使用 Sharding-Jdbc 实现分库分表、读写分离（未完待续）

先贴代码, 回头讲解。未完待续

规划

实现分库分表、读写分离。
准备两张表：svc_order, svc_order_item

结构如下，可以想象成是未实施分库分表之前的数据库结构：

CREATE DATABASE IF NOT EXISTS DATABASE;
USE DATABASE;

CREATE TABLE IF NOT EXISTS `svc_order` (
  `order_id` bigint(64) NOT NULL AUTO_INCREMENT,
  `user_id` bigint(64) DEFAULT NULL,
  `order_name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item` (
  `order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
  `order_id` bigint(64) DEFAULT NULL,
  `order_item_name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

一定要对原有结构做到心中有数，重复表述一下：
我们原有一个数据库叫 database, 里面有两张表，分别是 svc_order 订单表和 svc_order_item 订单明细表，每个表都有一个主键ID 、用户ID(user_id) 和 名称。

计划：
svc_order 表按照 user_id 分库，按照主键 order_id 分片
svc_order_item 表按照 user_id 分库，按照主键 order_item_id 分片

原有库分成两个库，使用 user_id 对 2 取模，例如 user_id = 2 的存入 0 库，user_id = 3 的存入 1 库。
原有表分成两个表，svc_order 订单表使用 order_id 对 2 取模，svc_order_item 表使用 order_item_id 对 2 取模，例如 order_id = 2 的存入 0 表，order_id = 3 的存入 1 表。

读写分离设置为 1 个写库，2 个读库。

为了便于理解，我们定义常用名词：

• 逻辑表：指的就是未实施分表之前的表名。例如 svc_order 就是逻辑表名。

• 虚拟表、物理表：指的是分表后真实存在的表名。上面我们说到存到 0 表、 1 表就是虚拟表，为了便于理解，我们把逻辑表名加在前面，比如 svc_order 的两个虚表我们可以命名为 svc_order_0、svc_order_1

顺便说明一下数据库名，我们原有 database, 由于要分成两个库，我们可以命名为 database_0、database_1，由于，需要读写分离（1带2），相当于又多了四个数据库，至此，我们的数据库应该有 write_database_0,read_0_database_0,read_1_database_0,write_database_1,read_0_database_1,read_1_database_1

数据库

init.sql

DROP DATABASE IF EXISTS write_database_0;
DROP DATABASE IF EXISTS read_0_database_0;
DROP DATABASE IF EXISTS read_1_database_0;
DROP DATABASE IF EXISTS write_database_1;
DROP DATABASE IF EXISTS read_0_database_1;
DROP DATABASE IF EXISTS read_1_database_1;

CREATE DATABASE IF NOT EXISTS write_database_0;
USE write_database_0;

CREATE TABLE IF NOT EXISTS `svc_order_0` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_1` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_0` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_1` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE DATABASE IF NOT EXISTS read_1_database_0;
USE read_1_database_0;

CREATE TABLE IF NOT EXISTS `svc_order_0` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_1` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_0` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_1` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE DATABASE IF NOT EXISTS read_0_database_0;
USE read_0_database_0;

CREATE TABLE IF NOT EXISTS `svc_order_0` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_1` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_0` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_1` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE DATABASE IF NOT EXISTS write_database_1;
USE write_database_1;

CREATE TABLE IF NOT EXISTS `svc_order_0` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_1` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_0` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_1` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE DATABASE IF NOT EXISTS read_0_database_1;
USE read_0_database_1;

CREATE TABLE IF NOT EXISTS `svc_order_0` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_1` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_0` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_1` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE DATABASE IF NOT EXISTS read_1_database_1;
USE read_1_database_1;

CREATE TABLE IF NOT EXISTS `svc_order_0` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_1` (
`order_id` bigint(64) NOT NULL AUTO_INCREMENT,
`user_id` bigint(64) DEFAULT NULL,
`order_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_0` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS  `svc_order_item_1` (
`order_item_id` bigint(64) NOT NULL AUTO_INCREMENT,
`order_id` bigint(64) DEFAULT NULL,
`order_item_name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`order_item_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

依赖

pom.xml

    com.alibaba
    druid
    1.1.5


    mysql
    mysql-connector-java
    6.0.6


    com.dangdang
    sharding-jdbc-core
    1.5.4.1


    org.projectlombok
    lombok
    1.16.18
    provided

配置

ShardingJdbcConfig.java

package com.junbaor.sharding.config;

import com.alibaba.druid.pool.DruidDataSource;
import com.dangdang.ddframe.rdb.sharding.api.MasterSlaveDataSourceFactory;
import com.dangdang.ddframe.rdb.sharding.api.ShardingDataSourceFactory;
import com.dangdang.ddframe.rdb.sharding.api.rule.BindingTableRule;
import com.dangdang.ddframe.rdb.sharding.api.rule.DataSourceRule;
import com.dangdang.ddframe.rdb.sharding.api.rule.ShardingRule;
import com.dangdang.ddframe.rdb.sharding.api.rule.TableRule;
import com.dangdang.ddframe.rdb.sharding.api.strategy.database.DatabaseShardingStrategy;
import com.dangdang.ddframe.rdb.sharding.api.strategy.slave.MasterSlaveLoadBalanceStrategyType;
import com.dangdang.ddframe.rdb.sharding.api.strategy.table.TableShardingStrategy;
import com.dangdang.ddframe.rdb.sharding.config.ShardingPropertiesConstant;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;


