springboot整合mybatis+sharding-jdbc实现单库分表存储

最近公司项目要对数据库表做分表功能，今天弄了一天，总算把demo运行起来，存取都没问题了，在这里做下记录，希望能给有需要的小伙伴一点点帮助吧！

 

项目架构：springboot2.3 + mybatis + sharding jdbc +mysql

sharding jdbc :用来实现数据库分库、分表 ，推介去官网看看https://shardingsphere.apache.org/index_zh.html

其它就不做介绍了很基础的东西

1.先来张项目架构图

2. maven的pom文件依赖

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
    </dependency>
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
    </dependency>

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>

    <!--热部署自启动工具-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>

    <!--mysql数据库驱动-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <!--数据库连接池-->
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.1.22</version>
    </dependency>
    <!--mybatis依赖-->
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.3</version>
    </dependency>

    <!--<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>-->

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-freemarker</artifactId>
    </dependency>

    <!--分库分表工具-->
    <dependency>
        <groupId>io.shardingsphere</groupId>
        <artifactId>sharding-jdbc-spring-boot-starter</artifactId>
        <version>3.1.0</version>
    </dependency>
</dependencies>

注意sharding jdbc依赖这里有点坑，管网上给的依赖maven没办法下载

3.application.properties配置文件内容

#boot内置tomcat端口
server.port=8080
#mybatis映射文件位置
mybatis.mapper-locations=classpath:mapper/*.xml


#配置sharding数据源
#这里是给取的别名，下面配置要使用
sharding.jdbc.datasource.names=ds 
#指定数据库连接池
sharding.jdbc.datasource.ds.type=com.alibaba.druid.pool.DruidDataSource
#mysql数据库连接驱动，注意我这里是用的mysql8+的，低版本的是com.mysql.jdbc.Driver
sharding.jdbc.datasource.ds.driver-class-name=com.mysql.cj.jdbc.Driver
sharding.jdbc.datasource.ds.url=jdbc:mysql://localhost:3306/baobiao_pc?useUnicode=true&useSSL=false&characterEncoding=utf8&serverTimezone=Asia/Shanghai
sharding.jdbc.datasource.ds.username=root
sharding.jdbc.datasource.ds.password=123456

#分表相关配置  note是我数据库要分表的表前缀，ds.note$->{0..1}这里表示ds数据库中的note0，note1两个表
sharding.jdbc.config.sharding.tables.note.actual-data-nodes=ds.note$->{0..1}
# 配置分表策略
sharding.jdbc.config.sharding.tables.note.table-strategy.inline.sharding-column=id
# 配置分片算法
sharding.jdbc.config.sharding.tables.note.table-strategy.inline.algorithm-expression=note$->{id % 2}
sharding.jdbc.config.sharding.tables.note.key-generator-column-name=id

# 打印执行的数据库以及语句
sharding.jdbc.config.props..sql.show=true
#spring.main.allow-bean-definition-overriding=true

 

4. 然后是id生成工具类，分表没办法使用主键自动生成

public class IdWorker {
    //下面两个每个5位，加起来就是10位的工作机器id
    private long workerId;    //工作id
    private long datacenterId;   //数据id
    //12位的***
    private long sequence;

    public IdWorker(long workerId, long datacenterId, long sequence){
        // sanity check for workerId
        if (workerId > maxWorkerId || workerId < 0) {
            throw new IllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0",maxWorkerId));
        }
        if (datacenterId > maxDatacenterId || datacenterId < 0) {
            throw new IllegalArgumentException(String.format("datacenter Id can't be greater than %d or less than 0",maxDatacenterId));
        }
        System.out.printf("worker starting. timestamp left shift %d, datacenter id bits %d, worker id bits %d, sequence bits %d, workerid %d",
                timestampLeftShift, datacenterIdBits, workerIdBits, sequenceBits, workerId);

        this.workerId = workerId;
        this.datacenterId = datacenterId;
        this.sequence = sequence;
    }
    //初始时间戳
    private long twepoch = 1288834974657L;

    //长度为5位
    private long workerIdBits = 5L;
    private long datacenterIdBits = 5L;
    //最大值
    private long maxWorkerId = -1L ^ (-1L << workerIdBits);
    private long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);
    //***id长度
    private long sequenceBits = 12L;
    //***最大值
    private long sequenceMask = -1L ^ (-1L << sequenceBits);

