问题
I have tried to set up a gradle task that runs a java main class that is intended to generate a SQL schema.
I have no persistence.xml configuration file.
Here is my configuration and code:
My gradle task:
task JpaSchemaExport(type: JavaExec){
description "Exports Jpa schema"
dependsOn compileJava
main = "com.bignibou.tools.jpa.JpaSchemaExport"
classpath = sourceSets.main.runtimeClasspath + configurations.compile
}
My export utility:
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);
}
}
My data configuration:
@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;
}
Here is the exception I get:
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)
edit: I do get warnings indeed:
: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
回答1:
Your JpaSchemaExport is not executed within a Spring Context as far as I can see from your code.
When you run your JpaSchemaExport from Gradle or command line you create your own EntityManager which has nothing to do with Spring and looks for a persistence.xml file in the META-INF directory. For Spring Boot Applications this file is not needed and thus may not exist.
When I run something which looks similar your JpaSchemaExport the output is something like
[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)
A Spring Boot Commandline Application (one that has a Spring Context) looks something like:
@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. your JpaSchemaExport may be rewritten as
@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
}
}
As an alternative you can create a META-INF/persistence.xml which can be used by your Spring Boot application as well as by your JpaSchemaExport.
回答2:
Your code is very good and clean. Is there any other warning on server startup like log4j properties missing .. etc.,
I think the problem is related to some missing jar or classpath entry, though not sure about it.
回答3:
It seems that Persistence.generateSchema() uses PersistenceProviderResolverHolder which holds a PersistenceProviderResolver to get a list of all available PersistenceProviders. Maybe you should try implementing your own PersistenceProviderResolver (only 2 methods) to return the one you want to use (org.hibernate.jpa.HibernatePersistenceProvider) before calling Persistence.generateSchema().
PersistenceProviderResolverHolder.setPersistenceProviderResolver(new PersistenceProviderResolver() {
public List<PersistenceProvider> getPersistenceProviders() {
return Collections.singletonList(new HibernatePersistenceProvider());
}
public void clearCachedProviders() {}
});
回答4:
You would need to set an explicit name for the persistence unit that is created programmatically using the following method and then make sure to call the afterPropertiesSet() method:
emf.setPersistenceUnitName( "puname" );
...
emf.afterPropertiesSet();
Refer to your persistence unit using this name instead of "default"
回答5:
Generating schema with Spring Boot app:
import org.hibernate.jpa.AvailableSettings;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import java.util.Properties;
@SpringBootApplication
public class JpaSchemaExport implements CommandLineRunner {
@Autowired LocalContainerEntityManagerFactoryBean entityManagerFactory;
public static void main(String... args) {
new SpringApplicationBuilder(JpaSchemaExport.class).run(args);
}
@Override
public void run(String... args) throws Exception {
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, "./generated-schema.ddl");
// generate sql with semicolon - workaround for HHH-10278
String systemLineSeparator = System.getProperty("line.separator");
System.setProperty("line.separator", ';' + systemLineSeparator);
// get a persistence provider from spring context
entityManagerFactory.getJpaVendorAdapter().getPersistenceProvider().generateSchema(entityManagerFactory.getPersistenceUnitInfo(), persistenceProperties);
System.setProperty("line.separator", systemLineSeparator);
System.exit(0);
}
}
来源：https://stackoverflow.com/questions/30225183/persistenceexception-no-persistence-provider-found-for-schema-generation-for-pe