MySQL 如何在不依赖数据库的情况下启动 spring-boot 应用程序？
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How to start spring-boot app without depending on Database?
提问by Ripu Daman
I am using "Spring-boot + Hibernate4 + mysql" for my application. As part of which I have a requirement where my sprint-boot app should be able to start even when database is down. Currently it gives the below exception when I try to start my spring boot app without DB being up.
我正在为我的应用程序使用“Spring-boot + Hibernate4 + mysql”。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 应用程序也应该能够启动。目前，当我尝试在没有数据库启动的情况下启动我的 Spring Boot 应用程序时，它给出了以下异常。
I researched a lot and found out that this exception has to do with hibernate.temp.use_jdbc_metadata_defaultsproperty.
我研究了很多，发现这个例外与hibernate.temp.use_jdbc_metadata_defaults财产有关。
I tried setting this in "application.yml" of spring boot but this property's value is not being reflected at runtime.
我尝试在 spring boot 的“application.yml”中设置它，但是在运行时没有反映这个属性的值。
Exception Stack Trace:
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.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.perform(EntityManagerFactoryBuilderImpl.java:850)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.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:
应用程序.yml：
spring:
jpa:
show-sql: true
hibernate:
ddl-auto: none
naming_strategy: org.hibernate.cfg.DefaultNamingStrategy
temp:
use_jdbc_metadata_defaults: false
回答by Ripu Daman
It was indeed a tough nut to crack.
这确实是一个难以破解的难题。
After lot and lot of research and actually debugging the spring-boot, spring, hibernate, tomcat pool, etc to get it done.
经过大量的研究和实际调试 spring-boot、spring、hibernate、tomcat 池等来完成它。
I do think that it will save lot of time for people trying to achieve this type of requirement.
我确实认为这将为尝试实现此类要求的人们节省大量时间。
Below are the settings required to achieve the following requirement
以下是实现以下要求所需的设置
- Spring boot apps will start fine even if DB is down or there is no DB.
- Apps will pick up the connections on the fly as DB comes up which means there is no need to restart the web server or redeploy the apps.
- There is no need to start the tomcat or redeploy the apps, if DB goes down from running state and comes up again.
- 即使数据库关闭或没有数据库，Spring Boot 应用程序也能正常启动。
- 应用程序将在数据库启动时即时获取连接，这意味着无需重新启动 Web 服务器或重新部署应用程序。
- 如果数据库从运行状态下降并再次出现，则无需启动 tomcat 或重新部署应用程序。
application.yml :
应用程序.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
回答by Stephane Nicoll
I am answering here and will close the issue that you have cross-posted
我在这里回答并将关闭您交叉发布的问题
Any "native" property of the JPA implementation (Hibernate) can be set using the spring.jpa.propertiesprefix as explained here
JPA 实现（休眠）的任何“本机”属性都可以使用spring.jpa.properties前缀设置，如此处所述
I haven't looked much further in the actual issue here but to answer this particular question, you can set that hibernate key as follows
我没有进一步研究这里的实际问题，但要回答这个特定问题，您可以按如下方式设置该休眠键
spring.jpa.properties.hibernate.temp.use_jdbc_metadata_defaults
回答by Percy Vega
Adding this alone worked for me:
单独添加这个对我有用：
spring.jpa.properties.hibernate.dialect: org.hibernate.dialect.Oracle10gDialect
Just replace the last part with your database dialect.
只需用您的数据库方言替换最后一部分。
回答by selami tastan
The solution is really useful for me. Thanks i used file "application.properties" includes following lines:
该解决方案对我来说非常有用。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
But, you can not use @Transactional annotation at class level
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 ...
}
回答by smartwjw
Add following config should be work:
添加以下配置应该可以工作：
spring.jpa.database-platform: org.hibernate.dialect.MySQL5Dialect
spring.jpa.database-platform: org.hibernate.dialect.MySQL5Dialect
