SpringBoot使用Sharding-JDBC分库分表

关于Sharding-JDBC

ShardingSphere是一套开源的分布式数据库中间件解决方案组成的生态圈，它由Sharding-JDBC、Sharding-Proxy和Sharding-Sidecar这3款相互独立的产品组成。他们均提供标准化的数据分片、分布式事务和数据库治理功能，可适用于如Java同构、异构语言、云原生等各种多样化的应用场景。

ShardingSphere定位为关系型数据库中间件，旨在充分合理地在分布式的场景下利用关系型数据库的计算和存储能力，而并非实现一个全新的关系型数据库。它与NoSQL和NewSQL是并存而非互斥的关系。NoSQL和NewSQL作为新技术探索的前沿，放眼未来，拥抱变化，是非常值得推荐的。反之，也可以用另一种思路看待问题，放眼未来，关注不变的东西，进而抓住事物本质。关系型数据库当今依然占有巨大市场，是各个公司核心业务的基石，未来也难于撼动，我们目前阶段更加关注在原有基础上的增量，而非颠覆。

本文场景

数据库

接下来介绍一下本文的场景，本文是分别创建了2个数据库database0和database1。其中每个数据库都创建了2个数据表，goods_0和goods_1，如图所示。这里蓝色的代表database0中的表，红色的代表database1中的表。绿色goods表是虚拟表（图画的比较丑，审美不好，凑合看吧）。

分库

根据数据库表中字段goods_id的大小进行判断，如果goods_id大于20则使用database0，否则使用database1。

分表

根据数据库表中字段goods_type的数值的奇偶进行判断，奇数使用goods_1表，偶数使用goods_0表。

代码流程

在应用程序中我们操作虚拟表goods，但是当真正操作数据库的时候，会根据我们的分库分表规则进行匹配然后操作。

代码实现

本文使用SpringBoot2.0.3，SpringData-JPA，Druid连接池，和当当的sharding-jdbc。

建表SQL

创建表和数据库的SQL如下所示:

CREATE DATABASE database0;
USE database0;
DROP TABLE IF EXISTS `goods_0`;
CREATE TABLE `goods_0` (
  `goods_id` bigint(20) NOT NULL,
  `goods_name` varchar(100) COLLATE utf8_bin NOT NULL,
  `goods_type` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`goods_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
DROP TABLE IF EXISTS `goods_1`;
CREATE TABLE `goods_1` (
  `goods_id` bigint(20) NOT NULL,
  `goods_name` varchar(100) COLLATE utf8_bin NOT NULL,
  `goods_type` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`goods_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
CREATE DATABASE database1;
USE database1;
DROP TABLE IF EXISTS `goods_0`;
CREATE TABLE `goods_0` (
  `goods_id` bigint(20) NOT NULL,
  `goods_name` varchar(100) COLLATE utf8_bin NOT NULL,
  `goods_type` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`goods_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

DROP TABLE IF EXISTS `goods_1`;
CREATE TABLE `goods_1` (
  `goods_id` bigint(20) NOT NULL,
  `goods_name` varchar(100) COLLATE utf8_bin NOT NULL,
  `goods_type` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`goods_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

依赖文件

新建项目，加入当当的sharding-jdbc-core依赖和druid连接池，完整pom如下所示:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.dalaoyang</groupId>
    <artifactId>springboot2_shardingjdbc_fkfb</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot2_shardingjdbc_fkfb</name>
    <description>springboot2_shardingjdbc_fkfb</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!-- druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.9</version>
        </dependency>
        <!-- sharding-jdbc -->
        <dependency>
            <groupId>com.dangdang</groupId>
            <artifactId>sharding-jdbc-core</artifactId>
            <version>1.5.4</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

配置信息

在配置信息中配置了两个数据库的信息和JPA的简单配置:

##Jpa配置
spring.jpa.database=mysql
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=none

##数据库配置
##数据库database0地址
database0.url=jdbc:mysql://localhost:3306/database0?characterEncoding=utf8&useSSL=false
##数据库database0用户名
database0.username=root
##数据库database0密码
database0.password=root
##数据库database0驱动
database0.driverClassName=com.mysql.jdbc.Driver
##数据库database0名称
database0.databaseName=database0

