这种情况就是因为没有在SpringBoot中pom文件安装maven-plugin，导致出现没有主清单属性问题
1.引入插件
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
2.加载命令 mvn package
D:\MySoft\jdk1.8.0_45\bin\java.exe -Dmaven.multiModuleProjectDirectory=D:\Idea\demo "-Dmaven.home=C:\Program Files\JetBrains\IntelliJ IDEA 2020.2.4\plugins\maven\lib\maven3" "-Dclassworlds.conf=C:\Program Files\JetBrains\IntelliJ IDEA 2020.2.4\plugins\maven\lib\maven3\bin\m2.conf" "-Dmaven.ext.class.path=C:\Program Files\JetBrains\IntelliJ IDEA 2020.2.4\plugins\maven\lib\maven-event-listener.jar" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2020.2.4\lib\idea_rt.jar=52696:C:\Program Files\JetBrains\IntelliJ IDEA 2020.2.4\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\JetBrains\IntelliJ IDEA 2020.2.4\plugins\maven\lib\maven3\boot\plexus-classworlds-2.6.0.jar;C:\Program Files\JetBrains\IntelliJ IDEA 2020.2.4\plugins\maven\lib\maven3\boot\plexus-classworlds.license" org.codehaus.classworlds.Launcher -Didea.version=2020.2.4 -s D:\apache-maven-3.5.3-bin\apache-maven-3.5.3\conf\settings.xml -Dmaven.repo.local=D:\apache-maven-3.5.3-bin\maven_respository2 package
[INFO] Scanning for projects...
[INFO]
[INFO] --------------------------< com.example:demo >--------------------------
[INFO] Building demo 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:3.2.0:resources (default-resources) @ demo ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] Copying 2 resources
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ demo ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to D:\Idea\demo\target\classes
[INFO]
[INFO] --- maven-resources-plugin:3.2.0:testResources (default-testResources) @ demo ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] skip non existing resourceDirectory D:\Idea\demo\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ demo ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to D:\Idea\demo\target\test-classes
[INFO]
[INFO] --- maven-surefire-plugin:2.22.2:test (default-test) @ demo ---
[INFO]
[INFO] -------------------------------------------------------
[INFO] T E S T S
[INFO] -------------------------------------------------------
[INFO] Running com.example.demo.DemoApplicationTests
13:32:12.463 [main] DEBUG org.springframework.test.context.BootstrapUtils - Instantiating CacheAwareContextLoaderDelegate from class [org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate]
13:32:12.500 [main] DEBUG org.springframework.test.context.BootstrapUtils - Instantiating BootstrapContext using constructor [public org.springframework.test.context.support.DefaultBootstrapContext(java.lang.Class,org.springframework.test.context.CacheAwareContextLoaderDelegate)]
13:32:12.604 [main] DEBUG org.springframework.test.context.BootstrapUtils - Instantiating TestContextBootstrapper for test class [com.example.demo.DemoApplicationTests] from class [org.springframework.boot.test.context.SpringBootTestContextBootstrapper]
13:32:12.641 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Neither @ContextConfiguration nor @ContextHierarchy found for test class [com.example.demo.DemoApplicationTests], using SpringBootContextLoader
13:32:12.654 [main] DEBUG org.springframework.test.context.support.AbstractContextLoader - Did not detect default resource location for test class [com.example.demo.DemoApplicationTests]: class path resource [com/example/demo/DemoApplicationTests-context.xml] does not exist
13:32:12.655 [main] DEBUG org.springframework.test.context.support.AbstractContextLoader - Did not detect default resource location for test class [com.example.demo.DemoApplicationTests]: class path resource [com/example/demo/DemoApplicationTestsContext.groovy] does not exist
13:32:12.655 [main] INFO org.springframework.test.context.support.AbstractContextLoader - Could not detect default resource locations for test class [com.example.demo.DemoApplicationTests]: no resource found for suffixes {-context.xml, Context.groovy}.
13:32:12.657 [main] INFO org.springframework.test.context.support.AnnotationConfigContextLoaderUtils - Could not detect default configuration classes for test class [com.example.demo.DemoApplicationTests]: DemoApplicationTests does not declare any static, non-private, non-final, nested classes annotated with @Configuration.
13:32:12.793 [main] DEBUG org.springframework.test.context.support.ActiveProfilesUtils - Could not find an 'annotation declaring class' for annotation type [org.springframework.test.context.ActiveProfiles] and class [com.example.demo.DemoApplicationTests]
13:32:13.039 [main] DEBUG org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider - Identified candidate component class: file [D:\Idea\demo\target\classes\com\example\demo\DemoApplication.class]
13:32:13.043 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Found @SpringBootConfiguration com.example.demo.DemoApplication for test class com.example.demo.DemoApplicationTests
13:32:13.411 [main] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper - @TestExecutionListeners is not present for class [com.example.demo.DemoApplicationTests]: using defaults.
