配置数据源

如何配置单数据源

搭建项目

主要相关的依赖是H2 和 JDBC, 如果是别的数据库就选别的，入Mysql

查看datasource是否配置成功

@SpringBootApplication
@Slf4j
public class DataSourceDemoApplication implements CommandLineRunner {
	@Autowired
	private DataSource dataSource;

	@Autowired
	private JdbcTemplate jdbcTemplate;

	public static void main(String[] args) {
		SpringApplication.run(DataSourceDemoApplication.class, args);
	}

	@Override
	public void run(String... args) throws Exception {
		showConnection();
		showData();
	}

	private void showConnection() throws SQLException {
		log.info(dataSource.toString());
		Connection conn = dataSource.getConnection();
		log.info(conn.toString());
		conn.close();
	}

	private void showData() {
		jdbcTemplate.queryForList("SELECT * FROM FOO")
				.forEach(row -> log.info(row.toString()));
	}
}

启动程序控制台输出：

说明spingboot自动帮我们配置好了dataSource和jdbcTemplate.

当然也可以在配置文件中改变数据源的一些连接信息：

spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.username=sa
spring.datasource.password=
spring.datasource.hikari.maximumPoolSize=5
spring.datasource.hikari.minimumIdle=5
spring.datasource.hikari.idleTimeout=600000
spring.datasource.hikari.connectionTimeout=30000
spring.datasource.hikari.maxLifetime=1800000

CommandLineRunner解释：在spirngboot启动完成后会执行它的run方法。

如果不是springboot项目，而是spring项目我们需要怎么配置呢？

我们需要手动地配置dataSource,transactionManager以及JdbcTemplate这些bean.

@Configuration
@EnableTransactionManagement
public class DataSourceDemo {
    @Autowired
    private DataSource dataSource;

    public static void main(String[] args) throws SQLException {
        ApplicationContext applicationContext =
                new ClassPathXmlApplicationContext("applicationContext*.xml");
        showBeans(applicationContext);
        dataSourceDemo(applicationContext);
    }

    @Bean(destroyMethod = "close")
    public DataSource dataSource() throws Exception {
        Properties properties = new Properties();
        properties.setProperty("driverClassName", "org.h2.Driver");
        properties.setProperty("url", "jdbc:h2:mem:testdb");
        properties.setProperty("username", "sa");
        return BasicDataSourceFactory.createDataSource(properties);
    }

    @Bean
    public PlatformTransactionManager transactionManager() throws Exception {
        return new DataSourceTransactionManager(dataSource());
    }

    private static void showBeans(ApplicationContext applicationContext) {
        System.out.println(Arrays.toString(applicationContext.getBeanDefinitionNames()));
    }

    private static void dataSourceDemo(ApplicationContext applicationContext) throws SQLException {
        DataSourceDemo demo = applicationContext.getBean("dataSourceDemo", DataSourceDemo.class);
        demo.showDataSource();
    }

    public void showDataSource() throws SQLException {
        System.out.println(dataSource.toString());
        Connection conn = dataSource.getConnection();
        System.out.println(conn.toString());
        conn.close();
    }
}

所以可以看得出springboot帮我们做了很多的配置bean的工作，如果我们没有配置，它会帮我们配置，如果我们自己配置了，那就不会自动配置了

如何配置多数据源

配置多数据源的注意事项

　　不同数据源的配置要分开
　　关注每次使⽤用的数据源

　　　　• 有多个DataSource时系统如何判断
　　　　• 对应的设施（事务、ORM等）如何选择DataSource

Spring Boot中的多数据源配置

　　⼿手⼯工配置两组 DataSource 及相关内容
　　与Spring Boot协同⼯工作（⼆选一）

　　　　• 配置@Primary类型的Bean
　　　　• 排除Spring Boot的⾃自动配置
　　　　　　• DataSourceAutoConfiguration
　　　　　　• DataSourceTransactionManagerAutoConfiguration
　　　　　　• JdbcTemplateAutoConfiguration

package geektime.spring.data.multidatasourcedemo;

import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

import javax.annotation.Resource;
import javax.sql.DataSource;

@SpringBootApplication(exclude = { DataSourceAutoConfiguration.class,
        DataSourceTransactionManagerAutoConfiguration.class,
        JdbcTemplateAutoConfiguration.class})
@Slf4j
public class MultiDataSourceDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(MultiDataSourceDemoApplication.class, args);
    }

    @Bean
    @ConfigurationProperties("foo.datasource")
    public DataSourceProperties fooDataSourceProperties() {
        return new DataSourceProperties();
    }

    @Bean
    public DataSource fooDataSource() {
        DataSourceProperties dataSourceProperties = fooDataSourceProperties();
        log.info("foo datasource: {}", dataSourceProperties.getUrl());
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }

    @Bean
    @Resource
    public PlatformTransactionManager fooTxManager(DataSource fooDataSource) {
        return new DataSourceTransactionManager(fooDataSource);
    }

    @Bean
    @ConfigurationProperties("bar.datasource")
    public DataSourceProperties barDataSourceProperties() {
        return new DataSourceProperties();
    }

    @Bean
    public DataSource barDataSource() {
        DataSourceProperties dataSourceProperties = barDataSourceProperties();
        log.info("bar datasource: {}", dataSourceProperties.getUrl());
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }

    @Bean
    @Resource
    public PlatformTransactionManager barTxManager(DataSource barDataSource) {
        return new DataSourceTransactionManager(barDataSource);
    }
}