Druid 分表分库 使用实例

下面给出一个使用Druid连接池实现分表分库的示例：

1. 添加Druid连接池依赖，例如在Maven项目中添加以下依赖：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.2.3</version>
</dependency>

2. 配置Druid连接池，例如在Spring Boot项目中可以在application.properties文件中添加以下配置：

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/testdb?useUnicode=true&characterEncoding=utf8&autoReconnect=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.initialSize=5
spring.datasource.minIdle=5
spring.datasource.maxActive=20
spring.datasource.maxWait=60000
spring.datasource.validationQuery=SELECT 1 FROM DUAL
spring.datasource.testOnBorrow=false
spring.datasource.testOnReturn=false
spring.datasource.testWhileIdle=true
spring.datasource.timeBetweenEvictionRunsMillis=60000
spring.datasource.minEvictableIdleTimeMillis=25200000
spring.datasource.filters=stat,wall,log4j
spring.datasource.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000

其中，spring.datasource.url中的testdb是数据库名，可以根据实际情况修改为自己的数据库名。

3. 实现分表分库功能，例如可以在代码中使用Sharding-JDBC来实现分表分库功能，具体实现方式可以参考以下示例：

@Configuration
public class DataSourceConfiguration {

    @Bean
    public DataSource dataSource() throws SQLException {
        Map<String, DataSource> dataSourceMap = new HashMap<>();
        dataSourceMap.put("ds0", createDataSource("ds0"));
        dataSourceMap.put("ds1", createDataSource("ds1"));

        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTableRuleConfigs().add(getOrderTableRuleConfiguration());
        shardingRuleConfig.getBindingTableGroups().add("t_order");

        return ShardingDataSourceFactory.createDataSource(dataSourceMap, shardingRuleConfig, new Properties());
    }

    private TableRuleConfiguration getOrderTableRuleConfiguration() {
        TableRuleConfiguration result = new TableRuleConfiguration("t_order", "ds${0..1}.t_order_${0..1}");
        result.setDatabaseShardingStrategyConfig(new InlineShardingStrategyConfiguration("user_id", "ds${user_id % 2}"));
        result.setTableShardingStrategyConfig(new InlineShardingStrategyConfiguration("order_id", "t_order_${order_id % 2}"));
        return result;
    }

    private DataSource createDataSource(final String dataSourceName) throws SQLException {
        DruidDataSource result = new DruidDataSource();
        result.setDriverClassName("com.mysql.jdbc.Driver");
        result.setUrl(String.format("jdbc:mysql://localhost:3306/%s?useUnicode=true&characterEncoding=utf8&useSSL=false", dataSourceName));
        result.setUsername("root");
        result.setPassword("root");
        return result;
    }
}

以上示例中，创建了两个数据源ds0和ds1，分别对应了两个数据库，使用Sharding-JDBC实现了分表分库功能，其中按照user_id对数据进行分库，按照order_id对表进行分表。