我正在使用＆＃34; Spring-boot + Hibernate4 + mysql＆＃34;为我的申请。作为其中的一部分，我有一个要求，即使数据库关闭，我的sprint-boot应用程序应该能够启动。目前，当我尝试在没有DB启动的情况下启动Spring启动应用程序时，它会给出以下异常。
我研究了很多，发现这个例外与hibernate.temp.use_jdbc_metadata_defaults属性有关。
我尝试在＆＃34; application.yml＆＃34;春季启动，但此属性的值未在运行时反映。
异常堆栈跟踪：
2014-05-25 04:09:43.193 INFO 59755 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {4.0.4.Final}
2014-05-25 04:09:43.250 WARN 59755 --- [ main] o.h.e.jdbc.internal.JdbcServicesImpl : HHH000342: Could not obtain connection to query metadata : Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
2014-05-25 04:09:43.263 INFO 59755 --- [ main] o.apache.catalina.core.StandardService : Stopping service Tomcat
Error starting ApplicationContext. To display the auto-configuration report enabled debug logging (start with --debug)
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1553)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:973)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:750)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:120)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:648)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:311)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:909)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:898)
at admin.Application.main(Application.java:36)
Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set
at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.determineDialect(DialectFactoryImpl.java:104)
at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:71)
at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:205)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:89)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:206)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:178)
at org.hibernate.cfg.Configuration.buildTypeRegistrations(Configuration.java:1885)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1843)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:850)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:843)
at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:399)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:842)
at org.hibernate.jpa.HibernatePersistenceProvider.createContainerEntityManagerFactory(HibernatePersistenceProvider.java:150)
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:336)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1612)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1549)
... 15 more
application.yml：
spring:
jpa:
show-sql: true
hibernate:
ddl-auto: none
naming_strategy: org.hibernate.cfg.DefaultNamingStrategy
temp:
use_jdbc_metadata_defaults: false
答案 0 :(得分：49)
破解确实是一个艰难的难题。
经过大量的研究和实际调试spring-boot，spring，hibernate，tomcat pool等来完成它。
我认为这会为试图达到这种要求的人节省大量时间。
以下是达到以下要求所需的设置
application.yml：
spring:
datasource:
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/schema
username: root
password: root
continueOnError: true
initialize: false
initialSize: 0
timeBetweenEvictionRunsMillis: 5000
minEvictableIdleTimeMillis: 5000
minIdle: 0
jpa:
show-sql: true
hibernate:
ddl-auto: none
naming_strategy: org.hibernate.cfg.DefaultNamingStrategy
properties:
hibernate:
dialect: org.hibernate.dialect.MySQL5Dialect
hbm2ddl:
auto: none
temp:
use_jdbc_metadata_defaults: false
答案 1 :(得分：10)
我在这里回答并将关闭the issue that you have cross-posted
可以使用spring.jpa.properties前缀explained here
我在这里的实际问题上没有进一步了解，但为了回答这个问题，您可以将hibernate键设置如下
spring.jpa.properties.hibernate.temp.use_jdbc_metadata_defaults
答案 2 :(得分：6)
单独添加此功能对我有用：
spring.jpa.properties.hibernate.dialect: org.hibernate.dialect.Oracle10gDialect
只需用数据库方言替换最后一部分。
答案 3 :(得分：0)
该解决方案对我来说真的很有用。谢谢 我使用的文件“ application.properties”包括以下几行：
app.sqlhost=192.168.10.11
app.sqlport=3306
app.sqldatabase=logs
spring.main.web-application-type=none
# Datasource
spring.datasource.url=jdbc:mysql://${app.sqlhost}:${app.sqlport}/${app.sqldatabase}
spring.datasource.username=user
spring.datasource.password=password
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect
spring.jpa.properties.hibernate.hbm2dll.auto = none
spring.jpa.properties.hibernate.temp.use_jdbc_metadata_defaults = false
spring.datasource.continue-on-error=true
spring.datasource.initialization-mode=never
spring.datasource.hikari.connection-timeout=5000
spring.datasource.hikari.idle-timeout=600000
spring.datasource.hikari.max-lifetime=1800000
spring.datasource.hikari.initialization-fail-timeout= -1
spring.jpa.hibernate.use-new-id-generator-mappings=true
spring.jpa.hibernate.ddl-auto=none
spring.jpa.show-sql=true
spring.output.ansi.enabled=always
但是，您不能在类级别使用@Transactional注释
@Service
//@Transactional //do not use to touch the Repository
@EnableAsync
@Scope( proxyMode = ScopedProxyMode.TARGET_CLASS )
public class LogService {
.... }
@Async
@Transactional // you can use at function level
public void deleteLogs(){
logRepository.deleteAllBy ...
}
答案 4 :(得分：-1)
添加以下配置应该有效：
spring.jpa.database-platform: org.hibernate.dialect.MySQL5Dialect