)?時(shí)在指定?定key進(jìn)?區(qū)分钳降。

2.7.1 參數(shù)回調(diào)

consumer新增兩個(gè)類

package com.zyz.consumer;


import com.zyz.DemoServiceListener;

public class DemoServiceListenerImpl implements DemoServiceListener {

    @Override
    public void changed(String msg) {
        System.out.println("被回調(diào)了："+msg);
    }
}

package com.zyz.consumer;

import com.zyz.DemoService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.ConfigurableApplicationContext;

import java.io.IOException;

@EnableAutoConfiguration
public class CallbackDubboConsumerDemo {


    @Reference(version = "callback")
    private DemoService demoService;

    public static void main(String[] args) throws IOException {
        ConfigurableApplicationContext context = SpringApplication.run(CallbackDubboConsumerDemo.class);

        DemoService demoService = context.getBean(DemoService.class);

        // 用來進(jìn)行callback
        System.out.println(demoService.sayHello("zyz", "d1", new DemoServiceListenerImpl()));
        System.out.println(demoService.sayHello("zyz", "d2", new DemoServiceListenerImpl()));
        System.out.println(demoService.sayHello("zyz", "d3", new DemoServiceListenerImpl()));
    }

}

interface新增一個(gè)類，并在DemoService中新增方法:

package com.zyz;

public interface DemoService {

    String sayHello(String name);

    // 添加回調(diào)
    default String sayHello(String name, String key, DemoServiceListener listener) {
        return null;
    };

}

package com.zyz;

public interface DemoServiceListener {
    void changed(String msg);
}

provider新增類:

package com.zyz.provider.service;

import com.zyz.DemoService;
import com.zyz.DemoServiceListener;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.config.annotation.Argument;
import org.apache.dubbo.config.annotation.Method;
import org.apache.dubbo.config.annotation.Service;
import org.apache.dubbo.rpc.RpcContext;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;


// DemoService的sayHello方法的index=1的參數(shù)是回調(diào)對象腌巾，服務(wù)消費(fèi)者可以調(diào)用addListener方法來添加回調(diào)對象遂填，服務(wù)提供者一旦執(zhí)行回調(diào)對象的方法就會(huì)通知給服務(wù)消費(fèi)者

@Service(version = "callback", methods = {@Method(name = "sayHello", arguments = {@Argument(index = 2, callback = true)})}, callbacks = 3)
public class CallBackDemoService implements DemoService {

    private final Map<String, DemoServiceListener> listeners = new ConcurrentHashMap<String, DemoServiceListener>();

    public CallBackDemoService() {
        Thread t = new Thread(new Runnable() {
            @Override
            public void run() {
                while (true) {
                    for (Map.Entry<String, DemoServiceListener> entry : listeners.entrySet()) {
                        entry.getValue().changed(getChanged(entry.getKey()));
                    }
                    try {
                        Thread.sleep(5000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        });

        t.start();

    }


    private String getChanged(String key) {
        return "Changed: " + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
    }

    @Override
    public String sayHello(String name) {
        return null;
    }

    @Override
    public String sayHello(String name, String key, DemoServiceListener callback) {
        System.out.println("執(zhí)行了回調(diào)服務(wù)" + name);

        listeners.put(key, callback);
        URL url = RpcContext.getContext().getUrl();
        return String.format("%s：%s, Hello, %s", url.getProtocol(), url.getPort(), name);  // 正常訪問
    }

}

2.8 異步調(diào)用

從 2.7.0 開始，Dubbo 的所有異步編程接口開始以 CompletableFuture 為基礎(chǔ)

基于 NIO 的非阻塞實(shí)現(xiàn)并行調(diào)用澈蝙，客戶端不需要啟動(dòng)多線程即可完成并行調(diào)用多個(gè)遠(yuǎn)程服務(wù)吓坚，相對多線程開銷較小。

2.8.1 具體代碼

consumer新增類:

package com.zyz.consumer;

import com.zyz.DemoService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.ConfigurableApplicationContext;

import java.io.IOException;
import java.util.concurrent.CompletableFuture;

@EnableAutoConfiguration
public class AsyncDubboConsumerDemo {

    @Reference(version = "async")
    private DemoService demoService;

    public static void main(String[] args) throws IOException {
        ConfigurableApplicationContext context = SpringApplication.run(AsyncDubboConsumerDemo.class);

        DemoService demoService = context.getBean(DemoService.class);

        // 調(diào)用直接返回CompletableFuture
        CompletableFuture<String> future = demoService.sayHelloAsync("異步調(diào)用");  // 5

        future.whenComplete((v, t) -> {
            if (t != null) {
                t.printStackTrace();
            } else {
                System.out.println("Response: " + v);
            }
        });

        System.out.println("結(jié)束了");

    }

}

interface中DemoService新增方法:

package com.zyz;

import java.util.concurrent.CompletableFuture;

public interface DemoService {

    String sayHello(String name);

