如何实现分库分表？怎么配置？

朴灿烈づ我的快乐病毒、 2022-12-10 08:39 121阅读 0赞

**分库分表的实现方案，一般分为两种**

1、增加一个中间层，中间层实现 MySQL 客户端协议，可以做到应用程序无感知地与中间层交互。由于是基于协议层的代理，可以做到支持多语言，但需要多启动一个进程、SQL 的解析也耗费大量性能、由于协议绑定仅支持单个种类的数据库库。

2、在代码层面增加一个路由程序，控制对数据库与表的读写。路由程序写在项目里，与编程语言绑定、连接数高、但相对轻量（比如 Java 仅需要引入 SharingShpere 组件中 Sharding-JDBC 的 jar 即可）、支持任意数据库。

**代码怎么写？怎么配？**

以 Sharding-JDBC 实现分库分表为例子

**1、数据库环境**  
ds0：172.31.32.184  
ds1：172.31.32.234  
用作分库

**2、在 ds0 和 ds1 库中建表，t\_order0 和 t\_order1 用做分表**

create table t_order0(
    order_id int primary key,
    user_id int, 
    goods_id int,
    goods_name varchar(200)
    );
    
    create table t_order1(
    order_id int primary key,
    user_id int, 
    goods_id int,
    goods_name varchar(200)
    );

**3、新建 maven 项目，添加依赖**

<dependency>
        <groupId>org.apache.shardingsphere</groupId>
        <artifactId>sharding-jdbc-core</artifactId>
        <version>4.1.1</version>
    </dependency>
    
    <dependency>
        <groupId>com.zaxxer</groupId>
        <artifactId>HikariCP</artifactId>
        <version>3.4.5</version>
    </dependency>
    
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.21</version>
    </dependency>

**4、数据源连接工具类，使用 HikariCP 数据库连接池**

package constxiong;
    
    import com.zaxxer.hikari.HikariDataSource;
    
    /**
     * 获取 DataSource 工具类，使用了 Hikari 数据库连接池
     */
    import javax.sql.DataSource;
    
    public final class DataSourceUtil {
    
        private static final int PORT = 3306;
    
        /**
         * 通过 Hikari 数据库连接池创建 DataSource
         * @param ip
         * @param username
         * @param password
         * @param dataSourceName
         * @return
         */
        public static DataSource createDataSource(String ip, String username, String password, String dataSourceName) {
            HikariDataSource result = new HikariDataSource();
            result.setDriverClassName(com.mysql.jdbc.Driver.class.getName());
            result.setJdbcUrl(String.format("jdbc:mysql://%s:%s/%s?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=UTF-8", ip, PORT, dataSourceName));
            result.setUsername(username);
            result.setPassword(password);
            return result;
        }
    }

**5、测试代码**

测试逻辑：

*  使用数据源工具类，新建 ds0 和 ds1 库的数据源
 *  配置 t\_order 表的规则，ds$->\{0..1\}.t\_order$->\{0..1\}
 *  配置分库分表的规则，分库根据 ds  拼接上 t\_order 的 user\_id 字段值 对 2 取模的值（ds$\{user\_id % 2\}）；分表根据 t\_order  拼接上 order\_id 字段值 对 2 取模的值（t\_order$\{order\_id % 2\}）
 *  测试 insert 不同的 user\_id 和 order\_id 是否会按规则插入不同的库和表
 *  查询 user\_id = 2 的数据，看看是否正常查出

package constxiong;
    
    import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
    import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
    import org.apache.shardingsphere.api.config.sharding.strategy.InlineShardingStrategyConfiguration;
    import org.apache.shardingsphere.shardingjdbc.api.ShardingDataSourceFactory;
    
    import javax.sql.DataSource;
    import java.sql.Connection;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.Properties;
    
    /**
     * 测试 ShardingSphere 分表分库
     */
    public class Test {
    
        //DataSource 0
        private static DataSource ds0 = DataSourceUtil.createDataSource("172.31.32.234", "root", "constxiong@123", "constxiong");
        // DataSource 1
        private static DataSource ds1 = DataSourceUtil.createDataSource("172.31.32.184", "root", "constxiong@123", "constxiong");
    
        public static void main(String[] args) throws SQLException {
            // 配置真实数据源
            Map<String, DataSource> dataSourceMap = new HashMap<>();
            dataSourceMap.put("ds0", ds0);
            dataSourceMap.put("ds1", ds1);
    
            // 配置Order表规则
            TableRuleConfiguration orderTableRuleConfig = new TableRuleConfiguration("t_order", "ds$->{0..1}.t_order$->{0..1}");
    
            // 配置分库 + 分表策略
            orderTableRuleConfig.setDatabaseShardingStrategyConfig(new InlineShardingStrategyConfiguration("user_id", "ds${user_id % 2}"));
            orderTableRuleConfig.setTableShardingStrategyConfig(new InlineShardingStrategyConfiguration("order_id", "t_order${order_id % 2}"));
    
            // 配置分片规则
            ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
            shardingRuleConfig.getTableRuleConfigs().add(orderTableRuleConfig);
    
            // 获取数据源对象
            DataSource dataSource = ShardingDataSourceFactory.createDataSource(dataSourceMap, shardingRuleConfig, new Properties());
            Connection connection = dataSource.getConnection();
            Statement statement = connection.createStatement();
            statement.execute("insert into t_order value(1, 1, 1, '电视机')");
            statement.execute("insert into t_order value(2, 1, 2, '可乐')");
            statement.execute("insert into t_order value(3, 2, 8, '空调')");
            statement.execute("insert into t_order value(4, 2, 9, '手机壳')");
    
            statement.execute("select * from t_order where user_id = 2");
            ResultSet resultSet = statement.getResultSet();
            while (resultSet.next()) {
                System.out.printf("user_id:%d, order_id:%d, goods_id:%d, goods_name:%s\n",
                        resultSet.getInt("user_id"),
                        resultSet.getInt("order_id"),
                        resultSet.getInt("goods_id"),
                        resultSet.getString("goods_name")
                );
            }
        }
    }

**6、结果**

数据按照分库分表的规则插入对应的数据库与表中

![6433c83e453901e508781e5b93605c85.png][]

user\_id = 2 数据代码查询

user_id:2, order_id:4, goods_id:9, goods_name:手机壳
    user_id:2, order_id:3, goods_id:8, goods_name:空调

--------------------

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