13:32:13.412 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Loaded default TestExecutionListener class names from location [META-INF/spring.factories]: [org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener, org.springframework.boot.test.mock.mockito.ResetMocksTestExecutionListener, org.springframework.boot.test.autoconfigure.restdocs.RestDocsTestExecutionListener, org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerResetTestExecutionListener, org.springframework.boot.test.autoconfigure.web.servlet.MockMvcPrintOnlyOnFailureTestExecutionListener, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverTestExecutionListener, org.springframework.boot.test.autoconfigure.webservices.client.MockWebServiceServerTestExecutionListener, org.springframework.test.context.web.ServletTestExecutionListener, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener, org.springframework.test.context.event.ApplicationEventsTestExecutionListener, org.springframework.test.context.support.DependencyInjectionTestExecutionListener, org.springframework.test.context.support.DirtiesContextTestExecutionListener, org.springframework.test.context.transaction.TransactionalTestExecutionListener, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener, org.springframework.test.context.event.EventPublishingTestExecutionListener]
13:32:13.455 [main] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Skipping candidate TestExecutionListener [org.springframework.test.context.transaction.TransactionalTestExecutionListener] due to a missing dependency. Specify custom listener classes or make the default listener classes and their required dependencies available. Offending class: [org/springframework/transaction/interceptor/TransactionAttributeSource]
13:32:13.457 [main] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Skipping candidate TestExecutionListener [org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener] due to a missing dependency. Specify custom listener classes or make the default listener classes and their required dependencies available. Offending class: [org/springframework/transaction/interceptor/TransactionAttribute]
13:32:13.458 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Using TestExecutionListeners: [org.springframework.test.context.web.ServletTestExecutionListener@e4deb0, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener@9175d8, org.springframework.test.context.event.ApplicationEventsTestExecutionListener@10b7e3c, org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener@1bb5034, org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener@1741d6d, org.springframework.test.context.support.DirtiesContextTestExecutionListener@ae8e6e, org.springframework.test.context.event.EventPublishingTestExecutionListener@f2ef19, org.springframework.boot.test.mock.mockito.ResetMocksTestExecutionListener@10734c3, org.springframework.boot.test.autoconfigure.restdocs.RestDocsTestExecutionListener@f3d63b, org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerResetTestExecutionListener@74f035, org.springframework.boot.test.autoconfigure.web.servlet.MockMvcPrintOnlyOnFailureTestExecutionListener@1e153c5, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverTestExecutionListener@13ed316, org.springframework.boot.test.autoconfigure.webservices.client.MockWebServiceServerTestExecutionListener@1ce9dc4]
13:32:13.470 [main] DEBUG org.springframework.test.context.support.AbstractDirtiesContextTestExecutionListener - Before test class: context [DefaultTestContext@a3b418 testClass = DemoApplicationTests, testInstance = [null], testMethod = [null], testException = [null], mergedContextConfiguration = [WebMergedContextConfiguration@cbafc2 testClass = DemoApplicationTests, locations = '{}', classes = '{class com.example.demo.DemoApplication}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{org.springframework.boot.test.context.SpringBootTestContextBootstrapper=true}', contextCustomizers = set[org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizer@47e447, org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory$DuplicateJsonObjectContextCustomizer@1ef1869, org.springframework.boot.test.mock.mockito.MockitoContextCustomizer@0, org.springframework.boot.test.web.client.TestRestTemplateContextCustomizer@fd44cb, org.springframework.boot.test.autoconfigure.actuate.metrics.MetricsExportContextCustomizerFactory$DisableMetricExportContextCustomizer@18d318c, org.springframework.boot.test.autoconfigure.properties.PropertyMappingContextCustomizer@0, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverContextCustomizerFactory$Customizer@158da8e, org.springframework.boot.test.context.SpringBootTestArgs@1, org.springframework.boot.test.context.SpringBootTestWebEnvironment@fc185], resourceBasePath = 'src/main/webapp', contextLoader = 'org.springframework.boot.test.context.SpringBootContextLoader', parent = [null]], attributes = map['org.springframework.test.context.web.ServletTestExecutionListener.activateListener' -> true]], class annotated with @DirtiesContext [false] with mode [null].
13:32:13.562 [main] DEBUG org.springframework.test.context.support.TestPropertySourceUtils - Adding inlined properties to environment: {spring.jmx.enabled=false, org.springframework.boot.test.context.SpringBootTestContextBootstrapper=true}
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.4.4)
2021-04-15 13:32:14.313 INFO 11780 --- [ main] com.example.demo.DemoApplicationTests : Starting DemoApplicationTests using Java 1.8.0_45 on DESKTOP-246K8S5 with PID 11780 (started by 10511 in D:\Idea\demo)
2021-04-15 13:32:14.320 INFO 11780 --- [ main] com.example.demo.DemoApplicationTests : No active profile set, falling back to default profiles: default
2021-04-15 13:32:17.050 INFO 11780 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2021-04-15 13:32:17.873 INFO 11780 --- [ main] com.example.demo.DemoApplicationTests : Started DemoApplicationTests in 4.294 seconds (JVM running for 6.714)
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 6.079 s - in com.example.demo.DemoApplicationTests
2021-04-15 13:32:18.464 INFO 11780 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'
[INFO]
[INFO] Results:
[INFO]
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO]
[INFO]
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ demo ---
[INFO] Building jar: D:\Idea\demo\target\demo-0.0.1-SNAPSHOT.jar
[INFO]
[INFO] --- spring-boot-maven-plugin:2.4.4:repackage (repackage) @ demo ---
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 17.444 s
[INFO] Finished at: 2021-04-15T13:32:22+08:00
[INFO] ------------------------------------------------------------------------
重新打包运行文件，完美解决
2.如果是MAVEN项目
<build>
<finalName>{file_name}</finalName><!-- 导出jar包的名字 -->
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.2.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<transformers>
<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>{Mainclass}</mainClass>
<!-- 主类的位置，修改成主配置类即可，主类配置应为： -->
<!-- <mainClass>fatcats.top.App</mainClass> -->
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
