创建名为'entityManagerFactory' spring boot application的bean时出错

当我编译我的 Spring 季启动项目时，得到以下错误 .

org.springframework.beans.factory.BeanCreationException：在类路径资源[com / biganalytics / project / configuration / JpaConfiguration.class]中定义的名称为'entityManagerFactory'的bean创建错误：通过工厂方法的Bean实例化失败;嵌套异常是org.springframework.beans.BeanInstantiationException：无法实例化[org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean]：工厂方法'entityManagerFactory'抛出异常;嵌套异常是java.lang.IllegalStateException：在org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod（ConstructorResolver.java:599）〜[spring-beans-4.3]中找不到所需的密钥[datasource.sampleapp.hibernate.dialect] .6.RELEASE.jar：4.3.6.RELEASE]在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod（AbstractAutowireCapableBeanFactory.java:1173）〜[spring-beans-4.3.6.RELEASE.jar：4.3 . 6.RELEASE] org.springframework上的org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067)~ [spring-beans-4.3.6.RELEASE.jar：4.3.6.RELEASE] . bean.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean（AbstractAutowireCapableBeanFactory.java:513）〜[spring-beans-4.3.6.RELEASE.jar：4.3.6.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean （AbstractAutowireCapableBeanFactory.j ava：483）〜[spring-beans-4.3.6.RELEASE.jar：4.3.6.RELEASE] org.springframework.beans.factory.support.AbstractBeanFactory $ 1.getObject（AbstractBeanFactory.java:306）〜[spring- bean-4.3.6.RELEASE.jar：4.3.6.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton（DefaultSingletonBeanRegistry.java:230）〜[spring-beans-4.3.6.RELEASE.jar ：4.3.6.RELEASE] org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean（AbstractBeanFactory.java:302）〜[spring-beans-4.3.6.RELEASE.jar：4.3.6.RELEASE] at org org.springframework.context.support.AbstractApplicationContext中的.springframework.beans.factory.support.AbstractBeanFactory.getBean（AbstractBeanFactory.java:197)~ [spring-beans-4.3.6.RELEASE.jar：4.3.6.RELEASE] . orB.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization（AbstractApplicationContext.java:856）〜[spring]中的getBean（AbstractApplicationContext.java:1081）〜[spring-context-4.3.6.RELEASE.jar：4.3.6.RELEASE] -CONT在org.springframework.context.support.AbstractApplicationContext.refresh（AbstractApplicationContext.java:542）〜[spring-context-4.3.6.RELEASE.jar：4.3中的ext-4.3.6.RELEASE.jar：4.3.6.RELEASE] .6.RELEASE] org.springframework上的org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh（EmbeddedWebApplicationContext.java:122)~ [spring-boot-1.5.1.RELEASE.jar：1.5.1.RELEASE] .boot.SpringApplication.refresh（SpringApplication.java:737）[spring-boot-1.5.1.RELEASE.jar：1.5.1.RELEASE]在org.springframework.boot.SpringApplication.refreshContext（SpringApplication.java:370）[ spring-boot-1.5.1.RELEASE.jar：1.5.1.RELEASE] at org.springframework.boot.SpringApplication.run（SpringApplication.java:314）[spring-boot-1.5.1.RELEASE.jar：1.5 . 1.RELEASE] org.springframework.boot.SpringApplication.run（SpringApplication.java:1162）[spring-boot-1.5.1.RELEASE.jar：1.5.1.RELEASE] org.springframework.boot.SpringApplication.run （SpringApplication.java:1151）[spring-boot-1.5.1.RELEASE.jar：1.5.1.RELE ASE] at com.biganalytics.project.WebApplication.main（WebApplication.java:19）[classes /：na]引起：org.springframework.beans.BeanInstantiationException：无法实例化[org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean] ：工厂方法'entityManagerFactory'抛出异常;嵌套异常是java.lang.IllegalStateException：在org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate（SimpleInstantiationStrategy.java:189）〜[spring-beans-4.3]中找不到所需的密钥[datasource.sampleapp.hibernate.dialect] .6.RELEASE.jar：4.3.6.RELEASE]在org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod（ConstructorResolver.java:588）〜[spring-beans-4.3.6.RELEASE.jar：4.3 . 6.RELEASE] ...省略了18个常见帧引起：java.lang.IllegalStateException：在org.springframework.core.env.AbstractPropertyResolver.getRequiredProperty（AbstractPropertyResolver.java：）中找不到所需的键[datasource.sampleapp.hibernate.dialect] 183）〜[spring-core-4.3.6.RELEASE.jar：4.3.6.RELEASE] org.springframework.core.env.AbstractEnvironment.getRequiredProperty（AbstractEnvironment.java:556)~ [spring-core-4.3.6 .RELEASE.jar：4.3.6.RELEASE] at com.biganalytics.project.configuration.JpaConfiguration.jpaProperties（JpaConfiguration.java ：99）〜[classes /：na] atcom.biganalytics.project.configuration.JpaConfiguration.entityManagerFactory（JpaConfiguration.java:81）〜[classes /：na] at com.biganalytics.project.configuration.JpaConfiguration $$ EnhancerBySpringCGLIB $$ 5f74f23d.CGLIB $ entityManagerFactory $ 1（）〜[ classes /：na] at com.biganalytics.project.configuration.JpaConfiguration $$ EnhancerBySpringCGLIB $$ 5f74f23d $$ FastClassBySpringCGLIB $$ 6189aa41.invoke（）〜[classes /：na] at org.springframework.cglib.proxy.MethodProxy.invokeSuper （MethodProxy.java:228）〜[spring-core-4.3.6.RELEASE.jar：4.3.6.RELEASE] org.springframework.context.annotation.ConfigurationClassEnhancer $ BeanMethodInterceptor.intercept（ConfigurationClassEnhancer.java:356)~ [ spring-context-4.3.6.RELEASE.jar：4.3.6.RELEASE] at com.biganalytics.project.configuration.JpaConfiguration $$ EnhancerBySpringCGLIB $$ 5f74f23d.entityManagerFactory（）〜[classes /：na] at sun.reflect . NativeMethodAccessorImpl.invoke0（Native Method）〜[na：1.8.0_112] at sun.reflect.NativeMethodAccessorImpl.invoke（Unknown Source）〜[na：1 .8.0_112]在org.springframework的java.lang.reflect.Method.invoke（未知来源）〜[na：1.8.0_112]的sun.reflect.DelegatingMethodAccessorImpl.invoke（未知来源）〜[na：1.8.0_112] .beans.factory.support.SimpleInstantiationStrategy.instantiate（SimpleInstantiationStrategy.java:162)~ [spring-beans-4.3.6.RELEASE.jar：4.3.6.RELEASE] ...省略了19个常用帧

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