dubbo 尝试

封面《golden marriage》

dubbo

Dubbo 是阿里开发的一个 RPC 服务框架，用于解决微服务架构下的服务治理与通信问题。后来捐献给了 Apache，现在是 Apache Dubbo。

dubbo 架构

节点	说明
Provider	暴露服务的服务提供方
Consumer	调用远程服务的服务消费方
Registry	服务注册与发现的注册中心
Monitor	统计服务的调用次数和调用时间的监控中心
Container	服务运行容器

0. 服务容器负责启动，加载，运行服务提供者。
1. 服务提供者在启动时，向注册中心注册自己提供的服务。
2. 服务消费者在启动时，向注册中心订阅自己所需的服务。
3. 注册中心返回服务提供者地址列表给消费者，如果有变更，注册中心将基于长连接推送变更数据给消费者。
4. 服务消费者，从提供者地址列表中，基于软负载均衡算法，选一台提供者进行调用，如果调用失败，再选另一台调用。
5. 服务消费者和提供者，在内存中累计调用次数和调用时间，定时每分钟发送一次统计数据到监控中心。

demo 结构

在这次 demo 的结构如下，通过 tree 命令输出如下。其中 dubbo-demo-api 是服务提供端和消费端公用的 api，dubbo-demo-consumer 和 dubbo-demo-provider 分别是服务的消费端和提供端

│  .gitignore
│  pom.xml
├─dubbo-demo-api
│  │  pom.xml
│  │
│  └─src
│      └─main
│          └─java
│              └─com
│                  └─qxdn
│                      └─demo
│                          └─dubbo
│                              └─api
│                                      HelloService.java
│
├─dubbo-demo-consumer
│  │  pom.xml
│  │
│  └─src
│      └─main
│          ├─java
│          │  └─com
│          │      └─qxdn
│          │          └─demo
│          │              └─dubbo
│          │                  └─consumer
│          │                          ConsumerApplication.java
│          │
│          └─resources
│                  application.yml
│                  log4j.properties
│
└─dubbo-demo-provider
    │  pom.xml
    │
    └─src
        └─main
            ├─java
            │  └─com
            │      └─qxdn
            │          └─demo
            │              └─dubbo
            │                  └─provider
            │                          EmbeddedZooKeeper.java
            │                          HelloServiceImpl.java
            │                          ProviderApplication.java
            │
            └─resources
                    application.yml
                    log4j.properties

父级 POM

...
<groupId>com.qxdn.demo</groupId>
    <artifactId>dubbo-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>pom</packaging>

    <properties>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
        <spring.version>4.3.16.RELEASE</spring.version>
        <dubbo.version>3.0.7</dubbo.version>
        <slf4j-log4j12.version>1.7.25</slf4j-log4j12.version>
        <spring-boot.version>2.7.5</spring-boot.version>
    </properties>

    <modules>
        <module>dubbo-demo-api</module>
        <module>dubbo-demo-provider</module>
        <module>dubbo-demo-consumer</module>
    </modules>

    <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>

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

            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-dependencies-zookeeper</artifactId>
                <version>${dubbo.version}</version>
                <type>pom</type>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j-log4j12.version}</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.24</version>
            <scope>provided</scope>
        </dependency>
...

接口

POM

<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>
        <groupId>com.qxdn.demo</groupId>
        <artifactId>dubbo-demo</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>dubbo-demo-api</artifactId>

    <properties>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
        <skip_maven_deploy>true</skip_maven_deploy>
    </properties>

</project>

接口

// HelloService.java
package com.qxdn.demo.dubbo.api;

import java.util.concurrent.CompletableFuture;

public interface HelloService {

    String sayHello(String name);

    default CompletableFuture<String> sayHelloAsync(String name) {
        return CompletableFuture.completedFuture(sayHello(name));
    }

}

服务提供者

POM

这里使用 zookeeper 作为注册中心

<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>
        <groupId>com.qxdn.demo</groupId>
        <artifactId>dubbo-demo</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>dubbo-demo-provider</artifactId>

