在Hibernate表和flyway中使用spel

问题描述 投票:0回答:2

给予spring boot应用的application.yml文件中的这样一个SPEL表达式--。

database:
      schema: '#{"${ENV_VAR:}".equals("")?"DEMO":"DEMO_${ENV_VAR:}"}'

下面的代码中,如果${ENV_VAR} = XYZ,它就会打印出替代值,比如DEMO_XYZ DEMO。

@Value("${database.schema}")
private String schema;

但一个带有Table注释的Hibernate JPA实体无法将这里启用的SPEL变量作为模式--

@Entity
@Table(name = "TABLE_A", schema="${database.schema}") // prints whole spel expression here 
public class TableA { ...

即使在下面,也不能使用默认模式的SPEL的替代值--------。

spring:  
  jpa:
    show-sql: true
    properties:
      hibernate:
        default_schema: ${database.schema} // prints whole value here as well

似乎flyway不能使用在application.yml中已经定义好的SPEL变量。

spring:  
  flyway:
    jdbc-url: ...
    schemas: ${database.schema}

有什么办法 hibernate.default_schemaflyway.schemas 接受SPEL表达式,如 ${database.schema} 在同一个YML文件中?

java spring hibernate spring-boot spring-el
2个回答
1
投票

Spring Boot实际上不支持SpEL application.yml.

如果你注射的是 Environment

String property = env.getProperty("database.schema");

你会看到占位符被解析了,但SpEL没有被解析。

@Value 必须有一些额外的逻辑来解决SpEL的进一步下游。


0
投票

通过像下面这样以程序化的方式创建Hibernate JPA beans和Flyway beans来解决这个问题,而不是使用YML,因为只有@Value注解能够读取SPEL。

database:
      schema: '#{"${ENV_VAR:}".equals("")?"DEMO":"DEMO_${ENV_VAR:}"}'

数据库配置


@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = {"com.xyz"})
@EntityScan(basePackages = {"com.xyz"})
public class DbConfig
{
    @Value("${database.schema}")
    private String schema; 

    @Bean
    public EntityManager entityManager(SessionFactory sessionFactory)
    {
        return sessionFactory.createEntityManager();
    }

    @Bean
    public PlatformTransactionManager transactionManager()
    {
        return new JpaTransactionManager();
    }

    @Bean
    public HikariConfig hikariConfig()
    {
        HikariConfig hikariConfig = new HikariConfig();
        hikariConfig.setDriverClassName("net.client.jdbc.Driverx");
        hikariConfig.setJdbcUrl(url);
        Properties props = new Properties();
        props.put("user", user);
        props.put("password", password);
        props.put("db", db);
        props.put("schema", schema);  // SCHEMA is from SPEL
        hikariConfig.setDataSourceProperties(props);
        return hikariConfig;
    }

    @Bean
    public DataSource dataSource(HikariConfig hikariConfig)
    {
        HikariDataSource dataSource = new HikariDataSource(hikariConfig);
        return dataSource;
    }

    @Bean
    public LocalSessionFactoryBean entityManagerFactory(DataSource snowflakeDataSource)
    {
        LocalSessionFactoryBean localSessionFactoryBean = new LocalSessionFactoryBean();
        localSessionFactoryBean.setDataSource(dataSource);
        localSessionFactoryBean.setPackagesToScan("com.xyz");
        Properties properties = new Properties();
        properties.setProperty("hibernate.default_schema", schema);
        properties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect");
        properties.setProperty("hibernate.show_sql", "true");
        properties.setProperty("hibernate.format_sql", "true");
        localSessionFactoryBean.setHibernateProperties(properties);
        return localSessionFactoryBean;
    }

飞航配置

    @Value("${database.schema}")
    private String schema;

    @Bean
    public Flyway flyway(DataSource dataSource)
    {
        Flyway flyWay = Flyway.configure()
            .dataSource(dataSource)
            .locations("classpath:/somefolder/migrations")
            .schemas(schema)  // SCHEMA is from SPEL
            .baselineVersion("1.0")
            .sqlMigrationPrefix("V")
            .sqlMigrationSuffixes(".sql")
            .placeholders(Map.of("key1", value1,
                "key2", value2))
            .placeholderReplacement(true)
            .placeholderPrefix("%")
            .placeholderSuffix("%")
            .load();
        flyWay.migrate();
        return flyWay;
    }
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