菜鸟问题在这里。正如标题所暗示的那样，我正在尝试使用 Spring 注释在休眠中创建数据库配置。不确定我是否以最聪明的方式做到这一点，可能不是，但我已经坚持了一段时间。提前谢谢。
主类：
@EnableAutoConfiguration
@ComponentScan
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class);
}
}
数据库配置类：
@Configuration
public class DataConfig {
private String DB_DRIVER = "com.mysql.jdbc.Driver";
private String DB_USERNAME = "springstudent";
private String DB_PASSWORD = "springstudent";
private String DB_URL = "jdbc:mysql://localhost:3306/web_customer_tracker";
private String HIBERNATE_DIALECT = "org.hibernate.dialect.MySQL5Dialect";
private String HIBERNATE_SHOW_SQL = "true";
private String HIBERNATE_HBM2DDL_AUTO ="create-drop";
private String ENTITYMANAGER_PACKAGES_TO_SCAN = "com.luv2code.springtutorial.entity";
@Bean
public LocalSessionFactoryBean sessionFactory(){
LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
sessionFactory.setDataSource(dataSource());
sessionFactory.setPackagesToScan(ENTITYMANAGER_PACKAGES_TO_SCAN);
Properties hibernateProperties = new Properties();
hibernateProperties.put("hibernate.dialect", HIBERNATE_DIALECT);
hibernateProperties.put("hibernate.show_sql", HIBERNATE_SHOW_SQL);
sessionFactory.setHibernateProperties(hibernateProperties);
return sessionFactory;
}
@Bean
public DriverManagerDataSource dataSource(){
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClass(DB_DRIVER);
dataSource.setUser(DB_URL);
dataSource.setUser(DB_USERNAME);
dataSource.setPassword(DB_PASSWORD);
return dataSource;
}
}
道：
public interface CustomerDao {
List<Customer> getCustomers();
}
DAOImpl：
@Repository
public class CustomerDaoImpl implements CustomerDao{
@Autowired
private SessionFactory sessionFactory;
@Override
public List<Customer> getCustomers() {
Session session = sessionFactory.getCurrentSession();
session.beginTransaction();
Query<Customer> theQuery = session.createQuery("FROM CUSTOMER", Customer.class);
List<Customer> customers = theQuery.getResultList();
session.getTransaction().commit();
return customers;
}
}
堆栈跟踪：
/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/bin/java -Didea.launcher.port=7533 "-Didea.launcher.bin.path=/Applications/IntelliJ IDEA CE.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath "/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/lib/tools.jar:/Users/ronald/IdeaProjects/springtutorial/target/classes:/Users/ronald/.m2/repository/org/springframework/boot/spring-boot-starter-thymeleaf/1.5.1.RELEASE/spring-boot-starter-thymeleaf-1.5.1.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/boot/spring-boot-starter/1.5.1.RELEASE/spring-boot-starter-1.5.1.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/boot/spring-boot/1.5.1.RELEASE/spring-boot-1.5.1.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/boot/spring-boot-autoconfigure/1.5.1.RELEASE/spring-boot-autoconfigure-1.5.1.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/boot/spring-boot-starter-logging/1.5.1.RELEASE/spring-boot-starter-logging-1.5.1.RELEASE.jar:/Users/ronald/.m2/repository/ch/qos/logback/logback-classic/1.1.9/logback-classic-1.1.9.jar:/Users/ronald/.m2/repository/ch/qos/logback/logback-core/1.1.9/logback-core-1.1.9.jar:/Users/ronald/.m2/repository/org/slf4j/jul-to-slf4j/1.7.22/jul-to-slf4j-1.7.22.jar:/Users/ronald/.m2/repository/org/slf4j/log4j-over-slf4j/1.7.22/log4j-over-slf4j-1.7.22.jar:/Users/ronald/.m2/repository/org/yaml/snakeyaml/1.17/snakeyaml-1.17.jar:/Users/ronald/.m2/repository/org/thymeleaf/thymeleaf-spring4/2.1.5.RELEASE/thymeleaf-spring4-2.1.5.RELEASE.jar:/Users/ronald/.m2/repository/nz/net/ultraq/thymeleaf/thymeleaf-layout-dialect/1.4.0/thymeleaf-layout-dialect-1.4.0.jar:/Users/ronald/.m2/repository/org/codehaus/groovy/groovy/2.4.7/groovy-2.4.7.jar:/Users/ronald/.m2/repository/org/springframework/boot/spring-boot-starter-web/1.5.1.RELEASE/spring-boot-starter-web-1.5.1.