Spring Boot不会在状态表上建立JPA数据库连接

Question

I have a Spring Boot + Groovy application that requires the Database Connection to be made per-session or per-tenant basis. When implementing the solution using Hibernate only it works, however when adding spring-boot-starter-data-jpa and switching to JPA a database connection is attempted on start up which fails because there is no connection settings defined yet.

I have a gradle dependencies block that looks like this:

dependencies {
    compile "org.springframework.boot:spring-boot-starter-web"
    compile "org.springframework.boot:spring-boot-starter-data-jpa"

    compile "org.codehaus.groovy:groovy-all:2.3.3"

    compile "org.springframework:spring-core:${springVersion}"
    compile "org.springframework:spring-webmvc:${springVersion}"
    compile "org.springframework:spring-orm:${springVersion}"
    compile "org.springframework:spring-aop:${springVersion}"
    compile "org.springframework:spring-context-support:${springVersion}"
    compile "org.hibernate:hibernate-entitymanager:${hibernateVersion}"
    compile "com.oracle:ojdbc7:12.1.0.1"
    compile "org.apache.commons:commons-dbcp2:2.0.1"
    compile "cglib:cglib:3.1"
...
}

And my Application.groovy looks like this:

@Configuration
@EnableAutoConfiguration
@ComponentScan
@EnableTransactionManagement
class Application
{
    final Logger aLog = Logger.getLogger(Application.class)

    @Autowired
    DatabaseSettings dbSettings

    @Bean(destroyMethod="close")
    @Lazy
    public DataSource dataSource()
    {
        aLog.info ">>>>>>>>>>>>> CREATING DATA SOURCE <<<<<<<<<<<<<<<"
        new BasicDataSource(driverClassName: dbSettings.driverClassName,    
                            url: dbSettings.dbUrl, username: dbSettings.dbUser, password: dbSettings.dbPass, 
                            maxTotal: 10, maxWaitMillis: 10000, maxIdle:10, defaultAutoCommit:false)
    }

    @Bean
    @Lazy
    public LocalContainerEntityManagerFactoryBean entityManagerFactory()
    {
        Properties hqlProps =   ['hibernate.dialect': this.dbSettings.dialect, 'hibernate.temp.use_jdbc_metadata_defaults': false,
                                 'hibernate.show_sql': this.dbSettings.showSql, 'hibernate.format_sql': this.dbSettings.formatSql, 
                                 'hibernate.use_sql_comments': this.dbSettings.useSqlComments] as Properties

        aLog.info ">>>>>>>>>>>>> CREATING ENTITY MANAGER FACTORY <<<<<<<<<<<<<<<"

        LocalContainerEntityManagerFactoryBean em   =   new LocalContainerEntityManagerFactoryBean()

        em.setDataSource(dataSource())
        em.setPackagesToScan(this.dbSettings.getPackagesToScan())
        em.setJpaVendorAdapter(new HibernateJpaVendorAdapter())
        em.setJpaProperties(hqlProps)
        em
    }

    @Bean
    @Lazy
    public JpaTransactionManager transactionManager()
    {
        aLog.info ">>>>>>>>>>>>> CREATING TRANSACTION MANAGER <<<<<<<<<<<<<<<"
        new JpaTransactionManager(entityManagerFactory: entityManagerFactory().getObject())     
    }

    static void main(args) throws Exception
    {
        ApplicationContext appCtx = SpringApplication.run(Application.class, args)
    }
}

I have removed the Scopes configuration for simplicity.

The point is that all relevant Beans are annotated as @Lazy, however at start up I see the messages regarding the Data Source and Entity Manager being created.

Debugging the code looks like at some point HibernateJpaAutoConfigurer is called and this class have @Autowired the DataSource in thus causing the instantiation of these beans on start up.

My question is: How can I prevent Spring Boot to attempt a Database Connection on start up?

Thanks in advance

Answer 1

I think I found a work around:

Looking at spring-boot-starte-data-jpa's pom.xml I found that it depends on spring-data-jpa, so I decided to replace the starter-data-jpa with just spring-data-jpa with partial results. Still I couldn't get session scopes or custom scopes to delay the initialization of components, it wouldn't even compile actually. So in order to get everything to work nice I needed to all aspectjweaver too.

So now my dependencies look like:

dependencies {
compile "org.springframework.boot:spring-boot-starter-web"
// 
compile "org.springframework.data:spring-data-jpa:1.7.1.RELEASE"
compile "org.aspectj:aspectjweaver:1.8.4"

compile "org.codehaus.groovy:groovy-all:2.3.3"
... }

So, if now I annotate DataSource creation with @Scope(value="session", proxyMode=ScopedProxyMode.TARGET_CLASS) or even with a Custom Scope, the instantiation happens after the startup process, as expected.

However it feels like defeating the purpose of using SpringBoot, I still think there should be a way to configure SpringBoot in such a way that I can achieve same results.