    // 異步調(diào)用方法
    default CompletableFuture<String> sayHelloAsync(String name) {
        return null;
    };

    // 添加回調(diào)
    default String sayHello(String name, String key, DemoServiceListener listener) {
        return null;
    };

}

consumer新增一個(gè)類:

package com.zyz.provider.service;

import com.zyz.DemoService;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.config.annotation.Service;
import org.apache.dubbo.rpc.RpcContext;

import java.util.concurrent.CompletableFuture;

@Service(version = "async")
public class AsyncDemoService implements DemoService {

    @Override
    public String sayHello(String name) {
        System.out.println("執(zhí)行了同步服務(wù)" + name);
        URL url = RpcContext.getContext().getUrl();
        return String.format("%s：%s, Hello, %s", url.getProtocol(), url.getPort(), name);  // 正常訪問
    }

    @Override
    public CompletableFuture<String> sayHelloAsync(String name) {
        System.out.println("執(zhí)行了異步服務(wù)" + name);

        return CompletableFuture.supplyAsync(() -> {
            return sayHello(name);
        });
    }
}

2.9 泛化調(diào)用

泛化調(diào)?可以?來做服務(wù)測試碉克。

在Dubbo中凌唬，如果某個(gè)服務(wù)想要?持泛化調(diào)?，就可以將該服務(wù)的generic屬性設(shè)置為true漏麦，那對于服務(wù)消費(fèi)者來說客税，就可以不?依賴該服務(wù)的接?，直接利?GenericService接?來進(jìn)?服務(wù)調(diào)?撕贞。

2.9.1 具體代碼

consumer新增一個(gè)類:

package com.zyz.consumer;

import org.apache.dubbo.config.annotation.Reference;
import org.apache.dubbo.rpc.service.GenericService;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.ConfigurableApplicationContext;

import java.io.IOException;

@EnableAutoConfiguration
public class GenericDubboConsumerDemo {


    @Reference(id = "demoService", version = "default", interfaceName = "com.zyz.DemoService", generic = true)
    private GenericService genericService;

    public static void main(String[] args) throws IOException {
        ConfigurableApplicationContext context = SpringApplication.run(GenericDubboConsumerDemo.class);

        GenericService genericService = (GenericService) context.getBean("demoService");

        Object result = genericService.$invoke("sayHello", new String[]{"java.lang.String"}, new Object[]{"zyz"});
        System.out.println(result);


    }

}

provider新增一個(gè)類:

package com.zyz.provider.service;

import org.apache.dubbo.config.annotation.Service;
import org.apache.dubbo.rpc.service.GenericException;
import org.apache.dubbo.rpc.service.GenericService;

@Service(interfaceName = "com.zyz.DemoService", version = "generic")
public class GenericDemoService implements GenericService {
    @Override
    public Object $invoke(String s, String[] strings, Object[] objects) throws GenericException {
        System.out.println("執(zhí)行了generic服務(wù)");