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/boot/spring-boot-starter-tomcat/1.5.1.RELEASE/spring-boot-starter-tomcat-1.5.1.RELEASE.jar:/Users/ronald/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/8.5.11/tomcat-embed-core-8.5.11.jar:/Users/ronald/.m2/repository/org/apache/tomcat/embed/tomcat-embed-el/8.5.11/tomcat-embed-el-8.5.11.jar:/Users/ronald/.m2/repository/org/apache/tomcat/embed/tomcat-embed-websocket/8.5.11/tomcat-embed-websocket-8.5.11.jar:/Users/ronald/.m2/repository/org/hibernate/hibernate-validator/5.3.4.Final/hibernate-validator-5.3.4.Final.jar:/Users/ronald/.m2/repository/javax/validation/validation-api/1.1.0.Final/validation-api-1.1.0.Final.jar:/Users/ronald/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.8.6/jackson-databind-2.8.6.jar:/Users/ronald/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.8.0/jackson-annotations-2.8.0.jar:/Users/ronald/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.8.6/jackson-core-2.8.6.jar:/Users/ronald/.m2/repository/org/springframework/spring-web/4.3.6.RELEASE/spring-web-4.3.6.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/spring-aop/4.3.6.RELEASE/spring-aop-4.3.6.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/spring-context/4.3.6.RELEASE/spring-context-4.3.6.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/spring-webmvc/4.3.6.RELEASE/spring-webmvc-4.3.6.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/spring-expression/4.3.6.RELEASE/spring-expression-4.3.6.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/spring-core/4.3.6.RELEASE/spring-core-4.3.6.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/spring-orm/4.3.7.RELEASE/spring-orm-4.3.7.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/spring-beans/4.3.6.RELEASE/spring-beans-4.3.6.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/spring-jdbc/4.3.6.RELEASE/spring-jdbc-4.3.6.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/spring-tx/4.3.6.RELEASE/spring-tx-4.3.6.RELEASE.jar:/Users/ronald/.m2/repository/org/hibernate/hibernate-core/5.2.9.Final/hibernate-core-5.2.9.Final.jar:/Users/ronald/.m2/repository/org/jboss/logging/jboss-logging/3.3.0.Final/jboss-logging-3.3.0.Final.jar:/Users/ronald/.m2/repository/org/hibernate/javax/persistence/hibernate-jpa-2.1-api/1.0.0.Final/hibernate-jpa-2.1-api-1.0.0.Final.jar:/Users/ronald/.m2/repository/org/javassist/javassist/3.21.0-GA/javassist-3.21.0-GA.jar:/Users/ronald/.m2/repository/antlr/antlr/2.7.7/antlr-2.7.7.jar:/Users/ronald/.m2/repository/org/jboss/spec/javax/transaction/jboss-transaction-api_1.2_spec/1.0.1.Final/jboss-transaction-api_1.2_spec-1.0.1.Final.jar:/Users/ronald/.m2/repository/org/jboss/jandex/2.0.3.Final/jandex-2.0.3.Final.jar:/Users/ronald/.m2/repository/com/fasterxml/classmate/1.3.3/classmate-1.3.3.jar:/Users/ronald/.m2/repository/dom4j/dom4j/1.6.1/dom4j-1.6.1.jar:/Users/ronald/.m2/repository/org/hibernate/common/hibernate-commons-annotations/5.0.1.Final/hibernate-commons-annotations-5.0.1.Final.jar:/Users/ronald/.m2/repository/mysql/mysql-connector-java/5.1.39/mysql-connector-java-5.1.39.jar:/Users/ronald/.m2/repository/c3p0/c3p0/0.9.1.2/c3p0-0.9.1.2.jar:/Users/ronald/.m2/repository/commons-logging/commons-logging/1.1.1/commons-logging-1.1.1.jar:/Users/ronald/.m2/repository/org/springframework/boot/spring-boot-starter-data-jpa/1.5.1.RELEASE/spring-boot-starter-data-jpa-1.5.1.