shardingjdbc按月份分表

首先，准备一个分片的表

CREATE TABLE `t_log` (
  `id` bigint NOT NULL AUTO_INCREMENT,
  `log` varchar(256) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
  `time` varchar(12) DEFAULT NULL,
  `created_time` datetime DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb3;

接着，创建一个新的项目，引入相关依赖，这用的是sharding-jdbc 4.0.0-RC1版本

        org.springframework.boot
        spring-boot-starter-parent
        1.5.3.RELEASE
        
    
 
    
        1.8
        UTF-8
    
 
    
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.mybatis.spring.boot
            mybatis-spring-boot-starter
            1.3.0
        
        
            mysql
            mysql-connector-java
            8.0.22
            runtime
        
        
            org.apache.shardingsphere
            sharding-jdbc-spring-boot-starter
            4.0.0-RC1
        
        
            com.alibaba
            druid-spring-boot-starter
            1.1.21
        
    
 
    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
            
                org.mybatis.generator
                mybatis-generator-maven-plugin
                1.3.2
                
                    true
                    false
                
                
                    
                        mysql
                        mysql-connector-java
                        8.0.22
                    
                
            
        
    

添加配置：

# 配置存放到内存中
spring.shardingsphere.mode.type=Memory
# 打印sql日志
spring.shardingsphere.props.sql.show=true
# 配置数据源
spring.shardingsphere.datasource.names=ds
spring.shardingsphere.datasource.ds.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.ds.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.ds.url=jdbc:mysql://192.168.3.4:3306/sharding?autoReconnect=true&useUnicode=true&characterEncoding=utf8&allowMultiQueries=true&useSSL=false
spring.shardingsphere.datasource.ds.username=root
spring.shardingsphere.datasource.ds.password=root
 
# 配置数据节点，这里是按月分表，时间范围设置在202201 ~ 210012
spring.shardingsphere.sharding.tables.t_log.actual-data-nodes=ds.t_log_$->{2022..2100}0$->{1..9},ds.t_log_$->{2022..2100}1$->{0..2}
# 使用标准分片策略，配置分片字段
spring.shardingsphere.sharding.tables.t_log.table-strategy.standard.sharding-column=time
# 配置精确、范围查询分片算法
spring.shardingsphere.sharding.tables.t_log.table-strategy.standard.precise-algorithm-class-name=com.example.springboot.algorithm.TimeShardingAlgorithm
spring.shardingsphere.sharding.tables.t_log.table-strategy.standard.range-algorithm-class-name=com.example.springboot.algorithm.TimeShardingAlgorithm
# 配置主键以及生成算法
spring.shardingsphere.sharding.tables.t_log.key-generator.column=id
spring.shardingsphere.sharding.tables.t_log.key-generator.type=SNOWFLAKE

这里要注意下precise-algorithm是配置精确分片算法实现类（如=、in），range-algorithm是配置范围分片算法实现类（如between and），实现如下：

package com.example.springboot.algorithm;
 
import com.google.common.collect.Range;
import org.apache.shardingsphere.api.sharding.standard.PreciseShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.PreciseShardingValue;
import org.apache.shardingsphere.api.sharding.standard.RangeShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.RangeShardingValue;
 
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Collection;
 
/**
 * 分片算法，按月分片
 */
public class TimeShardingAlgorithm implements PreciseShardingAlgorithm, RangeShardingAlgorithm {
 
    /**
     * 需要空构造方法
     */
    public TimeShardingAlgorithm() {}
 
    /**
     * 时间格式
     */
    private static final DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyyMMdd");
 
    /**
     * 精确分片
     * @param collection
     * @param preciseShardingValue
     * @return
     */
    @Override
    public String doSharding(Collection collection, PreciseShardingValue preciseShardingValue) {
        return buildShardingTable(preciseShardingValue.getLogicTableName(), preciseShardingValue.getValue());
    }
 
    /**
     * 构建分片后的表名
     * @param logicTableName
     * @param date
     * @return
     */
    private String buildShardingTable(String logicTableName, String date) {
        StringBuffer stringBuffer = new StringBuffer(logicTableName).append("_").append(date, 0, 6);
        return stringBuffer.toString();
    }
 
    /**
     * 范围分片
     * @param collection
     * @param rangeShardingValue
     * @return
     */
    @Override
    public Collection doSharding(Collection collection, RangeShardingValue rangeShardingValue) {
        Range valueRange = rangeShardingValue.getValueRange();
        String lower = valueRange.lowerEndpoint();
        String upper = valueRange.upperEndpoint();
 
        LocalDate start = LocalDate.parse(lower, DATE_TIME_FORMATTER);
        LocalDate end = LocalDate.parse(upper, DATE_TIME_FORMATTER);
 
        Collection tables = new ArrayList<>();
        while (start.compareTo(end) <= 0) {
            tables.add(buildShardingTable(rangeShardingValue.getLogicTableName(), start.format(DATE_TIME_FORMATTER)));
            start = start.plusMonths(1L);
        }
        
        // collection配置的数据节点表，这里是排除不存在配置中的表
        collection.retainAll(tables);
        return collection;
    }
 
}