    <dependencies>
        <dependency>
            <groupId>com.qxdn.demo</groupId>
            <artifactId>dubbo-demo-api</artifactId>
            <version>${project.parent.version}</version>
        </dependency>
        <!-- dubbo -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-dependencies-zookeeper</artifactId>
            <type>pom</type>
        </dependency>
        <!-- dubbo starter -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
        </dependency>
        <!-- spring starter -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>ch.qos.logback</groupId>
                    <artifactId>logback-classic</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

配置

application.yml

服务注册中心选择自己的 zookeeper 的地址

dubbo:
  application:
    name: dubbo-demo-provider
  protocol:
    name: dubbo
    port: -1
  registry:
    id: zk-registry
    address: zookeeper://127.0.0.1:2181
  config-center:
    address: zookeeper://127.0.0.1:2181
  metadata-report:
    address: zookeeper://127.0.0.1:2181

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

Provider

Impl

这里完成 RPC 服务的实现

//HelloServiceImpl.java
package com.qxdn.demo.dubbo.provider;

import com.qxdn.demo.dubbo.api.HelloService;
import lombok.extern.slf4j.Slf4j;
import org.apache.dubbo.config.annotation.DubboService;
import org.apache.dubbo.rpc.RpcContext;

@Slf4j
@DubboService
public class HelloServiceImpl implements HelloService {

    @Override
    public String sayHello(String name) {
        log.info("Hello " + name + ", request from consumer: " + RpcContext.getServiceContext().getRemoteAddressString());
        return "Hello " + name + "from: "  + RpcContext.getServiceContext().getLocalAddressString();
    }
}

zookeeper

zookeeper 可以到 apache 的官网下载

这里我们使用别人的 embedzookeeper, 源码在 github

Application

package com.qxdn.demo.dubbo.provider;

import lombok.extern.slf4j.Slf4j;
import org.apache.dubbo.config.spring.context.annotation.EnableDubbo;

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


@Slf4j
@SpringBootApplication
@EnableDubbo
public class ProviderApplication {
    public static void main(String[] args) throws Exception {
        new EmbeddedZooKeeper(2181, false).start();

        SpringApplication.run(ProviderApplication.class, args);
        log.info("dubbo service started");
    }
}

服务消费者

POM

这里使用 zookeeper 作为注册中心

<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>
        <groupId>com.qxdn.demo</groupId>
        <artifactId>dubbo-demo</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>dubbo-demo-consumer</artifactId>

    <dependencies>
        <dependency>
            <groupId>com.qxdn.demo</groupId>
            <artifactId>dubbo-demo-api</artifactId>
            <version>${project.parent.version}</version>
        </dependency>
        <!-- dubbo -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-dependencies-zookeeper</artifactId>
            <type>pom</type>
        </dependency>
        <!-- dubbo starter -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
        </dependency>
        <!-- spring starter -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>ch.qos.logback</groupId>
                    <artifactId>logback-classic</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

配置

application.yml

服务注册中心选择自己的 zookeeper 的地址

dubbo:
  application:
    name: dubbo-springboot-demo-consumer
  protocol:
    name: dubbo
    port: -1
  registry:
    id: zk-registry
    address: zookeeper://127.0.0.1:2181
  config-center:
    address: zookeeper://127.0.0.1:2181
  metadata-report:
    address: zookeeper://127.0.0.1:2181

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

Consumer

@DubboReference 中的 loadbalance 是负载均很的方案，这里选择随机，此外注解也可以使用 version 进行服务的过滤

package com.qxdn.demo.dubbo.consumer;

import com.qxdn.demo.dubbo.api.HelloService;
import lombok.extern.slf4j.Slf4j;
import org.apache.dubbo.common.constants.LoadbalanceRules;
import org.apache.dubbo.config.annotation.DubboReference;
import org.apache.dubbo.config.spring.context.annotation.EnableDubbo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.stereotype.Service;

@SpringBootApplication
@Service
@EnableDubbo
@Slf4j
public class ConsumerApplication {

    @DubboReference(loadbalance = LoadbalanceRules.RANDOM)
    private HelloService helloService;

    public static void main(String[] args) {

        ConfigurableApplicationContext context = SpringApplication.run(ConsumerApplication.class, args);
        ConsumerApplication application = context.getBean(ConsumerApplication.class);
        String result = application.doSayHello("java");
        log.info("result: " + result);
    }

    public String doSayHello(String name) {
        return helloService.sayHello(name);
    }
}