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/boot/spring-boot-starter-aop/1.5.1.RELEASE/spring-boot-starter-aop-1.5.1.RELEASE.jar:/Users/ronald/.m2/repository/org/aspectj/aspectjweaver/1.8.9/aspectjweaver-1.8.9.jar:/Users/ronald/.m2/repository/org/springframework/boot/spring-boot-starter-jdbc/1.5.1.RELEASE/spring-boot-starter-jdbc-1.5.1.RELEASE.jar:/Users/ronald/.m2/repository/org/apache/tomcat/tomcat-jdbc/8.5.11/tomcat-jdbc-8.5.11.jar:/Users/ronald/.m2/repository/org/apache/tomcat/tomcat-juli/8.5.11/tomcat-juli-8.5.11.jar:/Users/ronald/.m2/repository/org/hibernate/hibernate-entitymanager/5.0.11.Final/hibernate-entitymanager-5.0.11.Final.jar:/Users/ronald/.m2/repository/javax/transaction/javax.transaction-api/1.2/javax.transaction-api-1.2.jar:/Users/ronald/.m2/repository/org/springframework/data/spring-data-jpa/1.11.0.RELEASE/spring-data-jpa-1.11.0.RELEASE.jar:/Users/ronald/.m2/repository/org/springframework/data/spring-data-commons/1.13.0.RELEASE/spring-data-commons-1.13.0.RELEASE.jar:/Users/ronald/.m2/repository/org/slf4j/jcl-over-slf4j/1.7.22/jcl-over-slf4j-1.7.22.jar:/Users/ronald/.m2/repository/org/springframework/spring-aspects/4.3.6.RELEASE/spring-aspects-4.3.6.RELEASE.jar:/Users/ronald/.m2/repository/org/thymeleaf/thymeleaf-spring3/3.0.3.RELEASE/thymeleaf-spring3-3.0.3.RELEASE.jar:/Users/ronald/.m2/repository/org/thymeleaf/thymeleaf/2.1.5.RELEASE/thymeleaf-2.1.5.RELEASE.jar:/Users/ronald/.m2/repository/org/unbescape/unbescape/1.1.0.RELEASE/unbescape-1.1.0.RELEASE.jar:/Users/ronald/.m2/repository/org/slf4j/slf4j-api/1.7.22/slf4j-api-1.7.22.jar:/Applications/IntelliJ IDEA CE.app/Contents/lib/idea_rt.jar" com.intellij.rt.execution.application.AppMain com.luv2code.springtutorial.Application
. ____ _ __ _ _
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( ( )___ | '_ | '_| | '_ / _` |
\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |___, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.1.RELEASE)
2017-04-09 14:00:17.636 INFO 2361 --- [ main] com.luv2code.springtutorial.Application : Starting Application on Ronalds-MacBook-Pro.local with PID 2361 (/Users/ronald/IdeaProjects/springtutorial/target/classes started by ronald in /Users/ronald/IdeaProjects/springtutorial)
2017-04-09 14:00:17.640 INFO 2361 --- [ main] com.luv2code.springtutorial.Application : No active profile set, falling back to default profiles: default
2017-04-09 14:00:18.157 INFO 2361 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@279ad2e3: startup date [Sun Apr 09 14:00:18 EDT 2017]; root of context hierarchy
2017-04-09 14:00:20.863 INFO 2361 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration' of type [class org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2017-04-09 14:00:21.039 INFO 2361 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'validator' of type [class org.springframework.validation.beanvalidation.LocalValidatorFactoryBean] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2017-04-09 14:00:21.209 INFO 2361 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration' of type [class org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$8550c927] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2017-04-09 14:00:22.109 INFO 2361 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2017-04-09 14:00:22.137 INFO 2361 --- [ main] o.apache.catalina.core.StandardService : Starting service Tomcat
2017-04-09 14:00:22.139 INFO 2361 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.11
2017-04-09 14:00:22.322 INFO 2361 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2017-04-09 14:00:22.323 INFO 2361 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 4172 ms
2017-04-09 14:00:22.602 INFO 2361 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
2017-04-09 14:00:22.611 INFO 2361 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2017-04-09 14:00:22.611 INFO 2361 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2017-04-09 14:00:22.611 INFO 2361 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2017-04-09 14:00:22.612 INFO 2361 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2017-04-09 14:00:22.759 INFO 2361 --- [ main] com.mchange.v2.log.MLog : MLog clients using log4j logging.
