Apache ShardingSphere 实现分库分表及读写分离

本文为博主原创，未经允许不得转载:

　　项目demo 源码地址：https://gitee.com/xiangbaxiang/apache-shardingjdbc

　　1. 创建Maven项目，并配置 pom 依赖：

<?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>

    <groupId>org.example</groupId>
    <artifactId>apache-shardingjdbc</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.11.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.8</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <!--排除默认的tomcat-jdbc-->
                <exclusion>
                    <groupId>org.apache.tomcat</groupId>
                    <artifactId>tomcat-jdbc</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.apache.shardingsphere</groupId>
            <artifactId>sharding-jdbc-spring-boot-starter</artifactId>
            <version>4.0.0-RC2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.9</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.22</version>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.3.2</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
              <!--  <version>2.1.3.RELEASE</version>-->
            </plugin>
        </plugins>
    </build>
</project>

　　2.创建实体类

package com.sharding.entity;

import lombok.Data;

@Data
public class User {
    private Long  id ;
    private Integer age ;
    private String name;
    private Long cid;
}

　　3. 创建 mapper 类

package com.sharding.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.sharding.entity.User;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface UserMapper extends BaseMapper<User> {
}

　　4. 创建控制层

package com.sharding.controller;

import com.sharding.entity.User;
import com.sharding.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Random;

@RestController
@RequestMapping("sharding")
public class UserController {

    @Autowired
    private UserMapper userMapper;

    @RequestMapping("saveUser")
    public int saveUser(){
        User user = new User();
        Random random = new Random();
        int value = random.nextInt(20);
        user.setAge(value);
        long longValue = random.nextLong();
        user.setCid(longValue);
        user.setName("test"+value);
        int result = userMapper.insert(user);
        return result;
    }
}

　　5. 创建启动类

package com.sharding;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan(basePackages = "com.sharding.mapper")
public class ApacheShardingJdbcApplication {

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

　　6. 创建分库分表的配置文件

#数据库m1,m2
spring.shardingsphere.datasource.names=m1,m2
spring.shardingsphere.datasource.m1.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.m1.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.m1.url=jdbc:mysql://127.0.0.1:3306/userdb?serverTimezone=GMT%2B8
spring.shardingsphere.datasource.m1.username=root
spring.shardingsphere.datasource.m1.password=zengjian

spring.shardingsphere.datasource.m2.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.m2.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.m2.url=jdbc:mysql://127.0.0.1:3306/userdb2?serverTimezone=GMT%2B8
spring.shardingsphere.datasource.m2.username=root
spring.shardingsphere.datasource.m2.password=zengjian

# 分库策略 根据id取模确定数据进哪个数据库
spring.shardingsphere.sharding.default-database-strategy.inline.sharding-column=age
spring.shardingsphere.sharding.default-database-strategy.inline.algorithm-expression=m$->{age % 2+1}
spring.shardingsphere.sharding.binding-tables=user

# user表进行分表
spring.shardingsphere.sharding.tables.user.actual-data-nodes=m$->{1..2}.user_$->{1..2}

# 分表字段id
spring.shardingsphere.sharding.tables.user.table-strategy.inline.sharding-column=id
# 分表策略 根据id取模,确定数据最终落在那个表中
spring.shardingsphere.sharding.tables.user.table-strategy.inline.algorithm-expression = user_$->{id % 2+1}
#分表列
spring.shardingsphere.sharding.tables.user.key-generator.column=id
#id数据生成算法
spring.shardingsphere.sharding.tables.user.key-generator.type=SNOWFLAKE

spring.shardingsphere.props.sql.show=true
spring.main.allow-bean-definition-overriding=true

　　7. 读写分离的配置文件

#shardingsphere 读写分离,master-slave,可以一主多从
spring.shardingsphere.datasource.names=ds-master,ds-slave0
#主库
spring.shardingsphere.datasource.ds-master.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds-master.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.ds-master.jdbc-url=jdbc:mysql://112.125.26.63:3306/userdb_master?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=UTF-8
spring.shardingsphere.datasource.ds-master.username=root
spring.shardingsphere.datasource.ds-master.password=root
#从库0
spring.shardingsphere.datasource.ds-slave0.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.ds-slave0.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.ds-slave0.jdbc-url=jdbc:mysql://112.125.26.64:3306/userdb_slave?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=UTF-8
spring.shardingsphere.datasource.ds-slave0.username=root
spring.shardingsphere.datasource.ds-slave0.password=root
#从库1
#spring.shardingsphere.datasource.ds-slave1.type=com.alibaba.druid.pool.DruidDataSource
#spring.shardingsphere.datasource.ds-slave1.type=com.zaxxer.hikari.HikariDataSource
#spring.shardingsphere.datasource.ds-slave1.driver-class-name=com.mysql.cj.jdbc.Driver
#spring.shardingsphere.datasource.ds-slave1.jdbc-url=jdbc:mysql://112.125.26.65:3306/shop_ds_slave1?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=UTF-8
#spring.shardingsphere.datasource.ds-slave1.username=root
#spring.shardingsphere.datasource.ds-slave1.password=root

