所以我已经尝试了这些：

< li >在pom.xml中添加插件 < li >删除. m2文件夹以在作为Maven版本运行时清理包... < li >运行mvn clean(在eclipse IDE中的项目文件夹上) < li >关闭并再次运行eclipse。

事情是这样的:当我在eclipse上将主类作为Java应用程序运行时，eclipse控制台显示应用程序以spring logo启动。但是当我让Maven构建或提取项目时。jar文件并尝试做java -jar时，出现一个异常:

线程“main”Java . lang . noclassdeffounderror:org/spring framework/boot/spring application at br . com . bancodigimais . keypaypagamentos . portalpos . portalposapplication . main(portalposapplication . Java:34)中的异常由以下原因引起:Java . lang . classnotfoundexception:org . spring framework . boot . spring application at Java . base

为什么会发生这种情况？我的意思是。。。有可能使这个项目将jar构建为可执行文件吗？当您使用java -jar命令并看到Spring徽标启动应用程序等时...

pom.xml文件：

<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>
    <groupId>Portal-POS</groupId>
    <artifactId>Portal-POS</artifactId>
    <packaging>jar</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <build>
        <sourceDirectory>src</sourceDirectory>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>            
                </configuration>
            </plugin>
     <plugin> 

                <!-- Building an executable jar -->

                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.1.0</version>
                <configuration>
                  <archive>
                    <manifest>

                    <!-- give full qualified name of your main class-->
                      <mainClass>br.com.bancodigimais.keypaypagamentos.portalpos.PortalPosApplication</mainClass>

                    </manifest>
                  </archive>
                </configuration>
    </plugin>
 
            
        </plugins>
    </build>

    <dependencies>

        <dependency>
            <groupId>com.liferay</groupId>
            <artifactId>com.liferay.gradle.plugins.jasper.jspc</artifactId>
            <version>2.0.5</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-log4j2</artifactId>
            <version>2.1.3.RELEASE</version>
            <exclusions>
                <exclusion>
                    <groupId>org.apache.logging.log4j</groupId>
                    <artifactId>log4j-slf4j-impl</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot</artifactId>
            <version>2.1.7.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.7</version>
        </dependency>

        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>42.2.5</version>
        </dependency>

        <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
            <version>2.10.1</version>
        </dependency>

        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.5</version>
        </dependency>


        <dependency>
            <groupId>com.auth0</groupId>
            <artifactId>java-jwt</artifactId>
            <version>3.4.0</version>
        </dependency>

        <dependency>
            <groupId>net.sf.supercsv</groupId>
            <artifactId>super-csv-java8</artifactId>
            <version>2.4.0</version>
        </dependency>

        <dependency>
            <groupId>net.sf.jasperreports</groupId>
            <artifactId>jasperreports</artifactId>
            <version>6.7.0</version>
        </dependency>

        <dependency>
            <groupId>org.codehaus.groovy</groupId>
            <artifactId>groovy-all</artifactId>
            <version>2.3.6</version>
        </dependency>

        <dependency>
            <groupId>com.lowagie</groupId>
            <artifactId>itext</artifactId>
            <version>2.1.7</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>4.0.1</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>4.0.1</version>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-email</artifactId>
            <version>1.5</version>
        </dependency>

        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.9.2</version>
        </dependency>

        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.9.2</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.10</version>
            <scope>provided</scope>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.1.3.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
            <version>2.1.3.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.9</version>
        </dependency>

        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-core-asl</artifactId>
            <version>1.9.13</version>
        </dependency>

        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-mapper-asl</artifactId>
            <version>1.9.13</version>
        </dependency>

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
            <version>4.5.10</version>
        </dependency>

        <dependency>
            <groupId>javax.ws.rs</groupId>
            <artifactId>javax.ws.rs-api</artifactId>
            <version>2.1.1</version>
        </dependency>

        <dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-core</artifactId>
            <version>3.3.6</version>
        </dependency>

        <dependency>
            <groupId>commons-httpclient</groupId>
            <artifactId>commons-httpclient</artifactId>
            <version>3.1</version>
        </dependency>
    </dependencies>
</project>