2017-04-09 14:00:28.056 INFO 2361 --- [ main] org.hibernate.Version : HHH000412: Hibernate Core {5.2.9.Final}
2017-04-09 14:00:28.060 INFO 2361 --- [ main] org.hibernate.cfg.Environment : HHH000206: hibernate.properties not found
2017-04-09 14:00:28.131 INFO 2361 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {5.0.1.Final}
2017-04-09 14:00:28.372 WARN 2361 --- [ main] o.h.e.j.e.i.JdbcEnvironmentInitiator : HHH000342: Could not obtain connection to query metadata : null
2017-04-09 14:00:28.403 INFO 2361 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.MySQL5Dialect
2017-04-09 14:00:28.446 INFO 2361 --- [ main] o.h.e.j.e.i.LobCreatorBuilderImpl : HHH000422: Disabling contextual LOB creation as connection was null
2017-04-09 14:00:30.032 INFO 2361 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@279ad2e3: startup date [Sun Apr 09 14:00:18 EDT 2017]; root of context hierarchy
2017-04-09 14:00:30.202 INFO 2361 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/customer/list]}" onto public java.lang.String com.luv2code.springtutorial.controller.CustomerController.listCustomers(org.springframework.ui.Model)
2017-04-09 14:00:30.207 INFO 2361 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2017-04-09 14:00:30.208 INFO 2361 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2017-04-09 14:00:30.283 INFO 2361 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-04-09 14:00:30.284 INFO 2361 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-04-09 14:00:30.351 INFO 2361 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-04-09 14:00:31.113 WARN 2361 --- [ main] ationConfigEmbeddedWebApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaVendorAdapter' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.jpa.JpaVendorAdapter]: Factory method 'jpaVendorAdapter' threw exception; nested exception is java.lang.NullPointerException
2017-04-09 14:00:31.114 INFO 2361 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
2017-04-09 14:00:31.129 INFO 2361 --- [ main] utoConfigurationReportLoggingInitializer :
Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2017-04-09 14:00:31.141 ERROR 2361 --- [ main] o.s.boot.SpringApplication : Application startup failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaVendorAdapter' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.jpa.JpaVendorAdapter]: Factory method 'jpaVendorAdapter' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:599) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1173) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.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.java:483) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-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]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866) ~[spring-context-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:737) [spring-boot-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at 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]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162) [spring-boot-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151) [spring-boot-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at com.luv2code.springtutorial.Application.main(Application.java:13) [classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147) [idea_rt.jar:na]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.jpa.JpaVendorAdapter]: Factory method 'jpaVendorAdapter' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
... 23 common frames omitted
Caused by: java.lang.NullPointerException: null
at com.mysql.fabric.jdbc.FabricMySQLDriver.parseFabricURL(FabricMySQLDriver.java:97) ~[mysql-connector-java-5.1.39.jar:5.1.39]
at com.mysql.fabric.jdbc.FabricMySQLDriver.acceptsURL(FabricMySQLDriver.java:93) ~[mysql-connector-java-5.1.39.jar:5.1.39]
at java.sql.DriverManager.getDriver(DriverManager.java:299) ~[na:1.8.0_121]
at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:223) ~[c3p0-0.9.1.2.jar:0.9.1.2]
at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:119) ~[c3p0-0.9.1.2.jar:0.9.1.2]
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111) ~[spring-jdbc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77) ~[spring-jdbc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:326) ~[spring-jdbc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:366) ~[spring-jdbc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.DatabaseLookup.getDatabase(DatabaseLookup.java:72) ~[spring-boot-autoconfigure-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.JpaProperties.determineDatabase(JpaProperties.java:139) ~[spring-boot-autoconfigure-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.jpaVendorAdapter(JpaBaseConfiguration.java:105) ~[spring-boot-autoconfigure-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration$$EnhancerBySpringCGLIB$$eed72d47.CGLIB$jpaVendorAdapter$3(<generated>) ~[spring-boot-autoconfigure-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration$$EnhancerBySpringCGLIB$$eed72d47$$FastClassBySpringCGLIB$$8b0ee726.invoke(<generated>) ~[spring-boot-autoconfigure-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) ~[spring-core-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:356) ~[spring-context-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration$$EnhancerBySpringCGLIB$$eed72d47.jpaVendorAdapter(<generated>) ~[spring-boot-autoconfigure-1.5.1.RELEASE.jar:1.5.1.RELEASE]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:162) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
... 24 common frames omitted
Process finished with exit code 130 (interrupted by signal 2: SIGINT)
看起来您正在使用 Spring Boot，它应该负责为您设置数据库连接。您应该能够完全摆脱DataConfig类，而是在文件src/main/resources/application.properties中提供配置：
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/web_customer_tracker
spring.datasource.username=springstudent
spring.datasource.password=springstudent
spring.datasource.jpa.generate-ddl=true
有关更多信息，请参阅 Spring Boot 关于使用 DBs 的文档：https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-sql.html。您很可能不需要创建自己的DAO，而是使用Spring的存储库功能(您只创建扩展org.springframework.data.jpa.repository.JpaRepository<T, ID>的接口。 例如：
public interface CustomerRepository extends JpaRepository<Customer, Long> {
// Can be empty or you can more queries like findByXXX().
}