Hibernate：外部连接配置文件

Question

我目前在我的 Spring Web 应用程序类路径中有我的 Hibernate 配置文件 hibernate.cfg.xml，并使用 Maven 资源插件为我的开发和生产数据库设置不同的值，如下所示：

资源/hibernate.cfg.xml：

<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD//EN"
        "../hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">@hibernate.connection.driver_class@</property>
        <property name="hibernate.connection.url">@hibernate.connection.url@</property>
        <property name="hibernate.dialect">@hibernate.dialect@</property>
        <property name="hibernate.default_schema">@hibernate.default_schema@</property>
        <property name="hibernate.connection.username">@hibernate.connection.username@</property>
        <property name="hibernate.connection.password">@hibernate.connection.password@</property>
        <property name="hibernate.connection.requireSSL">false</property>
        <property name="hibernate.connection.autoReconnect">true</property>
        <property name="hibernate.enable_lazy_load_no_trans">true</property>
        <!--<property name="hbm2ddl.auto">update</property>-->
        <property name="hibernate.show_sql">false</property>
        <property name="hibernate.format_sql">false</property>
        <property name="hibernate.connection.CharSet">utf8</property>
        <property name="hibernate.connection.characterEncoding">utf8</property>
        <property name="hibernate.connection.useUnicode">true</property>

        <property name="hibernate.connection.provider_class">org.hibernate.c3p0.internal.C3P0ConnectionProvider</property>
        <property name="hibernate.c3p0.min_size">1</property>
        <property name="hibernate.c3p0.max_size">50</property>
        <property name="hibernate.c3p0.timeout">120</property>
        <property name="hibernate.c3p0.max_statements">50</property>
    </session-factory>
</hibernate-configuration>

pom.xml（示例）：

    <profiles>
        <profile>
            <id>dev</id>
            <activation>
                <activeByDefault>true</activeByDefault>
            </activation>
            <properties>
                <hibernate.connection.driver_class>com.mysql.cj.jdbc.Driver</hibernate.connection.driver_class>
                <hibernate.connection.url>jdbc:mysql://localhost:3306/dev_db</hibernate.connection.url>
                <hibernate.dialect>org.hibernate.dialect.MySQL5Dialect</hibernate.dialect>
                <hibernate.default_schema></hibernate.default_schema>
                <hibernate.connection.username>dev_username</hibernate.connection.username>
                <hibernate.connection.password>dev_password</hibernate.connection.password>
            </properties>
        </profile>
        <profile>
            <id>deploy</id>
            <properties>
                <hibernate.connection.driver_class>com.mysql.cj.jdbc.Driver</hibernate.connection.driver_class>
                <hibernate.connection.url>jdbc:mysql://localhost:3306/deploy_db</hibernate.connection.url>
                <hibernate.dialect>org.hibernate.dialect.MySQL5Dialect</hibernate.dialect>
                <hibernate.default_schema></hibernate.default_schema>
                <hibernate.connection.username>deploy_username</hibernate.connection.username>
                <hibernate.connection.password>deploy_password</hibernate.connection.password>
            </properties>
        </profile>
    </profiles>

这些设置由LocalSessionFactoryBean 加载，如下所示：

    @Bean( name = "sessionFactory" )
    public LocalSessionFactoryBean sessionFactory() {
        LocalSessionFactoryBean localSessionFactoryBean = new LocalSessionFactoryBean();
        localSessionFactoryBean.setDataSource( dataSource() );
        localSessionFactoryBean.setConfigLocation( new ClassPathResource( "hibernate.cfg.xml" ) );
        localSessionFactoryBean.setPackagesToScan( "org.example" );

        return localSessionFactoryBean;
    }

但现在我需要将软件发送给显然不希望我知道他们的数据库连接属性的客户，所以我想将这些属性从我的项目中移出到某个本地资源（如 C:\MyEpicProgram\db.properties），这将在每个环境（我的本地、客户端的测试服务器、客户端的部署服务器等）中单独设置，并通过 JVM 参数（如-DdbConfigPath=C:\MyEpicProgram\db.properties）链接到我的应用程序

所以我得到类似的东西： db.properties：

hibernate.connection.driver_class com.mysql.cj.jdbc.Driver
hibernate.connection.url jdbc:mysql://localhost:3306/client_db
hibernate.dialect org.hibernate.dialect.MySQL5Dialect
hibernate.default_schema
hibernate.connection.username client_username
hibernate.connection.password client_password