效果

服务提供者的输出

...
[20/11/22 03:22:54:208 CST] NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181  INFO server.NIOServerCnxnFactory: Accepted socket connection from /127.0.0.1:51634
[20/11/22 03:22:54:208 CST] NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181  INFO server.ZooKeeperServer: Client attempting to establish new session at /127.0.0.1:51634
[20/11/22 03:22:54:209 CST] SyncThread:0  INFO server.ZooKeeperServer: Established session 0x1000cab1b92000a with negotiated timeout 60000 for client /127.0.0.1:51634
[20/11/22 03:22:54:352 CST] NettyServerWorker-3-9  INFO netty4.NettyServerHandler:  [DUBBO] The connection of /192.168.31.35:51635 -> /192.168.31.35:20880 is established., dubbo version: 3.0.7, current host: 192.168.31.35
[20/11/22 03:22:54:455 CST] NettyServerWorker-3-9  INFO netty4.NettyServerHandler:  [DUBBO] The connection of /192.168.31.35:51635 -> /192.168.31.35:20880 is disconnected., dubbo version: 3.0.7, current host: 192.168.31.35
[20/11/22 03:22:54:493 CST] ProcessThread(sid:0 cport:2181):  INFO server.PrepRequestProcessor: Got user-level KeeperException when processing sessionid:0x1000cab1b92000a type:create cxid:0x3 zxid:0x4e txntype:-1 reqpath:n/a Error Path:/services/dubbo-demo-provider Error:KeeperErrorCode = NodeExists for /services/dubbo-demo-provider
[20/11/22 03:22:55:081 CST] DubboServerHandler-192.168.31.35:20880-thread-25  INFO provider.HelloServiceImpl: Hello java, request from consumer: 192.168.31.35:51631
[20/11/22 03:37:05:560 CST] Dubbo-framework-cache-refreshing-scheduler-thread-1  INFO metadata.AbstractCacheManager$CacheRefreshTask:  [DUBBO] Dumping mapping caches, latest entries 0, dubbo version: 3.0.7, current host: 192.168.31.35

服务消费者的输出

...
2 03:22:54:588 CST] main  INFO metadata.MetadataInfo:  [DUBBO] metadata revision changed: null -> 0ef9521ed22939bb2e1da2ea8012f84d, app: dubbo-springboot-demo-consumer, services: 1, dubbo version: 3.0.7, current host: 192.168.31.35
[20/11/22 03:22:55:063 CST] main  INFO deploy.DefaultApplicationDeployer:  [DUBBO] Dubbo Application[1.1](dubbo-springboot-demo-consumer) is ready., dubbo version: 3.0.7, current host: 192.168.31.35
[20/11/22 03:22:55:068 CST] main  INFO consumer.ConsumerApplication: Started ConsumerApplication in 3.234 seconds (JVM running for 4.244)
[20/11/22 03:22:55:071 CST] pool-1-thread-1  INFO event.AwaitingNonWebApplicationListener:  [Dubbo] Current Spring Boot Application is await...
[20/11/22 03:22:55:084 CST] main  INFO consumer.ConsumerApplication: result: Hello javafrom: 192.168.31.35:20880
[20/11/22 03:32:53:388 CST] Dubbo-framework-cache-refreshing-scheduler-thread-1  INFO metadata.AbstractCacheManager$CacheRefreshTask:  [DUBBO] Dumping mapping caches, latest entries 1, dubbo version: 3.0.7, current host: 192.168.31.35
[20/11/22 03:32:54:201 CST] Dubbo-framework-cache-refreshing-scheduler-thread-1  INFO metadata.AbstractCacheManager$CacheRefreshTask:  [DUBBO] Dumping meta caches, latest entries 1, dubbo version: 3.0.7, current host: 192.168.31.35

