SpringBoot 应用程序。使用 JdbcTemplate 访问 2 个数据源

Question

我有一个 SpringBoot 应用程序。必须访问不同的数据源才能将数据从 1 导出到另一个(1 个本地数据源和另一个远程数据源)

这就是我的 persistenceConfig 的样子

public class PersistenceConfig {

    @Bean
    public  JdbcTemplate localJdbcTemplate() {
        return new JdbcTemplate(localDataSource());
    }

    @Bean
    public  JdbcTemplate remoteJdbcTemplate() {
        return new JdbcTemplate(remoteDataSource());
    }



    @Bean
    public DataSource localDataSource(){

        HikariConfig config = new HikariConfig();
        config.setMaximumPoolSize(getLocalDbPoolSize());
        config.setMinimumIdle(5);
        config.setDriverClassName(getLocalDbDriverClassName());
        config.setJdbcUrl(getLocalDbJdbcUrl());
        config.addDataSourceProperty("user", getLocalDbUser());
        config.addDataSourceProperty("password", getLocalDbPwd());

        return new HikariDataSource(config);
    }


    @Bean
    public DataSource remoteDataSource(){

        HikariConfig config = new HikariConfig();
        config.setMaximumPoolSize(getRemoteDbPoolSize());
        config.setMinimumIdle(5);
        config.setDriverClassName(getRemoteDbDriverClassName());
        config.setJdbcUrl(getRemoteDbJdbcUrl());
        config.addDataSourceProperty("user", getRemoteDbUser());
        config.addDataSourceProperty("password", getRemoteDbPwd());

        return new HikariDataSource(config);
    }
}

但是当我启动我的应用程序时，我收到此错误:

Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'javax.sql.DataSource' available: expected single matching bean but found 2: localDataSource,remoteDataSource

我还尝试使用合格的bean，如下所示:

@Bean(name = "localJdbcTemplate")
    public  JdbcTemplate localJdbcTemplate() {
        return new JdbcTemplate(localDataSource());
    }


    @Bean(name = "remoteJdbcTemplate")
    public  JdbcTemplate remoteJdbcTemplate() {
        return new JdbcTemplate(remoteDataSource());
    }



    @Bean(name = "localDataSource")
    public DataSource localDataSource(){

        HikariConfig config = new HikariConfig();
        config.setMaximumPoolSize(getLocalDbPoolSize());
        config.setMinimumIdle(5);
        config.setDriverClassName(getLocalDbDriverClassName());
        config.setJdbcUrl(getLocalDbJdbcUrl());
        config.addDataSourceProperty("user", getLocalDbUser());
        config.addDataSourceProperty("password", getLocalDbPwd());

        return new HikariDataSource(config);
    }


    @Bean(name = "remoteDataSource")
    public DataSource remoteDataSource(){

        HikariConfig config = new HikariConfig();
        config.setMaximumPoolSize(getRemoteDbPoolSize());
        config.setMinimumIdle(5);
        config.setDriverClassName(getRemoteDbDriverClassName());
        config.setJdbcUrl(getRemoteDbJdbcUrl());
        config.addDataSourceProperty("user", getRemoteDbUser());
        config.addDataSourceProperty("password", getRemoteDbPwd());

        return new HikariDataSource(config);
    }

但后来我得到了另一个错误:

A component required a bean of type 'org.springframework.transaction.PlatformTransactionManager' that could not be found.
    - Bean method 'transactionManager' not loaded because @ConditionalOnSingleCandidate (types: javax.sql.DataSource; SearchStrategy: all) did not find a primary bean from beans 'remoteDataSource', 'localDataSource'

我也尝试过

@SpringBootApplication(exclude = {
            DataSourceAutoConfiguration.class, 
            DataSourceTransactionManagerAutoConfiguration.class})
    @EnableAutoConfiguration(exclude = {
            DataSourceAutoConfiguration.class, 
            DataSourceTransactionManagerAutoConfiguration.class})

但是后来我得到了

A component required a bean of type 'org.springframework.transaction.PlatformTransactionManager' that could not be found.

Answer 1

您可以使用 bean 名称来限定它们:

@Bean(name = "localDataSource")
public DataSource localDataSource() {
  ...
}

@Bean(name = "remoteDataSource")
public DataSource remoteDataSource() {
  ...
}

请注意:您必须对 JdbcTemplate beans 执行相同的操作 - 只需给它们一个名称，它就会起作用。有关更多信息，请参阅 Spring JavaDoc:Bean

@Bean(name = "localJdbcTemplate")
public JdbcTemplate localJdbcTemplate() {
  return new JdbcTemplate(localDataSource());
}

当您通过 Autowiring (@Autowired) 在导出服务实现中使用 JdbcTemplate bean 时，您需要使用 @Qualifier 来限定它们:

@Autowired
@Qualifier("localJdbcTemplate")
private JdbcTemplate jdbcTemplate;

@Autowired
@Qualifier("remoteJdbcTemplate")
private JdbcTemplate jdbcTemplate;