即使数据库不存在，也可以使用Hibernate动态创建PostgreSQL数据库

使用H2，

Environment.HBM2DDL_AUTO,"create"

如果数据库尚不存在，则创建数据库。

但是，在Postgres中，不会创建不存在的数据库，因此会引发异常，例如“ DB不存在”。有没有一种方法可以配置POSTGRes按需创建不存在的数据库？

以下配置文件可用于重现该问题：

使用H2可以正常工作：

package test.POSTGRessql;

import java.util.Properties;

import javax.sql.Datasource;

import org.hibernate.cfg.Environment;
import org.springframework.beans.factory.Annotation.Autowired;
import org.springframework.context.Annotation.bean;
import org.springframework.context.Annotation.ComponentScan;
import org.springframework.context.Annotation.Configuration;
import org.springframework.context.Annotation.Propertysource;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.jdbc.datasource.DriveRMANagerDatasource;
import org.springframework.orm.hibernate4.HibernateExceptionTranslator;
import org.springframework.orm.jpa.JpatransactionManager;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntitymanagerFactoryBean;
import org.springframework.orm.jpa.vendor.Database;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformtransactionManager;
import org.springframework.transaction.Annotation.EnabletransactionManagement;

@Configuration
@Propertysource("file:C:/springconfig/qpmlib.properties")
@ComponentScan(basePackages = {"test.POSTGRessql"})
@EnableJpaRepositories(basePackages = { "test.POSTGRessql" })
@EnabletransactionManagement
public abstract class H2DBConfig {

    @Autowired
    org.springframework.core.env.Environment env;

    public static final String db_name = getNewDBName();

    @Bean
    public Datasource datasource() {
        DriveRMANagerDatasource dmds = new DriveRMANagerDatasource();
        dmds.setDriverClassName("org.h2.Driver");
        dmds.setUrl("jdbc:h2:tcp://localhost/~/" + db_name );
        dmds.setUsername(env.getProperty("h2user"));
        dmds.setpassword(env.getProperty("h2pw"));
        return dmds;
    }

    private static String getNewDBName() {
        return "H2DBTest";
    }

    @Bean
    public LocalContainerEntitymanagerFactoryBean entitymanagerFactory() {
        LocalContainerEntitymanagerFactoryBean factory = new LocalContainerEntitymanagerFactoryBean();
        factory.setDatasource(datasource());
        factory.setPersistenceUnitName(db_name);
        factory.setPackagesToScan("test.POSTGRessql");
        factory.setJpaVendorAdapter(jpaAdapter());
        factory.setJpaProperties(jpaProperties());
        factory.afterPropertiesSet();
        return factory;
    }

    @Bean
    public PlatformtransactionManager transactionManager() {
        JpatransactionManager txm = new JpatransactionManager(
                entitymanagerFactory().getObject());
        return txm;
    }

    @Bean
    public JpaVendorAdapter jpaAdapter() {
        HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();
        adapter.setDatabase(Database.H2);
        adapter.setGenerateDdl(true);
        adapter.setShowSql(true);
        return adapter;
    }

    @Bean
    public HibernateExceptionTranslator exceptionTranslator() {
        return new HibernateExceptionTranslator();
    }

    public Properties jpaProperties() {
        Properties properties = new Properties();
        properties.put(Environment.SHOW_SQL,"true");
        properties.put(Environment.HBM2DDL_AUTO,"create");
        properties.put(Environment.DIALECT,"org.hibernate.dialect.H2Dialect");
        return properties;
    }

}

使用PostgreS失败

package test.POSTGRessql;

import java.util.Properties;

import javax.sql.Datasource;

import org.hibernate.cfg.Environment;
import org.springframework.beans.factory.Annotation.Autowired;
import org.springframework.context.Annotation.bean;
import org.springframework.context.Annotation.ComponentScan;
import org.springframework.context.Annotation.Configuration;
import org.springframework.context.Annotation.Propertysource;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.jdbc.datasource.DriveRMANagerDatasource;
import org.springframework.orm.hibernate4.HibernateExceptionTranslator;
import org.springframework.orm.jpa.JpatransactionManager;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntitymanagerFactoryBean;
import org.springframework.orm.jpa.vendor.Database;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformtransactionManager;
import org.springframework.transaction.Annotation.EnabletransactionManagement;

@Configuration
@Propertysource("file:C:/springconfig/qpmlib.properties")
@ComponentScan(basePackages = {"test.POSTGRessql"})
@EnableJpaRepositories(basePackages = { "test.POSTGRessql" })
@EnabletransactionManagement
public abstract class PGDBConfig {

    @Autowired
    org.springframework.core.env.Environment env;

    public static final String db_name = getNewDBName();

    @Bean
    public Datasource datasource() {
        DriveRMANagerDatasource dmds = new DriveRMANagerDatasource();
        dmds.setDriverClassName("org.POSTGResql.Driver");
        dmds.setUrl("jdbc:POSTGResql://localhost:5432/" + db_name);
        dmds.setUsername(env.getProperty("POSTGResuser"));
        dmds.setpassword(env.getProperty("POSTGRespw"));
        return dmds;
    }

    private static String getNewDBName() {
        return "POSTGResDBTest";
    }

    @Bean
    public LocalContainerEntitymanagerFactoryBean entitymanagerFactory() {
        LocalContainerEntitymanagerFactoryBean factory = new LocalContainerEntitymanagerFactoryBean();
        factory.setDatasource(datasource());
        factory.setPersistenceUnitName(db_name);
        factory.setPackagesToScan("test.POSTGRessql");
        factory.setJpaVendorAdapter(jpaAdapter());
        factory.setJpaProperties(jpaProperties());
        factory.afterPropertiesSet();
        return factory;
    }

    @Bean
    public PlatformtransactionManager transactionManager() {
        JpatransactionManager txm = new JpatransactionManager(
                entitymanagerFactory().getObject());
        return txm;
    }

    @Bean
    public JpaVendorAdapter jpaAdapter() {
        HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();
        adapter.setDatabase(Database.POSTGRESQL);
        adapter.setGenerateDdl(true);
        adapter.setShowSql(true);
        return adapter;
    }

    @Bean
    public HibernateExceptionTranslator exceptionTranslator() {
        return new HibernateExceptionTranslator();
    }

    public Properties jpaProperties() {
        Properties properties = new Properties();
        properties.put(Environment.SHOW_SQL,"org.hibernate.dialect.POSTGReSQL9Dialect");
        return properties;
    }
}