使用自定义分隔符通过Spring Boot生成DDL

Z时代
2024-01-10
分类：问答

我想使用Spring Boot" title="Spring Boot">Spring Boot v1.4.3和JPA-Hibernate 5.0.11生成create和drop ddl脚本。

我发现的大多数答案都使用这些javax.persistence.schema-generation属性。

这种方法的问题是它输出不带分隔符的sql语句。例如

create table ... (...)
create table ... (...)

我希望它输出带有定界符的语句 ;

create table ... (...);
create table ... (...);

但是我找不到任何javax.persistence.schema-generation属性来配置它。

因此，我想使用SchemaExportfromhibernate模式，因为您可以设置delimiter属性。但是要创建一个，SchemaExport我需要一个MetadataImplementor（不受影响的api）。

我不知道如何MetadataImplementor从Spring Boot。

有谁知道是否有

javax.persistence.schema-generation定义分隔符的属性

或如何创建SchemaExport（获取依赖项）

或有其他解决方案？

这是一些您可以使用的代码

@SpringBootApplication
@ComponentScan(basePackageClasses = Application.class)
@EntityScan(basePackageClasses = User.class)
public class Application {
    @Bean
    public ApplicationRunner getApplicationRunner() {
        return new ApplicationRunner() {
            public void run(ApplicationArguments args) throws Exception {
                // MetadataImplementor metadataImplementor = ???;
                // new SchemaExport(metadataImplementor);
            }
        };
    }
    public static void main(String[] args) {
        SpringApplication application = new SpringApplication(Application.class);
        application.run(args);
    }
}

回答：

@Entity
public class User {
    @Id
    @GeneratedValue
    private Long id;
    private String name;
    public Long getId() {
        return id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

回答：

@Entity
public class Person {
    @Id
    @GeneratedValue
    private Long id;
    private String name;
    public Long getId() {
        return id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

回答：

spring.jpa.properties.javax.persistence.schema-generation.create-source=metadata spring.jpa.properties.javax.persistence.schema-generation.scripts.action=create spring.jpa.properties.javax.persistence.schema-generation.scripts.create-target=create.sql

回答：

<properties>
    <spring.boot.version>1.4.3.RELEASE</spring.boot.version>
</properties>
<dependencyManagement>
    <dependencies>
        <dependency>
            <!-- Import dependency management from Spring Boot -->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>${spring.boot.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>
<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
    </dependency>
</dependencies>

我只是用hibernate尝试了上面的代码5.0.11.Final。您唯一需要更改的是

SchemaExport schemaExport = new SchemaExport((MetadataImplementor) metadata);
schemaExport.setDelimiter(";");
schemaExport.setFormat(false);
schemaExport.setOutputFile(dropAndCreateDdlFile.getAbsolutePath());
schemaExport.execute(true, false, false, false);

或者当然让Java配置返回MetadataImplementor而不是Metadata并更改ApplicationRunner构造函数参数。

回答：

最后，经过大量调查，我认为我找到了一个使用公共API的简单解决方案。我发现的解决方案使用hibernate5.2（更具体5.2.6.Final）。但我认为它也可以适应5.0

这是我的Spring Java配置

@Configuration
@AutoConfigureAfter({ HibernateJpaAutoConfiguration.class })
public class HibernateJavaConfig {
    @ConditionalOnMissingBean({ Metadata.class })
    @Bean
    public Metadata getMetadata(StandardServiceRegistry standardServiceRegistry,
            PersistenceUnitInfo persistenceUnitInfo) {
        MetadataSources metadataSources = new MetadataSources(standardServiceRegistry);
        List<String> managedClassNames = persistenceUnitInfo.getManagedClassNames();
        for (String managedClassName : managedClassNames) {
            metadataSources.addAnnotatedClassName(managedClassName);
        }
        Metadata metadata = metadataSources.buildMetadata();
        return metadata;
    }
    @ConditionalOnMissingBean({ StandardServiceRegistry.class })
    @Bean
    public StandardServiceRegistry getStandardServiceRegistry(JpaProperties jpaProperties) {
        StandardServiceRegistryBuilder ssrb = new StandardServiceRegistryBuilder();
        Map<String, String> properties = jpaProperties.getProperties();
        ssrb.applySettings(properties);
        StandardServiceRegistry ssr = ssrb.build();
        return ssr;
    }
    @ConditionalOnMissingBean({ PersistenceUnitInfo.class })
    @Bean
    public PersistenceUnitInfo getPersistenceUnitInfo(EntityScanPackages entityScanPackages) {
        List<String> packagesToScan = entityScanPackages.getPackageNames();
        DefaultPersistenceUnitManager persistenceUnitManager = new DefaultPersistenceUnitManager();
        String[] packagesToScanArr = (String[]) packagesToScan.toArray(new String[packagesToScan.size()]);
        persistenceUnitManager.setPackagesToScan(packagesToScanArr);
        persistenceUnitManager.afterPropertiesSet();
        PersistenceUnitInfo persistenceUnitInfo = persistenceUnitManager.obtainDefaultPersistenceUnitInfo();
        return persistenceUnitInfo;
    }
}

Java配置创建一个Metadatabean。可以在hibernate 5.2中使用此bean执行模式生成。例如

@Component
public class GenerateDDLApplicationRunner implements ApplicationRunner {
    private Metadata metadata;
    public GenerateDDLApplicationRunner(Metadata metadata) {
        this.metadata = metadata;
    }
    public void run(ApplicationArguments args) throws Exception {
        File dropAndCreateDdlFile = new File("drop-and-create.ddl");
        deleteFileIfExists(dropAndCreateDdlFile);
        SchemaExport schemaExport = new SchemaExport();
        schemaExport.setDelimiter(";");
        schemaExport.setFormat(false);
        schemaExport.setOutputFile(dropAndCreateDdlFile.getAbsolutePath());
        schemaExport.execute(EnumSet.of(TargetType.SCRIPT), Action.BOTH, metadata);
    }
    private void deleteFileIfExists(File dropAndCreateDdlFile) {
        if (dropAndCreateDdlFile.exists()) {
            if (!dropAndCreateDdlFile.isFile()) {
                String msg = MessageFormat.format("File is not a normal file {0}", dropAndCreateDdlFile);
                throw new IllegalStateException(msg);
            }
            if (!dropAndCreateDdlFile.delete()) {
                String msg = MessageFormat.format("Unable to delete file {0}", dropAndCreateDdlFile);
                throw new IllegalStateException(msg);
            }
        }
    }
}