PersistenceException:找不到用于为名为default的持久性单元生成架构的持久性提供程序

Question

我试图建立一个gradle任务，运行一个旨在生成SQL模式的java主类。

我没有毅力。xml配置文件。

以下是我的配置和代码：

我的gradle任务：

task JpaSchemaExport(type: JavaExec){
       description "Exports Jpa schema"
       dependsOn compileJava
       main = "com.bignibou.tools.jpa.JpaSchemaExport"
       classpath = sourceSets.main.runtimeClasspath + configurations.compile
    }

我的导出实用程序：

public class JpaSchemaExport {

    public static void main(String[] args) throws IOException {
        // execute(args[0], args[1]);
        execute("default", "build/schema.sql");
        System.exit(0);
    }

    public static void execute(String persistenceUnitName, String destination) {
        final Properties persistenceProperties = new Properties();

        // XXX force persistence properties : remove database target
        persistenceProperties.setProperty(org.hibernate.cfg.AvailableSettings.HBM2DDL_AUTO, "");
        persistenceProperties.setProperty(AvailableSettings.SCHEMA_GEN_DATABASE_ACTION, "none");

        // XXX force persistence properties : define create script target from metadata to destination
        // persistenceProperties.setProperty(AvailableSettings.SCHEMA_GEN_CREATE_SCHEMAS, "true");
        persistenceProperties.setProperty(AvailableSettings.SCHEMA_GEN_SCRIPTS_ACTION, "create");
        persistenceProperties.setProperty(AvailableSettings.SCHEMA_GEN_CREATE_SOURCE, "metadata");
        persistenceProperties.setProperty(AvailableSettings.SCHEMA_GEN_SCRIPTS_CREATE_TARGET, destination);

        Persistence.generateSchema(persistenceUnitName, persistenceProperties);
    }
}

我的数据配置：

@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
    LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
    emf.setPackagesToScan("com.bignibou.domain");
    emf.setDataSource(dataSource);
    emf.setPersistenceProvider(new HibernatePersistenceProvider());
    emf.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
    emf.setJpaPropertyMap(propertiesMap());
    return emf;
}

private Map<String, String> propertiesMap() {
    Map<String, String> propertiesMap = new HashMap<>();
    propertiesMap.put("hibernate.dialect", hibernateDialect);
    propertiesMap.put("hibernate.hbm2ddl.auto", hibernateHbm2ddlAuto);
    propertiesMap.put("hibernate.ejb.naming_strategy", hibernateEjbNamingStrategy);
    propertiesMap.put("hibernate.connection.charSet", hibernateConnectionCharset);
    propertiesMap.put("hibernate.show_sql", hibernateLogSqlInfo);
    propertiesMap.put("hibernate.format_sql", hibernateLogSqlInfo);
    propertiesMap.put("hibernate.use_sql_comments", hibernateLogSqlInfo);
    propertiesMap.put("hibernate.generate_statistics", hibernateGenerateStatistics);
    propertiesMap.put("hibernate.cache.use_second_level_cache", hibernateCacheUseSecondLevelCache);
    propertiesMap.put("hibernate.cache.region.factory_class", "org.hibernate.cache.ehcache.SingletonEhCacheRegionFactory");
    propertiesMap.put("javax.persistence.sharedCache.mode", "ENABLE_SELECTIVE");
    return propertiesMap;
}

以下是我得到的一个例外：

Exception in thread "main" javax.persistence.PersistenceException: No persistence provider found for schema generation for persistence-unit named default
 at javax.persistence.Persistence.generateSchema(Persistence.java:93)
 at com.bignibou.tools.jpa.JpaSchemaExport.execute(JpaSchemaExport.java:31)
 at com.bignibou.tools.jpa.JpaSchemaExport.main(JpaSchemaExport.java:14)