这些将在该环境中的项目启动时自动使用。我怎样才能做到这一点？我一直在尝试修改我的会话工厂 bean 以手动设置每个参数，但到目前为止未能正确执行。

Answer 1

您可以尝试这样做。但是，实际上并不建议这样做，因为您将该文件耦合到您的应用程序。

@Configuration
public class Configuration {
    @Autowired
    private Environment environment;

    @Bean
    public LocalSessionFactoryBean localSessionFactoryBean() {
        LocalSessionFactoryBean localSessionFactoryBean = new LocalSessionFactoryBean();
        localSessionFactoryBean.setDataSource( dataSource() );
        localSessionFactoryBean.setConfigLocation( new ClassPathResource( "hibernate.cfg.xml" ) );
        localSessionFactoryBean.setPackagesToScan( "org.example" );

        Properties properties = new Properties();
        properties.load(new FileInputStream(environment.getProperty("dbConfigPath")));

        localSessionFactoryBean.setHibernateProperties(properties);
        
        return localSessionFactoryBean;
    }
}

您可以做的是使用环境变量来定义您的 Hibernate 属性，如 here 所述。

Answer 2

所以，我从 Flavalacious 的建议中汲取灵感，这样解决了我的问题：

@Configuration
public class DBConfig {
    private final Logger logger = Logger.getLogger( this.getClass() );

    private String dataSourceDriverClass;
    private String dataSourceDialect;
    private String dataSourceUrl;
    private String dataSourceUsername;
    private String dataSourcePassword;

    public DBConfig() {
        Properties jdbcProperties = new Properties();

        if ( System.getProperty( "dbConfigPath" ) == null )
            throw new IllegalStateException( "Property -DdbConfigPath must be provided in VM options." );

        try ( InputStream fileStream = new FileInputStream( filePath ) ) {
            // load properties from file
            jdbcProperties.load( fileStream );

            // setting properties from file to local variables for usage in various beans
            dataSourceUrl = jdbcProperties.getProperty( "url" );
            dataSourceUsername = jdbcProperties.getProperty( "username" );
            dataSourcePassword = jdbcProperties.getProperty( "password" );
            dataSourceDriverClass = jdbcProperties.getProperty( "driverClass" );
            dataSourceDialect = jdbcProperties.getProperty( "dialect" );
        } catch ( IOException e ) {
            logger.error( "Couldn't load JDBC properties." );
        }
    }

    @Bean(name = "dataSource")
    public DriverManagerDataSource dataSource() {
        DriverManagerDataSource driverManagerDataSource = new DriverManagerDataSource();

        // use loaded parameters to configure datasource
        driverManagerDataSource.setDriverClass( dataSourceDriverClass );
        driverManagerDataSource.setJdbcUrl( dataSourceUrl );
        driverManagerDataSource.setUser( dataSourceUsername );
        driverManagerDataSource.setPassword( dataSourcePassword );
        return driverManagerDataSource;
    }

    @Bean( name = "sessionFactory" )
    public LocalSessionFactoryBean sessionFactory() {
        LocalSessionFactoryBean localSessionFactoryBean = new LocalSessionFactoryBean();
        localSessionFactoryBean.setDataSource( dataSource() );
        localSessionFactoryBean.setConfigLocation( new ClassPathResource( "hibernate.cfg.xml" ) ); // the following properties are not present in this XML
        localSessionFactoryBean.setPackagesToScan( "org.example" );

        // set our properties to be discoverable by SessionFactory
        localSessionFactoryBean.getHibernateProperties().setProperty( "hibernate.connection.driver_class", dataSourceDriverClass );
        localSessionFactoryBean.getHibernateProperties().setProperty( "hibernate.connection.url", dataSourceUrl );
        localSessionFactoryBean.getHibernateProperties().setProperty( "hibernate.connection.username", dataSourceUsername );
        localSessionFactoryBean.getHibernateProperties().setProperty( "hibernate.connection.password", dataSourcePassword );
        localSessionFactoryBean.getHibernateProperties().setProperty( "hibernate.dialect", dataSourceDialect );
        if ( dataSourceDefaultSchema != null )
            localSessionFactoryBean.getHibernateProperties().setProperty( "hibernate.default_schema", dataSourceDefaultSchema );

        return localSessionFactoryBean;
    }
}

db.properties 文件的路径必须在 VM 选项中提供，如下所示：-DdbConfigPath=C:\path\to\db.properties