    //工作id需要左移的位数，12位
    private long workerIdShift = sequenceBits;
    //数据id需要左移位数 12+5=17位
    private long datacenterIdShift = sequenceBits + workerIdBits;
    //时间戳需要左移位数 12+5+5=22位
    private long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;

    //上次时间戳，初始值为负数
    private long lastTimestamp = -1L;

    public long getWorkerId(){
        return workerId;
    }

    public long getDatacenterId(){
        return datacenterId;
    }

    public long getTimestamp(){
        return System.currentTimeMillis();
    }
    //下一个ID生成算法
    public synchronized long nextId() {
        long timestamp = timeGen();

        //获取当前时间戳如果小于上次时间戳，则表示时间戳获取出现异常
        if (timestamp < lastTimestamp) {
            System.err.printf("clock is moving backwards.  Rejecting requests until %d.", lastTimestamp);
            throw new RuntimeException(String.format("Clock moved backwards.  Refusing to generate id for %d milliseconds",
                    lastTimestamp - timestamp));
        }

        //获取当前时间戳如果等于上次时间戳（同一毫秒内），则在***加一；否则***赋值为0，从0开始。
        sequence = (sequence + 1) & sequenceMask;
        /*if (lastTimestamp == timestamp) {
            sequence = (sequence + 1) & sequenceMask;
            if (sequence == 0) {
                timestamp = tilNextMillis(lastTimestamp);
            }
        } else {
            sequence = 0;
        }*/

        //将上次时间戳值刷新
        lastTimestamp = timestamp;

        /**
         * 返回结果：
         * (timestamp - twepoch) << timestampLeftShift) 表示将时间戳减去初始时间戳，再左移相应位数
         * (datacenterId << datacenterIdShift) 表示将数据id左移相应位数
         * (workerId << workerIdShift) 表示将工作id左移相应位数
         * | 是按位或运算符，例如：x | y，只有当x，y都为0的时候结果才为0，其它情况结果都为1。
         * 因为个部分只有相应位上的值有意义，其它位上都是0，所以将各部分的值进行 | 运算就能得到最终拼接好的id
         */
        return ((timestamp - twepoch) << timestampLeftShift) |
                (datacenterId << datacenterIdShift) |
                (workerId << workerIdShift) |
                sequence;
    }

    //获取时间戳，并与上次时间戳比较
    private long tilNextMillis(long lastTimestamp) {
        long timestamp = timeGen();
        while (timestamp <= lastTimestamp) {
            timestamp = timeGen();
        }
        return timestamp;
    }

    //获取系统时间戳
    private long timeGen(){
        return System.currentTimeMillis();
    }

    //---------------测试---------------
    public static void main(String[] args) {
        IdWorker worker = new IdWorker(1,1,1);
        for (int i = 0; i < 20; i++) {

            try {
                Thread.sleep(1000);
            }catch (Exception e){
                e.printStackTrace();
            }
            System.out.println(worker.nextId());
        }
    }
}

5.然后是springboot启动类

package com.sbkj;

import com.sbkj.util.IdWorker;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;

import java.util.Date;

@SpringBootApplication
@MapperScan("com.sbkj.mapper")
public class DemoApplication {

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

    /**
     * 实例id生成工具类，交由spring管理
     * @return
     */
    @Bean
    public IdWorker getIdWorker(){
        return new IdWorker(1,1,1);
    }

}

6.最后是controller,没什么业务就没写service了，实体和dao(mapper)就用的mybatis自动生成的就不贴出来了

package com.sbkj.controller;

import com.sbkj.entity.Note;
import com.sbkj.mapper.NoteMapper;
import com.sbkj.util.IdWorker;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.util.List;

@RestController
public class TestController {

    @Autowired
    NoteMapper noteMapper;
    @Autowired
    IdWorker idWorker;

    @RequestMapping(value = "/save", method = RequestMethod.POST)
    public Note index(Note note){
        note.setId(idWorker.nextId());//主键生成
        noteMapper.insert(note);
        return note;
    }

    @RequestMapping(value = "/book", method = RequestMethod.GET)
    public List<Note> getItems(){
        return noteMapper.getNoteList();
    }

    @RequestMapping(value = "/getNote")
    public Note getNote(Long id){
        return noteMapper.selectByPrimaryKey(id);
    }
}

最最后献上运行效果图，添加了2条数据，通过配置的id分片算法分别添加进去了

在来张取数据的，可以看到2张表都查询了