        return "執(zhí)行的方法是" + s;
    }
}

3. 相關(guān)工具

Zookeeper可視化客戶端
 管理臺

?著作權(quán)歸作者所有,轉(zhuǎn)載或內(nèi)容合作請聯(lián)系作者

人面猴
序言：七十年代末更耻，一起剝皮案震驚了整個(gè)濱河市，隨后出現(xiàn)的幾起案子捏膨，更是在濱河造成了極大的恐慌秧均，老刑警劉巖，帶你破解...
沈念sama閱讀 216,372評論 6贊 498
死咒
序言：濱河連續(xù)發(fā)生了三起死亡事件号涯，死亡現(xiàn)場離奇詭異目胡，居然都是意外死亡，警方通過查閱死者的電腦和手機(jī)链快，發(fā)現(xiàn)死者居然都...
沈念sama閱讀 92,368評論 3贊 392
救了他兩次的神仙讓他今天三更去死
文/潘曉璐我一進(jìn)店門誉己，熙熙樓的掌柜王于貴愁眉苦臉地迎上來，“玉大人域蜗，你說我怎么就攤上這事巨双。” “怎么了霉祸？”我有些...
開封第一講書人閱讀 162,415評論 0贊 353
道士緝兇錄：失蹤的賣姜人
文/不壞的土叔我叫張陵筑累，是天一觀的道長。經(jīng)常有香客問我丝蹭，道長慢宗，這世上最難降的妖魔是什么？我笑而不...
開封第一講書人閱讀 58,157評論 1贊 292
?港島之戀（遺憾婚禮）
正文為了忘掉前任，我火速辦了婚禮婆廊，結(jié)果婚禮上迅细，老公的妹妹穿的比我還像新娘。我一直安慰自己淘邻，他們只是感情好茵典，可當(dāng)我...
茶點(diǎn)故事閱讀 67,171評論 6贊 388
惡毒庶女頂嫁案：這布局不是一般人想出來的
文/花漫我一把揭開白布。她就那樣靜靜地躺著宾舅，像睡著了一般统阿。火紅的嫁衣襯著肌膚如雪。梳的紋絲不亂的頭發(fā)上筹我，一...
開封第一講書人閱讀 51,125評論 1贊 297
城市分裂傳說
那天扶平，我揣著相機(jī)與錄音，去河邊找鬼蔬蕊。笑死结澄，一個(gè)胖子當(dāng)著我的面吹牛，可吹牛的內(nèi)容都是我干的麻献。我是一名探鬼主播旅赢，決...
沈念sama閱讀 40,028評論 3贊 417
雙鴛鴦連環(huán)套：你想象不到人心有多黑
文/蒼蘭香墨我猛地睜開眼，長吁一口氣：“原來是場噩夢啊……” “哼雷绢！你這毒婦竟也來了？” 一聲冷哼從身側(cè)響起宇立，我...
開封第一講書人閱讀 38,887評論 0贊 274
萬榮殺人案實(shí)錄
序言：老撾萬榮一對情侶失蹤他去，失蹤者是張志新（化名）和其女友劉穎媳搪，沒想到半個(gè)月后展运，有當(dāng)?shù)厝嗽跇淞掷锇l(fā)現(xiàn)了一具尸體精刷，經(jīng)...
沈念sama閱讀 45,310評論 1贊 310
?護(hù)林員之死
正文獨(dú)居荒郊野嶺守林人離奇死亡拗胜，尸身上長有42處帶血的膿包…… 初始之章·張勛以下內(nèi)容為張勛視角年9月15日...
茶點(diǎn)故事閱讀 37,533評論 2贊 332
?白月光啟示錄
正文我和宋清朗相戀三年，在試婚紗的時(shí)候發(fā)現(xiàn)自己被綠了怒允。大學(xué)時(shí)的朋友給我發(fā)了我未婚夫和他白月光在一起吃飯的照片埂软。...
茶點(diǎn)故事閱讀 39,690評論 1贊 348
活死人
序言：一個(gè)原本活蹦亂跳的男人離奇死亡，死狀恐怖纫事，靈堂內(nèi)的尸體忽然破棺而出勘畔，到底是詐尸還是另有隱情，我是刑警寧澤丽惶，帶...
沈念sama閱讀 35,411評論 5贊 343
?日本核電站爆炸內(nèi)幕
正文年R本政府宣布炫七，位于F島的核電站，受9級特大地震影響钾唬，放射性物質(zhì)發(fā)生泄漏万哪。R本人自食惡果不足惜侠驯，卻給世界環(huán)境...
茶點(diǎn)故事閱讀 41,004評論 3贊 325
男人毒藥：我在死后第九天來索命
文/蒙蒙一、第九天我趴在偏房一處隱蔽的房頂上張望奕巍。院中可真熱鬧吟策，春花似錦、人聲如沸的止。這莊子的主人今日做“春日...
開封第一講書人閱讀 31,659評論 0贊 22
一樁弒父案，背后竟有這般陰謀
文/蒼蘭香墨我抬頭看了看天上的太陽冲杀。三九已至效床，卻和暖如春，著一層夾襖步出監(jiān)牢的瞬間权谁，已是汗流浹背剩檀。一陣腳步聲響...
開封第一講書人閱讀 32,812評論 1贊 268
情欲美人皮
我被黑心中介騙來泰國打工，沒想到剛下飛機(jī)就差點(diǎn)兒被人妖公主榨干…… 1. 我叫王不留旺芽，地道東北人沪猴。一個(gè)月前我還...
沈念sama閱讀 47,693評論 2贊 368
代替公主和親
正文我出身青樓魏蔗，卻偏偏與公主長得像焕参，于是被迫代替她去往敵國和親。傳聞我的和親對象是個(gè)殘疾皇子痹扇，可洞房花燭夜當(dāng)晚...
茶點(diǎn)故事閱讀 44,577評論 2贊 353

Dubbo的基本使用與高級應(yīng)用

1. 最簡單的使用

1.1 項(xiàng)目結(jié)構(gòu)

1.2 項(xiàng)目依賴

1.3 具體代碼

1.3.1 服務(wù)提供者

1.3.2 接口

1.3.3 服務(wù)消費(fèi)者

2. 具體應(yīng)用

2.1 負(fù)載均衡

2.2 具體代碼

2.2 服務(wù)超時(shí)

2.2.1 說明

2.2.2 具體代碼

2.3 集群容錯(cuò)

2.3.1 設(shè)置

2.3.2 具體代碼

2.4 服務(wù)降級

2.4.1 具體代碼

2.5 本地存根

2.5.1 具體代碼

2.6 本地偽裝

2.7 參數(shù)回調(diào)

2.7.1 參數(shù)回調(diào)

2.8 異步調(diào)用

2.8.1 具體代碼

2.9 泛化調(diào)用

2.9.1 具體代碼

3. 相關(guān)工具

推薦閱讀更多精彩內(nèi)容