将我自己的框架添加为依赖项，并在启动项目时获取错误

Question

我在我的核心框架中使用了Java-17和Spring2.6.7，并在另一个Spring项目中添加了它作为依赖项，但是在启动依赖项目时会出现以下错误，即使我试图从子项目中排除重复的依赖项。

    <?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.7</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.my.core</groupId>
    <artifactId>my-core</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>my-core</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>17</java.version>
        <spring-cloud.version>2021.0.2</spring-cloud.version>
    </properties>
    <dependencies>
        <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.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web-services</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-sleuth</artifactId>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-zipkin</artifactId>
                <version>${spring-cloud.version}</version>
                <scope>runtime</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

下面是子项目

4.0.0

<groupId>com.example</groupId>
<artifactId>microservice3</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>microservice3</name>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.6.3</version>
    <relativePath /> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <maven.compiler.source>17</maven.compiler.source>
    <maven.compiler.target>17</maven.compiler.target>
</properties>

<dependencies>
    <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.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web-services</artifactId>
    </dependency>
    <dependency>
        <groupId>com.my.core</groupId>
        <artifactId>my-core</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <type>jar</type>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web-services</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

当启动子项目时出现以下错误

    org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'braveHttpServerHandler' defined in class path resource [org/springframework/cloud/sleuth/autoconfig/brave/instrument/web/BraveHttpBridgeConfiguration.class]: Unsatisfied dependency expressed through method 'braveHttpServerHandler' parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'httpTracing' defined in class path resource [org/springframework/cloud/sleuth/autoconfig/brave/instrument/web/BraveHttpConfiguration.class]: Unsatisfied dependency expressed through method 'httpTracing' parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'tracing' defined in class path resource [org/springframework/cloud/sleuth/autoconfig/brave/BraveAutoConfiguration.class]: Unsatisfied dependency expressed through method 'tracing' parameter 3; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'microservice3Controller': Unsatisfied dependency expressed through field 'restTemplate'; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'microservice3Controller': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.15.jar:5.3.15]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:541) ~[spring-beans-5.3.15.jar:5.3.15]
    ..............
    .
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1292) ~[spring-boot-2.6.3.jar:2.6.3]
    at com.javainuse.Microservice3Application.main(Microservice3Application.java:22) ~[classes/:na]
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'httpTracing' defined in class path resource [org/springframework/cloud/sleuth/autoconfig/brave/instrument/web/BraveHttpConfiguration.class]: Unsatisfied dependency expressed through method 'httpTracing' parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'tracing' defined in class path resource [org/springframework/cloud/sleuth/autoconfig/brave/BraveAutoConfiguration.class]: Unsatisfied dependency expressed through method 'tracing' parameter 3; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'microservice3Controller': Unsatisfied dependency expressed through field 'restTemplate'; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'microservice3Controller': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.15.jar:5.3.15]
    
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'tracing' defined in class path resource [org/springframework/cloud/sleuth/autoconfig/brave/BraveAutoConfiguration.class]: Unsatisfied dependency expressed through method 'tracing' parameter 3; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'microservice3Controller': Unsatisfied dependency expressed through field 'restTemplate'; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'microservice3Controller': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.15.jar:5.3.15]
    
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'microservice3Controller': Unsatisfied dependency expressed through field 'restTemplate'; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'microservice3Controller': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:659) ~[spring-beans-5.3.15.jar:5.3.15]
    
Caused by: org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'microservice3Controller': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.beforeSingletonCreation(DefaultSingletonBeanRegistry.java:355) ~[spring-beans-5.3.15.jar:5.3.15]

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-06-02 00:47:47.270 ERROR [microservice3,,] 16932 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:163) ~[spring-boot-2.6.3.jar:2.6.3]
    ............
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
    at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatW

ebServer.java:142) ~[spring-boot-2.6.3.jar:2.6.3]
    ..............
Caused by: java.lang.IllegalStateException: StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[] failed to start
    at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.rethrowDeferredStartupExceptions(TomcatWebServer.java:187) ~[spring-boot-2.6.3.jar:2.6.3]
    at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:126) ~[spring-boot-2.6.3.jar:2.6.3]
    ... 13 common frames omitted


Process finished with exit code 1

Answer 1

在自动配置侦察/Zipkin跟踪时，microservice3Controller和restTemplate之间存在一些循环依赖关系。

在Spring中有多种解决循环依赖的方法，例如@Lazy bean自动装配，使用setter注入等。有关更多细节，请查看https://www.baeldung.com/circular-dependencies-in-spring。