##数据库database1地址
database1.url=jdbc:mysql://localhost:3306/database1?characterEncoding=utf8&useSSL=false
##数据库database1用户名
database1.username=root
##数据库database1密码
database1.password=root
##数据库database1驱动
database1.driverClassName=com.mysql.jdbc.Driver
##数据库database1名称
database1.databaseName=database1

启动类

启动类加入了@EnableAutoConfiguration排除数据库自动配置，使用@EnableTransactionManagement开启事务，使用@EnableConfigurationProperties注解加入配置实体，启动类完整代码请入所示:

package com.dalaoyang;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@SpringBootApplication
@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
@EnableTransactionManagement(proxyTargetClass = true)
@EnableConfigurationProperties
public class Springboot2ShardingjdbcFkfbApplication {

    public static void main(String[] args) {
        SpringApplication.run(Springboot2ShardingjdbcFkfbApplication.class, args);
    }

}

实体类和数据库操作层

这里没什么好说的，就是简单的实体和Repository，只不过在Repository内加入between方法和in方法用于测试，代码如下所示:

Goods实体类

package com.dalaoyang.entity;

import lombok.Data;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

/**
 * @author yangyang
 * @date 2019/1/29
 */
@Entity
@Table(name="goods")
@Data
public class Goods {
    @Id
    private Long goodsId;

    private String goodsName;

    private Long goodsType;
}

GoodsRepository类

package com.dalaoyang.repository;

import com.dalaoyang.entity.Goods;
import org.springframework.data.jpa.repository.JpaRepository;

import java.util.List;

/**
 * @author yangyang
 * @date 2019/1/29
 */
public interface GoodsRepository extends JpaRepository<Goods, Long> {

    List<Goods> findAllByGoodsIdBetween(Long goodsId1,Long goodsId2);

    List<Goods> findAllByGoodsIdIn(List<Long> goodsIds);
}

数据库配置

本文使用了两个实体来接收数据库信息，并且创建数据源，也可以采用别的方式。首先看一下Database0Config和Database1Config两个类的代码:

Database0Config类

package com.dalaoyang.database;

import com.alibaba.druid.pool.DruidDataSource;
import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import javax.sql.DataSource;

/**
 * @author yangyang
 * @date 2019/1/30
 */
@Data
@ConfigurationProperties(prefix = "database0")
@Component
public class Database0Config {
    private String url;
    private String username;
    private String password;
    private String driverClassName;
    private String databaseName;

    public DataSource createDataSource() {
        DruidDataSource result = new DruidDataSource();
        result.setDriverClassName(getDriverClassName());
        result.setUrl(getUrl());
        result.setUsername(getUsername());
        result.setPassword(getPassword());
        return result;
    }
}

Database1Config类

package com.dalaoyang.database;

import com.alibaba.druid.pool.DruidDataSource;
import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import javax.sql.DataSource;

/**
 * @author yangyang
 * @date 2019/1/30
 */
@Data
@ConfigurationProperties(prefix = "database1")
@Component
public class Database1Config {
    private String url;
    private String username;
    private String password;
    private String driverClassName;
    private String databaseName;

    public DataSource createDataSource() {
        DruidDataSource result = new DruidDataSource();
        result.setDriverClassName(getDriverClassName());
        result.setUrl(getUrl());
        result.setUsername(getUsername());
        result.setPassword(getPassword());
        return result;
    }
}

接下来新建DataSourceConfig用于创建数据源和使用分库分表策略，其中分库分表策略会调用分库算法类和分表算法类，DataSourceConfig类代码如下所示:

package com.dalaoyang.database;


import com.dalaoyang.config.DatabaseShardingAlgorithm;
import com.dalaoyang.config.TableShardingAlgorithm;
import com.dangdang.ddframe.rdb.sharding.api.ShardingDataSourceFactory;
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.table.TableShardingStrategy;
import com.dangdang.ddframe.rdb.sharding.keygen.DefaultKeyGenerator;
import com.dangdang.ddframe.rdb.sharding.keygen.KeyGenerator;
import org.springframework.beans.factory.annotation.Autowired;
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;

