数据源配置

数据源配置是Spring数据访问的基础，连接池管理数据库连接。

HikariCP配置（Spring Boot默认）

# application.yml
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mydb
    username: root
    password: password
    driver-class-name: com.mysql.cj.jdbc.Driver
    hikari:
      minimum-idle: 5
      maximum-pool-size: 20
      idle-timeout: 30000
      max-lifetime: 1800000
      connection-timeout: 30000
      pool-name: MyHikariPool

@Configuration
public class HikariConfig {

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.hikari")
    public DataSource dataSource() {
        HikariDataSource ds = new HikariDataSource();
        ds.setJdbcUrl("jdbc:mysql://localhost:3306/mydb");
        ds.setUsername("root");
        ds.setPassword("password");
        ds.setMinimumIdle(5);
        ds.setMaximumPoolSize(20);
        return ds;
    }
}

Druid配置

# application.yml
spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    url: jdbc:mysql://localhost:3306/mydb
    username: root
    password: password
    druid:
      initial-size: 5
      min-idle: 5
      max-active: 20
      max-wait: 60000
      time-between-eviction-runs-millis: 60000
      min-evictable-idle-time-millis: 300000
      validation-query: SELECT 1
      test-while-idle: true
      test-on-borrow: false
      test-on-return: false
      filters: stat,wall

@Bean
public DataSource druidDataSource() {
    DruidDataSource ds = new DruidDataSource();
    ds.setUrl("jdbc:mysql://localhost:3306/mydb");
    ds.setUsername("root");
    ds.setPassword("password");
    ds.setInitialSize(5);
    ds.setMaxActive(20);
    ds.setFilters("stat,wall");
    return ds;
}

多数据源配置

@Configuration
public class MultiDataSourceConfig {

    // 主数据源
    @Bean
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource.primary")
    public DataSource primaryDataSource() {
        return DataSourceBuilder.create().build();
    }

    // 从数据源
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.secondary")
    public DataSource secondaryDataSource() {
        return DataSourceBuilder.create().build();
    }

    // 主数据源JdbcTemplate
    @Bean
    @Primary
    public JdbcTemplate primaryJdbcTemplate(
            @Qualifier("primaryDataSource") DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }

    // 从数据源JdbcTemplate
    @Bean
    public JdbcTemplate secondaryJdbcTemplate(
            @Qualifier("secondaryDataSource") DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }
}

# application.yml
spring:
  datasource:
    primary:
      url: jdbc:mysql://localhost:3306/primary_db
      username: root
      password: password
      driver-class-name: com.mysql.cj.jdbc.Driver
    secondary:
      url: jdbc:mysql://localhost:3306/secondary_db
      username: root
      password: password
      driver-class-name: com.mysql.cj.jdbc.Driver

动态数据源

// 动态数据源上下文
public class DataSourceContextHolder {
    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();

    public static void setDataSource(String dataSource) {
        contextHolder.set(dataSource);
    }

    public static String getDataSource() {
        return contextHolder.get();
    }

    public static void clearDataSource() {
        contextHolder.remove();
    }
}

// 动态路由数据源
public class DynamicRoutingDataSource extends AbstractRoutingDataSource {

    @Override
    protected Object determineCurrentLookupKey() {
        return DataSourceContextHolder.getDataSource();
    }
}

// 配置动态数据源
@Configuration
public class DynamicDataSourceConfig {

    @Bean
    public DataSource dynamicDataSource(
            @Qualifier("primaryDataSource") DataSource primary,
            @Qualifier("secondaryDataSource") DataSource secondary) {
        DynamicRoutingDataSource dynamicDataSource = new DynamicRoutingDataSource();

        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put("primary", primary);
        targetDataSources.put("secondary", secondary);

        dynamicDataSource.setTargetDataSources(targetDataSources);
        dynamicDataSource.setDefaultTargetDataSource(primary);

        return dynamicDataSource;
    }
}

// 使用注解切换数据源
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface DataSource {
    String value() default "primary";
}

// AOP切换数据源
@Aspect
@Component
public class DataSourceAspect {

    @Before("@annotation(dataSource)")
    public void switchDataSource(DataSource dataSource) {
        DataSourceContextHolder.setDataSource(dataSource.value());
    }

    @After("@annotation(dataSource)")
    public void restoreDataSource(DataSource dataSource) {
        DataSourceContextHolder.clearDataSource();
    }
}

// 使用示例
@Service
public class OrderService {

    @DataSource("primary")
    public void saveToPrimary(Order order) { }

    @DataSource("secondary")
    public void saveToSecondary(Order order) { }
}

连接池参数说明

JNDI数据源

@Configuration
public class JndiDataSourceConfig {

    @Bean
    public DataSource jndiDataSource() {
        JndiDataSourceLookup lookup = new JndiDataSourceLookup();
        return lookup.getDataSource("java:comp/env/jdbc/myDS");
    }
}

spring:
  datasource:
    jndi-name: java:comp/env/jdbc/myDS

连接池监控

// HikariCP监控
@Bean
public HikariDataSource hikariDataSource() {
    HikariDataSource ds = new HikariDataSource();
    // ... 配置
    ds.setMetricRegistry(new MetricRegistry());  // Dropwizard Metrics
    return ds;
}

// 获取连接池信息
HikariPoolMXBean pool = ds.getHikariPoolMXBean();
System.out.println("活跃连接: " + pool.getActiveConnections());
System.out.println("空闲连接: " + pool.getIdleConnections());
System.out.println("等待连接: " + pool.getThreadsAwaitingConnection());

要点总结

• Spring Boot默认使用HikariCP连接池
• Druid提供更丰富的监控和SQL防注入功能
• @Primary指定默认多数据源
• AbstractRoutingDataSource实现动态数据源切换
• ThreadLocal存储当前数据源标识
• 合理配置连接池参数优化性能