可以看到两边都有调用结果的输出

可能的问题

启动程序时候出现问题如下

Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/core/metrics/ApplicationStartup
	at org.springframework.boot.SpringApplication.<init>(SpringApplication.java:251)
	at org.springframework.boot.SpringApplication.<init>(SpringApplication.java:264)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1311)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1300)
	at com.example.simple.dubbo_demo_provider.ProviderApplication.main(ProviderApplication.java:10)
Caused by: java.lang.ClassNotFoundException: org.springframework.core.metrics.ApplicationStartup
	at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 5 more

经过查找资料发现是因为父 POM 的 parent 里是 spring-boot-parent 而且还自定义了 <dependencyManagement/> 使得子模块里找不到对应的依赖 module。

解决方法就是在原先的父 POM<dependencyManagement/> 里面加上

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

SLF4J: Class path contains multiple SLF4J bindings

SLF4J 绑定多个实现

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/C:/Users/qianx/.m2/repository/ch/qos/logback/logback-classic/1.2.11/logback-classic-1.2.11.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/C:/Users/qianx/.m2/repository/org/slf4j/slf4j-log4j12/1.7.25/slf4j-log4j12-1.7.25.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [ch.qos.logback.classic.util.ContextSelectorStaticBinder]

这是因为项目中 SLF4J 有多种实现，可以通过下面的命令或者 IDE 的依赖分析来找到，

mvn dependency:tree

结果如下

# result
[INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ dubbo-demo-provider ---
[INFO] com.qxdn.demo:dubbo-demo-provider:jar:0.0.1-SNAPSHOT
[INFO] +- com.qxdn.demo:dubbo-demo-api:jar:0.0.1-SNAPSHOT:compile
[INFO] +- org.apache.dubbo:dubbo:jar:3.0.7:compile
[INFO] |  +- org.springframework:spring-context:jar:5.3.23:compile
[INFO] |  |  +- org.springframework:spring-aop:jar:5.3.23:compile
[INFO] |  |  +- org.springframework:spring-beans:jar:5.3.23:compile
[INFO] |  |  \- org.springframework:spring-expression:jar:5.3.23:compile
[INFO] |  +- com.alibaba.spring:spring-context-support:jar:1.0.8:compile
[INFO] |  +- org.javassist:javassist:jar:3.28.0-GA:compile
[INFO] |  +- io.netty:netty-all:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-buffer:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-dns:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-haproxy:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-http:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-http2:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-memcache:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-mqtt:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-redis:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-smtp:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-socks:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-stomp:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-codec-xml:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-common:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-handler:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-transport-native-unix-common:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-handler-proxy:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-resolver:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-resolver-dns:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-transport:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-transport-rxtx:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-transport-sctp:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-transport-udt:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-transport-classes-epoll:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-transport-classes-kqueue:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-resolver-dns-classes-macos:jar:4.1.84.Final:compile
[INFO] |  |  +- io.netty:netty-transport-native-epoll:jar:linux-x86_64:4.1.84.Final:runtime
[INFO] |  |  +- io.netty:netty-transport-native-epoll:jar:linux-aarch_64:4.1.84.Final:runtime
[INFO] |  |  +- io.netty:netty-transport-native-kqueue:jar:osx-x86_64:4.1.84.Final:runtime
