Maven项目中ClassNotFoundException问题

Question

我被分配去完成一个项目，作为我求职申请的一部分。公司派我来安装的要求如下：

• OpenJDK 1.8
• Maven 3.x
• Git 2.x
• MySQL 5.x.

我试图从服务器端（Java）运行应用程序，它抛出了这个异常（可能是依赖关系问题，但我找不到）：

2020-08-30 07:34:56.850错误org.springframework.boot.springapplication:858-应用程序运行失败java.lang.nclassdeffounder错误：org.springframework.boot/bind/relaxeddatabinder在org.springframework.boot.autocigurationimportselector.getexclusions（enableautocigurationimportselector.java:179)在org.springframework.boot.autocigurationautocigurationselector.java:172)SelectorRoupingHandler.ProcessGroupImports（ConfigurationClassParser.java:804)位于org.SpringFramework.Context.Annotation.configurationClassParser.java:774)位于org.SpringFramework.Context.Annotation.configurationClassParser.parse（ConfigurationClassParser.java:185)位于org.SpringFramework.Context.Annotation.configurationClassPostProcessor.ProcessConfigBeanDefinitions（keBeanFactoryPostProcessors（AbstractApplicationContext.java:705)位于org.springframework.context.support.AbstractApplicationContext.Refresh（AbstractApplicationContext.java:531)位于org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.Refresh（ServletWebServerApplicationContext.java:142）位于org.springframework.boot.springApplication.Refresh（lect.delegatingMethodAccessorImpl.Invoke(DelegatingMethodAccessorImpl.java:43)，在java.base/java.lang.Reflect.Method.Invoke(method.java:566)，在org.springframework.boot.devtools.restartlauncher.run(restartlauncher.java:49)原因：java.lang.classnotfoundexception：org.springframework.boot.bind.relaxeddatabinder在

**Pom.xml(general in project)**
<?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>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.4.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<groupId>gr.publicsoft.springbootcrud</groupId>
<artifactId>spring-boot-crud</artifactId>
<packaging>pom</packaging>
<version>1.0-SNAPSHOT</version>

<properties>
    <java.version>1.8</java.version>
</properties>

<modules>
    <module>springbootcrud-domain</module>
    <module>springbootcrud-service</module>
    <module>springbootcrud-webapp</module>
</modules>

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
    </plugins>
</build>

</project>

**Pom.xml(inside app folder)**
<?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>spring-boot-crud</artifactId>
    <groupId>gr.publicsoft.springbootcrud</groupId>
    <version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>

<artifactId>springbootcrud-webapp</artifactId>



<properties>
    <java.version>1.8</java.version>
    <finalName>${project.artifactId}-${project.version}</finalName>
</properties>

<profiles>
    <profile>
        <id>dev</id>
        <activation>
            <activeByDefault>true</activeByDefault>
        </activation>
    </profile>
</profiles>

<dependencies>

    <dependency>
        <groupId>gr.publicsoft.springbootcrud</groupId>
        <artifactId>springbootcrud-service</artifactId>
        <version>${project.parent.version}</version>
    </dependency>

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

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.liquibase</groupId>
        <artifactId>liquibase-core</artifactId>
    </dependency>
    <dependency>
        <groupId>eu.bitwalker</groupId>
        <artifactId>UserAgentUtils</artifactId>
        <version>1.21</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-autoconfigure</artifactId>
        <version>1.4.1.RELEASE</version>
    </dependency>
</dependencies>

<build>
    <finalName>${finalName}</finalName>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
                <executable>true</executable>
            </configuration>
        </plugin>
    </plugins>
</build>

</project>

Answer 1

实际上，spring-boot-starter-parent包含spring-boot-autocigure，请参阅https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-parent/2.3.3.release以了解托管依赖关系。

如果您特别指定了这个版本（即有两个不同的版本），则可能会发生错误。