如何在Spring Boot Jdbc中为MySQL数据库指定特定的默认架构

Question

我们正在从Spring Boot连接到多个数据库。

application.properties：

datasource.target.url=jdbc:mysql://localhost:3306/db_test_1?useSSL=false
datasource.target.driver-class-name=com.mysql.jdbc.Driver

datasource.origin.url=jdbc:mysql://localhost:3306/db_test_2?useSSL=false
datasource.origin.driver-class-name=com.mysql.jdbc.Driver

数据库配置：

@Configuration
public class DatabaseConfig {

    @Bean(name = "originJdbcTemplate")
    public JdbcTemplate originJdbcTemplate() {
        return new JdbcTemplate(originDataSource());
    }

    @Bean(name = "targetJdbcTemplate")
    public JdbcTemplate targetJdbcTemplate() {
        return new JdbcTemplate(targetDataSource());
    }

    @Bean
    @Primary
    @ConfigurationProperties("datasource.origin")
    public DataSourceProperties originDataSourceProperties() {
        return new DataSourceProperties();
    }

    @Bean
    @Primary
    @ConfigurationProperties("datasource.origin")
    public DataSource originDataSource() {
        return originDataSourceProperties().initializeDataSourceBuilder().build();
    }

    @Bean
    @ConfigurationProperties("datasource.target")
    public DataSourceProperties targetDataSourceProperties() {
        return new DataSourceProperties();
    }

    @Bean
    @ConfigurationProperties("datasource.target")
    public DataSource targetDataSource() {
        return targetDataSourceProperties().initializeDataSourceBuilder().build();
    }

}

我们正在使用Spring Jdbc模板，即使我们已在应用程序属性中的url中定义了架构名称，我们也必须在每个查询中显式命名架构。 例如：没有架构名称的查询不起作用

select * from db_test_1.user //works with schema name
select * from user //doesn't work

按照这个答案，我应该使用Connection.setCatalog() ，如何在Spring配置中使用它？

Answer 1

通过使用委托数据源

class DefaultSchemaDelegatingDS extends DelegatingDataSource {
    private final String catalogName;

    public DefaultSchemaDelegatingDS(final String catalogName, final DataSource dataSource) {
        super(dataSource);
        this.catalogName = catalogName;
    }

    @Override
    public Connection getConnection() throws SQLException {
        final Connection connection = super.getConnection();
        connection.setCatalog(this.catalogName);
        return connection;
    }
}

然后在DatabaseConfig中

@Configuration
public class DatabaseConfig {

    @Value("${datasource.target.default_schema}")
    private String defaultTargetSchema;

    @Value("${datasource.origin.default_schema}")
    private String defaultOriginSchema;

    @Bean(name = "originJdbcTemplate")
    public JdbcTemplate originJdbcTemplate() {
        return new JdbcTemplate(originDataSource());
    }

    @Bean(name = "targetJdbcTemplate")
    public JdbcTemplate targetJdbcTemplate() {
        return new JdbcTemplate(targetDataSource());
    }

    @Bean
    @Primary
    @ConfigurationProperties("datasource.origin")
    public DataSourceProperties originDataSourceProperties() {
        return new DataSourceProperties();
    }

    @Bean
    @Primary
    @ConfigurationProperties("datasource.origin")
    public DataSource originDataSource() {
        final DataSource ds = originDataSourceProperties().initializeDataSourceBuilder().build();
        return new DefaultSchemaDelegatingDS(defaultOriginSchema, ds);
    }

    @Bean
    @ConfigurationProperties("datasource.target")
    public DataSourceProperties targetDataSourceProperties() {
        return new DataSourceProperties();
    }

    @Bean
    @ConfigurationProperties("datasource.target")
    public DataSource targetDataSource() {
        final DataSource ds = targetDataSourceProperties().initializeDataSourceBuilder().build();
        return new DefaultSchemaDelegatingDS(defaultTargetSchema, ds);
    }
}

不使用DelegatingDatasource的另一种方法是简单地添加

jdbcTemplate.getDataSource().getConnection().setCatalog(catalogName);

例如，

@Bean(name = "originJdbcTemplate")
public JdbcTemplate originJdbcTemplate() throws SQLException {
    JdbcTemplate jdbcTemplate = new JdbcTemplate(originDataSource());
    jdbcTemplate.getDataSource().getConnection().setCatalog(defaultOriginSchema);
    return jdbcTemplate;
}