/**
 * @author yangyang
 * @date 2019/1/29
 */
@Configuration
public class DataSourceConfig {

    @Autowired
    private Database0Config database0Config;

    @Autowired
    private Database1Config database1Config;

    @Autowired
    private DatabaseShardingAlgorithm databaseShardingAlgorithm;

    @Autowired
    private TableShardingAlgorithm tableShardingAlgorithm;

    @Bean
    public DataSource getDataSource() throws SQLException {
        return buildDataSource();
    }

    private DataSource buildDataSource() throws SQLException {
        //分库设置
        Map<String, DataSource> dataSourceMap = new HashMap<>(2);
        //添加两个数据库database0和database1
        dataSourceMap.put(database0Config.getDatabaseName(), database0Config.createDataSource());
        dataSourceMap.put(database1Config.getDatabaseName(), database1Config.createDataSource());
        //设置默认数据库
        DataSourceRule dataSourceRule = new DataSourceRule(dataSourceMap, database0Config.getDatabaseName());

        //分表设置，大致思想就是将查询虚拟表Goods根据一定规则映射到真实表中去
        TableRule orderTableRule = TableRule.builder("goods")
                .actualTables(Arrays.asList("goods_0", "goods_1"))
                .dataSourceRule(dataSourceRule)
                .build();

        //分库分表策略
        ShardingRule shardingRule = ShardingRule.builder()
                .dataSourceRule(dataSourceRule)
                .tableRules(Arrays.asList(orderTableRule))
                .databaseShardingStrategy(new DatabaseShardingStrategy("goods_id", databaseShardingAlgorithm))
                .tableShardingStrategy(new TableShardingStrategy("goods_type", tableShardingAlgorithm)).build();
        DataSource dataSource = ShardingDataSourceFactory.createDataSource(shardingRule);
        return dataSource;
    }


    @Bean
    public KeyGenerator keyGenerator() {
        return new DefaultKeyGenerator();
    }

}

分库分表算法

由于这里只是简单的分库分表样例，所以分库类这里实现SingleKeyDatabaseShardingAlgorithm类，采用了单分片键数据源分片算法，需要重写三个方法，分别是：

doEqualSharding：SQL中==的规则。
doInSharding：SQL中in的规则。
doBetweenSharding：SQL中between的规则。

本文分库规则是基于值大于20则使用database0，其余使用database1，所以简单if，else就搞定了，分库算法类DatabaseShardingAlgorithm代码如下所示:

package com.dalaoyang.config;

import com.dalaoyang.database.Database0Config;
import com.dalaoyang.database.Database1Config;
import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.database.SingleKeyDatabaseShardingAlgorithm;
import com.google.common.collect.Range;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.util.Collection;
import java.util.LinkedHashSet;

/**
 * 这里使用的都是单键分片策略
 * 示例分库策略是：
 * GoodsId<=20使用database0库
 * 其余使用database1库
 * @author yangyang
 * @date 2019/1/30
 */
@Component
public class DatabaseShardingAlgorithm implements SingleKeyDatabaseShardingAlgorithm<Long> {

    @Autowired
    private Database0Config database0Config;

    @Autowired
    private Database1Config database1Config;

    @Override
    public String doEqualSharding(Collection<String> availableTargetNames, ShardingValue<Long> shardingValue) {
        Long value = shardingValue.getValue();
        if (value <= 20L) {
            return database0Config.getDatabaseName();
        } else {
            return database1Config.getDatabaseName();
        }
    }

    @Override
    public Collection<String> doInSharding(Collection<String> availableTargetNames, ShardingValue<Long> shardingValue) {
        Collection<String> result = new LinkedHashSet<>(availableTargetNames.size());
        for (Long value : shardingValue.getValues()) {
            if (value <= 20L) {
                result.add(database0Config.getDatabaseName());
            } else {
                result.add(database1Config.getDatabaseName());
            }
        }
        return result;
    }

