Springboot 2.3.1 dynamically update Jdbc template's schema in Multi-tenant environment

问题

My Project is on spring-boot-starter-parent - "1.5.9.RELEASE" and I'm migrating it to spring-boot-starter-parent - "2.3.1.RELEASE".

This is multi-tenant env application, where one database will have multiple schemas, and based on the tenant-id, execution switches between schemas.

I had achieved this schema switching using SimpleNativeJdbcExtractor but in the latest Springboot version NativeJdbcExtractor is no longer available.

Code snippet for the existing implementation:

 @Bean
@Scope(
        value = ConfigurableBeanFactory.SCOPE_PROTOTYPE,
        proxyMode = ScopedProxyMode.TARGET_CLASS)
public JdbcTemplate jdbcTemplate() {
    JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
    SimpleNativeJdbcExtractor simpleNativeJdbcExtractor = new SimpleNativeJdbcExtractor() {
        @Override
        public Connection getNativeConnection(Connection con) throws SQLException {
            LOGGER.debug("Set schema for getNativeConnection "+Utilities.getTenantId());
            con.setSchema(Utilities.getTenantId());
            return super.getNativeConnection(con);
        }

        @Override
        public Connection getNativeConnectionFromStatement(Statement stmt) throws SQLException {
            LOGGER.debug("Set schema for getNativeConnectionFromStatement "+Utilities.getTenantId());
            Connection nativeConnectionFromStatement = super.getNativeConnectionFromStatement(stmt);
            nativeConnectionFromStatement.setSchema(Utilities.getTenantId());
            return nativeConnectionFromStatement;
        }
    };

    simpleNativeJdbcExtractor.setNativeConnectionNecessaryForNativeStatements(true);
    simpleNativeJdbcExtractor.setNativeConnectionNecessaryForNativePreparedStatements(true);

    jdbcTemplate.setNativeJdbcExtractor(simpleNativeJdbcExtractor);
    return jdbcTemplate;
}

Here Utilities.getTenantId() ( Stored value in ThreadLocal) would give the schema name based on the REST request.

Questions:

What are the alternates to NativeJdbcExtractor so that schema can be dynamically changed for JdbcTemplate?
Is there any other way, where while creating the JdbcTemplate bean I can set the schema based on the request.

Any help, code snippet, or guidance to solve this issue is deeply appreciated.

Thanks.

回答1:

There's no need to get rid of JdbcTemplate. NativeJdbcExtractor was removed in Spring Framework 5 as it isn't needed with JDBC 4.

You should replace your usage of NativeJdbcExtractor with calls to connection.unwrap(Class). The method is inherited by Connection from JDBC's Wrapper.

You may also want to consider using AbstractRoutingDataSource which is designed to route connection requests to different underlying data sources based on a lookup key.

回答2:

When I was running the application in debug mode I saw Spring was selecting Hikari Datasource.

I had to intercept getConnection call and update schema.

So I did something like below,

Created a Custom class which extends HikariDataSource

public class CustomHikariDataSource extends HikariDataSource {
@Override
public Connection getConnection() throws SQLException {

    Connection connection =  super.getConnection();
    connection.setSchema(Utilities.getTenantId());
    return connection;
}
}

Then in the config class, I created bean for my CustomHikariDataSource class.

 @Bean
public DataSource customDataSource(DataSourceProperties properties) {

    final CustomHikariDataSource dataSource = (CustomHikariDataSource) properties
            .initializeDataSourceBuilder().type(CustomHikariDataSource.class).build();
    if (properties.getName() != null) {
        dataSource.setPoolName(properties.getName());
    }
    return dataSource;
}

Which will be used by the JdbcTemplate bean.

 @Bean
@Scope(
        value = ConfigurableBeanFactory.SCOPE_PROTOTYPE,
        proxyMode = ScopedProxyMode.TARGET_CLASS)
public JdbcTemplate jdbcTemplate() throws SQLException {
    JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
    return jdbcTemplate;
}

With this approach, I will have DataSource bean created only once and for every JdbcTemplate access, the proper schema will be updated during runtime.

来源：https://stackoverflow.com/questions/63055393/springboot-2-3-1-dynamically-update-jdbc-templates-schema-in-multi-tenant-envir

标签

java

database

spring-boot

multi-tenant

jdbctemplate