编辑：我确实收到了警告：

:bignibou-server:JpaSchemaExport
2015-05-16 14:46:44,423 [main] WARN  org.hibernate.ejb.HibernatePersistence - HHH015016: Encountered a deprecated javax.persistence.spi.PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.hibernate.jpa.HibernatePersistenceProvider] instead.
2015-05-16 14:46:44,423 [main] WARN  org.hibernate.ejb.HibernatePersistence - HHH015016: Encountered a deprecated javax.persistence.spi.PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.hibernate.jpa.HibernatePersistenceProvider] instead.
2015-05-16 14:46:44,423 [main] WARN  org.hibernate.ejb.HibernatePersistence - HHH015016: Encountered a deprecated javax.persistence.spi.PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.hibernate.jpa.HibernatePersistenceProvider] instead.
Exception in thread "main" javax.persistence.PersistenceException: No persistence provider found for schema generation for persistence-unit named default
 at javax.persistence.Persistence.generateSchema(Persistence.java:93)
 at com.bignibou.tools.jpa.JpaSchemaExport.execute(JpaSchemaExport.java:32)
 at com.bignibou.tools.jpa.JpaSchemaExport.main(JpaSchemaExport.java:14)
:bignibou-server:JpaSchemaExport FAILED 

Answer 1

似乎Persistence.generate模式（）使用了持有持久性提供商ResolverHolder的持久性提供商Resolver来获取所有可用的持久性提供商的列表。也许你应该尝试实现你自己的PeristextProviderResolver（只有2个方法），在调用Persistence.generate模式（）之前返回你想要使用的方法（org.hibernate.jpa.HibernatePeristextProvider）。

PersistenceProviderResolverHolder.setPersistenceProviderResolver(new PersistenceProviderResolver() {

    public List<PersistenceProvider> getPersistenceProviders() {
        return Collections.singletonList(new HibernatePersistenceProvider());
    }

    public void clearCachedProviders() {}
});

Answer 2

你的代码非常好而且干净。服务器启动时是否有任何其他警告，如log4j属性丢失。。等

我认为这个问题与缺少jar或类路径条目有关，尽管对此不确定。

Answer 3

就我从代码中看到的情况来看，您的JpaSchemaExport没有在Spring上下文中执行。

当您从Gradle或命令行运行JpaSchemaExport时，您将创建自己的EntityManager，它与Spring无关，并寻找持久性。xml文件，位于META-INF目录中。对于Spring Boot应用程序，不需要此文件，因此可能不存在。

当我运行与您的JpaSchemaExport类似的东西时，输出类似

[main] INFO  o.h.j.b.i.PersistenceXmlParser - HHH000318: Could not find any META-INF/persistence.xml file in the class path
[main] DEBUG o.h.jpa.HibernatePersistenceProvider - Located and parsed 0  persistence units; checking each 
[main] DEBUG o.h.jpa.HibernatePersistenceProvider - Found no matching persistence units Exception in thread "main"
javax.persistence.PersistenceException: No persistence provider found
for schema generation for persistence-unit named default    at
javax.persistence.Persistence.generateSchema(Persistence.java:93)   at
com.example.springboot.jpa.JpaSchemaExport.execute(JpaSchemaExport.java:42)
    at
com.example.springboot.jpa.JpaSchemaExport.main(JpaSchemaExport.java:14)

Spring Boot命令行应用程序（具有Spring上下文的应用程序）类似于：

@SpringBootApplication
public class Application implements CommandLineRunner {


    public static void main(String[] args) {
        SpringApplication.run(Application.class);
    }

    @Override
    public void run(String... strings) throws Exception {

    }

}

i、 e.您的JpaSchemaExport可以重写为

@SpringBootApplication
public class JpaSchemaExport implements CommandLineRunner {


    public static void main(String[] args) {
        // maybe activate a special spring profile to enable 
        // "hibernate.hbm2ddl.auto", validate | update | create | create-drop
        // AvailableSettings.SCHEMA_GEN_DATABASE_ACTION, "none" 
        // AvailableSettings.SCHEMA_GEN_CREATE_SCHEMAS, "true"
        // AvailableSettings.SCHEMA_GEN_SCRIPTS_ACTION, "create"
        // AvailableSettings.SCHEMA_GEN_CREATE_SOURCE, "metadata"
        // AvailableSettings.SCHEMA_GEN_SCRIPTS_CREATE_TARGET, destination

        SpringApplication.run(JpaSchemaExport.class);
    }

    @Override
    public void run(String... strings) throws Exception {
       // nothing needed here 
    }

}

作为替代方案，您可以创建META-INF/持久性。xml可供Spring Boot应用程序以及JpaSchemaExport使用。