#读写分离主从规则设置，当有2个以上从库时，从库读采用轮询的负载均衡机制
spring.shardingsphere.masterslave.load-balance-algorithm-type=round_robin
spring.shardingsphere.masterslave.name=ms
spring.shardingsphere.masterslave.master-data-source-name=ds-master
spring.shardingsphere.masterslave.slave-data-source-names=ds-slave0

spring.shardingsphere.props.sql.show=true
spring.main.allow-bean-definition-overriding=true

　　8.创建启动类

package com.sharding;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan(basePackages = "com.sharding.mapper")
public class ApacheShardingJdbcApplication {

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

　　9.创建对应数据库：userdb , userdb2 , 并分别执行以下脚本

-- ----------------------------
-- Table structure for user_1
-- ----------------------------
DROP TABLE IF EXISTS `user_1`;
CREATE TABLE `user_1`  (
  `id` bigint(20) NOT NULL,
  `name` varchar(255) CHARACTER SET latin1 COLLATE latin1_swedish_ci NULL DEFAULT NULL,
  `age` int(11) NULL DEFAULT NULL,
  `cid` bigint(20) NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = latin1 COLLATE = latin1_swedish_ci ROW_FORMAT = Compact;

-- ----------------------------
-- Table structure for user_2
-- ----------------------------
DROP TABLE IF EXISTS `user_2`;
CREATE TABLE `user_2`  (
  `id` bigint(20) NOT NULL,
  `name` varchar(255) CHARACTER SET latin1 COLLATE latin1_swedish_ci NULL DEFAULT NULL,
  `age` int(11) NULL DEFAULT NULL,
  `cid` bigint(20) NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = latin1 COLLATE = latin1_swedish_ci ROW_FORMAT = Compact;

　　10. 验证

　　浏览器请求： http://localhost:8080/sharding/saveUser

　　查看日志：可以看到sql 执行的逻辑过程如下

2021-11-13 23:54:20.056  INFO 186124 --- [nio-8080-exec-2] ShardingSphere-SQL                       : SQLStatement: InsertStatement(super=DMLStatement(super=AbstractSQLStatement(type=DML, tables=Tables(tables=[Table(name=user, alias=Optional.absent())]), routeConditions=Conditions(orCondition=OrCondition(andConditions=[AndCondition(conditions=[Condition(column=Column(name=id, tableName=user), operator=EQUAL, compareOperator=null, positionValueMap={}, positionIndexMap={0=0}), Condition(column=Column(name=age, tableName=user), operator=EQUAL, compareOperator=null, positionValueMap={}, positionIndexMap={0=1})])])), encryptConditions=Conditions(orCondition=OrCondition(andConditions=[])), sqlTokens=[TableToken(tableName=user, quoteCharacter=NONE, schemaNameLength=0), SQLToken(startIndex=18)], parametersIndex=4, logicSQL=INSERT INTO user  ( id,
age,
name,
cid )  VALUES  ( ?,
?,
?,
? )), deleteStatement=false, updateTableAlias={}, updateColumnValues={}, whereStartIndex=0, whereStopIndex=0, whereParameterStartIndex=0, whereParameterEndIndex=0), columnNames=[id, age, name, cid], values=[InsertValue(columnValues=[org.apache.shardingsphere.core.parse.old.parser.expression.SQLPlaceholderExpression@62520960, org.apache.shardingsphere.core.parse.old.parser.expression.SQLPlaceholderExpression@14c57902, org.apache.shardingsphere.core.parse.old.parser.expression.SQLPlaceholderExpression@7c661b99, org.apache.shardingsphere.core.parse.old.parser.expression.SQLPlaceholderExpression@6c580fa2])])
2021-11-13 23:54:20.056  INFO 186124 --- [nio-8080-exec-2] ShardingSphere-SQL                       : Actual SQL: m1 ::: INSERT INTO user_2   (id, age, name, cid) VALUES (?, ?, ?, ?) ::: [1459550199242993665, 14, test14, -2186172803516415750]