Spring-数据源

单数据源

showConnection()方法可以显示当前的数据源的信息

@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()));
	}
}

localhost:8080/actuator/beans
可以看都配置了哪些bean

SpringBoot做了哪些配置

DataSourceAutoConfiguration

• 配置DataSource

DataSourceTransactionManagerAutoConfiguration

• 配置DataSourceTransactionManager

JdbcTemplateAutoConfiguration

• 配置JdbcTemplate

符合条件时才进行配置

不用SpringBoot，jdbc的配置

@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();
    }
}

或使用配置文件的方式配置，两者是等同的：
/resource/applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="geektime.spring.data" />
    <!--
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
          destroy-method="close">
        <property name="driverClassName" value="org.h2.Driver"/>
        <property name="url" value="jdbc:h2:mem:testdb"/>
        <property name="username" value="SA"/>
        <property name="password" value=""/>
    </bean>
    -->
</beans>

数据源相关配置属性

通用

• spring.datasource.url=jdbc:mysql://localhost/test
• spring.datasource.username=dbuser
• spring.datasource.password=dbpass
• spring.datasource.driver-class-name=com.mysql.jdbc.Driver(可选)（不写的话spring会根据url自动判断）

初始化内嵌数据库（h2）

• spring.datasource.initialization-mode=embedded|always|never
• spring.datasource.schema与spring.datasource.data确定初始化sql文件
• spring.datasource.platform=hsqldb|h2|oracle|mysql|postgresql(与前者对应)