@Configuration
public class ShardingJdbcConfig {

    @Bean
    public DataSource buildDataSource() throws SQLException {
        /*读写分离 start */
        DataSource writeDatabase0 = createDataSource("write_database_0");
        Map slave0DataBase = new HashMap<>(2);
        slave0DataBase.put("read0_database_0", createDataSource("read0_database_0"));
        slave0DataBase.put("read1_database_0", createDataSource("read1_database_0"));
        DataSource database0 = MasterSlaveDataSourceFactory.createDataSource("write_database_0", "write_database_0", writeDatabase0, slave0DataBase, MasterSlaveLoadBalanceStrategyType.ROUND_ROBIN);

        DataSource writeDatabase1 = createDataSource("write_database_1");
        Map slave1DataBase = new HashMap<>(2);
        slave1DataBase.put("read0_database_1", createDataSource("read0_database_1"));
        slave1DataBase.put("read1_database_1", createDataSource("read1_database_1"));
        DataSource database1 = MasterSlaveDataSourceFactory.createDataSource("write_database_1", "write_database_1", writeDatabase1, slave1DataBase, MasterSlaveLoadBalanceStrategyType.ROUND_ROBIN);
        /*读写分离 end */

        Map dataSourceMap = new HashMap<>(2);
        dataSourceMap.put("database_0", database0);
        dataSourceMap.put("database_1", database1);

        /*分库分表 start*/
        DataSourceRule dataSourceRule = new DataSourceRule(dataSourceMap, "database_0");

        TableRule orderTableRule = TableRule.builder("svc_order")
                .actualTables(Arrays.asList("svc_order_0", "svc_order_1"))
                .generateKeyColumn("order_id", KeyGenerate.class)
                .dataSourceRule(dataSourceRule)
                .build();

        TableRule orderItemTableRule = TableRule.builder("svc_order_item")
                .actualTables(Arrays.asList("svc_order_item_0", "svc_order_item_1"))
                .generateKeyColumn("order_item_id",KeyGenerate.class)
                .dataSourceRule(dataSourceRule)
                .build();

        BindingTableRule bindOrderAndOrderItem = new BindingTableRule(Arrays.asList(orderTableRule, orderItemTableRule));

        ShardingRule shardingRule = ShardingRule.builder()
                .dataSourceRule(dataSourceRule)
                .tableRules(Arrays.asList(orderTableRule, orderItemTableRule))
                .databaseShardingStrategy(new DatabaseShardingStrategy(Arrays.asList("user_id"), new DbSharding()))
                .tableShardingStrategy(new TableShardingStrategy(Arrays.asList("order_id"), new TableSharding()))
                .bindingTableRules(Arrays.asList(bindOrderAndOrderItem))
                .build();
        /*分库分表 end*/

        Properties properties = new Properties();
        properties.setProperty(ShardingPropertiesConstant.SQL_SHOW.getKey(), "true");
        DataSource dataSource = ShardingDataSourceFactory.createDataSource(shardingRule, properties);

        return dataSource;
    }

    private static DataSource createDataSource(final String dataSourceName) {
        DruidDataSource result = new DruidDataSource();
        result.setUrl(String.format("jdbc:mysql://127.0.0.1:3306/%s?useUnicode=true&characterEncoding=utf-8&useSSL=false", dataSourceName));
        result.setUsername("root");
        result.setPassword("root");
        return result;
    }

}

分片工具

AppUtils.java

package com.junbaor.sharding.util;

import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;

import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;

public class AppUtils {

    public static Collection sharding(Collection availableTargetNames, Collection> shardingValues) {
        long shardingvalue = 0;

        Iterator> iterator = shardingValues.iterator();
        if (iterator.hasNext()) {
            shardingvalue = ((Long) iterator.next().getValue()).intValue();
        }

        for (String tableName : availableTargetNames) {
            if (tableName.endsWith((shardingvalue % 2) + "")) {
                return Arrays.asList(tableName);
            }
        }
        return null;
    }
}

分库算法

DbSharding.java

package com.junbaor.sharding.config;

import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.database.MultipleKeysDatabaseShardingAlgorithm;
import com.junbaor.sharding.util.AppUtils;

import java.util.Collection;

/**
 * 利用多分片键接口实现单键分片算法
 */
public class DbSharding implements MultipleKeysDatabaseShardingAlgorithm {

    @Override
    public Collection doSharding(Collection availableTargetNames, Collection> shardingValues) {
        Collection sharding = AppUtils.sharding(availableTargetNames, shardingValues);
        if (sharding != null) {
            return sharding;
        }
        return null;
    }
}

分表算法

TableSharding.java

package com.junbaor.sharding.config;

import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.table.MultipleKeysTableShardingAlgorithm;
import com.junbaor.sharding.util.AppUtils;

import java.util.Collection;

/**
 * 利用多分片键接口实现单键分片算法
 */
public class TableSharding implements MultipleKeysTableShardingAlgorithm {

    @Override
    public Collection doSharding(Collection availableTargetNames, Collection> shardingValues) {
        Collection sharding = AppUtils.sharding(availableTargetNames, shardingValues);
        if (sharding != null) {
            return sharding;
        }
        return null;
    }

}

主键生成器

KeyGenerate.java 仅供单机测试

package com.junbaor.sharding.config;

import com.dangdang.ddframe.rdb.sharding.keygen.KeyGenerator;
import lombok.extern.slf4j.Slf4j;

import java.util.concurrent.atomic.AtomicLong;

@Slf4j
public class KeyGenerate implements KeyGenerator {
    
    private static AtomicLong atomicInteger = new AtomicLong(1);

    @Override
    public Number generateKey() {
        long nextId = atomicInteger.addAndGet(1);
        log.info("nextId:{}", nextId);
        return nextId;
    }
}