[INFO] |  |  +- io.netty:netty-transport-native-kqueue:jar:osx-aarch_64:4.1.84.Final:runtime
[INFO] |  |  +- io.netty:netty-resolver-dns-native-macos:jar:osx-x86_64:4.1.84.Final:runtime
[INFO] |  |  \- io.netty:netty-resolver-dns-native-macos:jar:osx-aarch_64:4.1.84.Final:runtime
[INFO] |  +- com.google.code.gson:gson:jar:2.9.1:compile
[INFO] |  +- org.yaml:snakeyaml:jar:1.30:compile
[INFO] |  \- com.alibaba:fastjson:jar:1.2.70:compile
[INFO] +- org.apache.dubbo:dubbo-dependencies-zookeeper:pom:3.0.7:compile
[INFO] |  +- org.apache.curator:curator-x-discovery:jar:4.2.0:compile
[INFO] |  |  +- org.apache.curator:curator-recipes:jar:4.2.0:compile
[INFO] |  |  |  \- org.apache.curator:curator-framework:jar:4.2.0:compile
[INFO] |  |  |     \- org.apache.curator:curator-client:jar:4.2.0:compile
[INFO] |  |  |        \- com.google.guava:guava:jar:27.0.1-jre:compile
[INFO] |  |  |           +- com.google.guava:failureaccess:jar:1.0.1:compile
[INFO] |  |  |           +- com.google.guava:listenablefuture:jar:9999.0-empty-to-avoid-conflict-with-guava:compile
[INFO] |  |  |           +- org.checkerframework:checker-qual:jar:2.5.2:compile
[INFO] |  |  |           +- com.google.errorprone:error_prone_annotations:jar:2.2.0:compile
[INFO] |  |  |           +- com.google.j2objc:j2objc-annotations:jar:1.1:compile
[INFO] |  |  |           \- org.codehaus.mojo:animal-sniffer-annotations:jar:1.17:compile
[INFO] |  |  \- com.fasterxml.jackson.core:jackson-databind:jar:2.13.4.2:compile
[INFO] |  |     +- com.fasterxml.jackson.core:jackson-annotations:jar:2.13.4:compile
[INFO] |  |     \- com.fasterxml.jackson.core:jackson-core:jar:2.13.4:compile
[INFO] |  \- org.apache.zookeeper:zookeeper:jar:3.4.14:compile
[INFO] |     +- com.github.spotbugs:spotbugs-annotations:jar:3.1.9:compile
[INFO] |     |  \- com.google.code.findbugs:jsr305:jar:3.0.2:compile
[INFO] |     +- jline:jline:jar:0.9.94:compile
[INFO] |     \- org.apache.yetus:audience-annotations:jar:0.5.0:compile
[INFO] +- org.apache.dubbo:dubbo-spring-boot-starter:jar:3.0.7:compile
[INFO] |  \- org.apache.dubbo:dubbo-spring-boot-autoconfigure:jar:3.0.7:compile
[INFO] |     \- org.apache.dubbo:dubbo-spring-boot-autoconfigure-compatible:jar:3.0.7:compile
[INFO] +- org.springframework.boot:spring-boot-starter:jar:2.7.5:compile
[INFO] |  +- org.springframework.boot:spring-boot:jar:2.7.5:compile
[INFO] |  +- org.springframework.boot:spring-boot-starter-logging:jar:2.7.5:compile
[INFO] |  |  +- ch.qos.logback:logback-classic:jar:1.2.11:compile
[INFO] |  |  |  \- ch.qos.logback:logback-core:jar:1.2.11:compile
[INFO] |  |  +- org.apache.logging.log4j:log4j-to-slf4j:jar:2.17.2:compile
[INFO] |  |  |  \- org.apache.logging.log4j:log4j-api:jar:2.17.2:compile
[INFO] |  |  \- org.slf4j:jul-to-slf4j:jar:1.7.36:compile
[INFO] |  +- jakarta.annotation:jakarta.annotation-api:jar:1.3.5:compile
[INFO] |  \- org.springframework:spring-core:jar:5.3.23:compile
[INFO] |     \- org.springframework:spring-jcl:jar:5.3.23:compile
[INFO] +- org.springframework.boot:spring-boot-autoconfigure:jar:2.7.5:compile
[INFO] +- org.slf4j:slf4j-api:jar:1.7.36:compile
[INFO] +- org.slf4j:slf4j-log4j12:jar:1.7.25:compile
[INFO] +- log4j:log4j:jar:1.2.17:compile
[INFO] \- org.projectlombok:lombok:jar:1.18.24:provided
[INFO]

找到依赖后修改

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
    <exclusions>
        <exclusion>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
        </exclusion>
    </exclusions>
</dependency>

Failed to execute goal on project xxx

执行 mvn dependency:tree 的时候错误如下

Failed to execute goal on project dubbo-demo-provider: Could not resolve dependencies for project com.qxdn.demo:dubbo-demo-provider:jar:0.0.1-SNAPSHOT: Could not find artifact com.qxdn.demo:dubbo-demo-api:jar:0.0.1-SNAPSHOT

运行

mvn clean install

完整代码

完整代码地址在 github

参考文献

dubbo 文档

Maven_dependencyManagement 多模块覆盖问题

Introduction to the Dependency Mechanism

quick start fails

Spring Boot: multiple SLF4J bindings