    @Override
    public Collection<String> doBetweenSharding(Collection<String> availableTargetNames,
                                                ShardingValue<Long> shardingValue) {
        Collection<String> result = new LinkedHashSet<>(availableTargetNames.size());
        Range<Long> range = shardingValue.getValueRange();
        for (Long value = range.lowerEndpoint(); value <= range.upperEndpoint(); value++) {
            if (value <= 20L) {
                result.add(database0Config.getDatabaseName());
            } else {
                result.add(database1Config.getDatabaseName());
            }
        }
        return result;
    }
}

分表和分库类似，无非就是实现的类不一样，实现了SingleKeyTableShardingAlgorithm类，策略使用值奇偶分表，分表算法类TableShardingAlgorithm如代码清单所示:

package com.dalaoyang.config;

import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.table.SingleKeyTableShardingAlgorithm;
import com.google.common.collect.Range;
import org.springframework.stereotype.Component;

import java.util.Collection;
import java.util.LinkedHashSet;

/**
 * 这里使用的都是单键分片策略
 * 示例分表策略是：
 * GoodsType为奇数使用goods_1表
 * GoodsType为偶数使用goods_0表
 * @author yangyang
 * @date 2019/1/30
 */
@Component
public class TableShardingAlgorithm implements SingleKeyTableShardingAlgorithm<Long> {

    @Override
    public String doEqualSharding(final Collection<String> tableNames, final ShardingValue<Long> shardingValue) {
        for (String each : tableNames) {
            if (each.endsWith(shardingValue.getValue() % 2 + "")) {
                return each;
            }
        }
        throw new IllegalArgumentException();
    }

    @Override
    public Collection<String> doInSharding(final Collection<String> tableNames, final ShardingValue<Long> shardingValue) {
        Collection<String> result = new LinkedHashSet<>(tableNames.size());
        for (Long value : shardingValue.getValues()) {
            for (String tableName : tableNames) {
                if (tableName.endsWith(value % 2 + "")) {
                    result.add(tableName);
                }
            }
        }
        return result;
    }

    @Override
    public Collection<String> doBetweenSharding(final Collection<String> tableNames,
                                                final ShardingValue<Long> shardingValue) {
        Collection<String> result = new LinkedHashSet<>(tableNames.size());
        Range<Long> range = shardingValue.getValueRange();
        for (Long i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
            for (String each : tableNames) {
                if (each.endsWith(i % 2 + "")) {
                    result.add(each);
                }
            }
        }
        return result;
    }
}

Controller

接下来创建一个Controller进行测试，保存方法使用了插入40条数据，根据我们的规则，会每个库插入20条，同时我这里还创建了三个查询方法，分别是查询全部，between查询，in查询，还有删除全部方法。Controller类代码如下所示:

package com.dalaoyang.controller;

import com.dalaoyang.entity.Goods;
import com.dalaoyang.repository.GoodsRepository;
import com.dangdang.ddframe.rdb.sharding.keygen.KeyGenerator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.ArrayList;
import java.util.List;

/**
 * @author yangyang
 * @date 2019/1/29
 */
@RestController
public class GoodsController {

    @Autowired
    private KeyGenerator keyGenerator;

    @Autowired
    private GoodsRepository goodsRepository;

    @GetMapping("save")
    public String save(){
        for(int i= 1 ; i <= 40 ; i ++){
            Goods goods = new Goods();
            goods.setGoodsId((long) i);
            goods.setGoodsName( "shangpin" + i);
            goods.setGoodsType((long) (i+1));
            goodsRepository.save(goods);
        }
        return "success";
    }

    @GetMapping("select")
    public String select(){
        return goodsRepository.findAll().toString();
    }

    @GetMapping("delete")
    public void delete(){
         goodsRepository.deleteAll();
    }

    @GetMapping("query1")
    public Object query1(){
        return goodsRepository.findAllByGoodsIdBetween(10L, 30L);
    }

    @GetMapping("query2")
    public Object query2(){
        List<Long> goodsIds = new ArrayList<>();
        goodsIds.add(10L);
        goodsIds.add(15L);
        goodsIds.add(20L);
        goodsIds.add(25L);
        return goodsRepository.findAllByGoodsIdIn(goodsIds);
    }
}