SpringBoot集成Sharding-JDBC-5.3.0实现按月动态建表分表

 Sharding-JDBC系列

1、Sharding-JDBC分库分表的基本使用

2、Sharding-JDBC分库分表之SpringBoot分片策略

3、Sharding-JDBC分库分表之SpringBoot主从配置

4、SpringBoot集成Sharding-JDBC-5.3.0分库分表

5、SpringBoot集成Sharding-JDBC-5.3.0实现按月动态建表分表

前言

随着业务量的递增，项目产生海量的数据，在某些场景中，需要将数据按月存储。本篇基于Sharding-JDBC 5.3.0，分享一下按月自动建表以及分表的实现。

准备工作

创建一个数据库，创建一张表，表名为tb_order。该表作为基准表。

引入依赖

<?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"><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.7.1</version><relativePath/> <!-- lookup parent from repository --></parent><modelVersion>4.0.0</modelVersion><artifactId>Sharding-JDBC-demo2</artifactId><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.1</version></dependency><dependency><groupId>org.apache.shardingsphere</groupId><artifactId>shardingsphere-jdbc-core</artifactId><version>5.3.0</version></dependency><dependency><groupId>org.yaml</groupId><artifactId>snakeyaml</artifactId><version>1.33</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.28</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.2.6</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.22</version><scope>compile</scope></dependency><!--<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-devtools</artifactId><optional>true</optional><scope>runtime</scope></dependency>--></dependencies></project>

1）引入shardingsphere-jdbc-core 5.3.0 的版本；

2）项目中不要引入spring-boot-devtools，否则在调试启动时，会报错；

spring-boot-devtools 会在类路径上的文件发生更改时自动重启，方便开发调试。在项目部署时，通过 java -jar 启动项目时，会自动禁用开发工具。报错的原因下面说明。

分片规则配置

4.1 application.yml

server:port: 8080
spring:main:# 处理连接池冲突allow-bean-definition-overriding: truedatasource:# shardingsphere5.3.0引入ShardingSphereDriver数据库驱动driver-class-name: org.apache.shardingsphere.driver.ShardingSphereDriverurl: jdbc:shardingsphere:classpath:sharding.yml

指定分片规则的文件为sharding.yml。

4.2 sharding.yml

dataSources:order_ds:dataSourceClassName: com.zaxxer.hikari.HikariDataSourcedriverClassName: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/shardingjdbctest?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=falseusername: rootpassword: 123456rules:
- !SHARDINGtables:tb_order: #逻辑表actualDataNodes: order_ds.tb_order  #表是自动创建keyGenerateStrategy: # 指定主键生成策略column: order_idkeyGeneratorName: snowflaketableStrategy:standard: shardingColumn: order_time   #分片键shardingAlgorithmName: custom-time-shardingshardingAlgorithms:  #分片算法custom-time-sharding:type: CLASS_BASED   #自定义类props:strategy: standardalgorithmClassName: com.jingai.sharding.jdbc.algorithm.OrderTimeShardingAlgorithm  #分片算法keyGenerators:  # 主键生成器snowflake:type: SNOWFLAKE
props:sql-show: true  # 是否打印sql

1）配置真实表为tb_order，作为分表的表前缀；

2）配置分表策略为standard标准策略，以订单创建日期为分片键；

3）配置分表算法为自定义类OrderTimeShardingAlgorithm；

分片算法OrderTimeShardingAlgorithm

package com.jingai.sharding.jdbc.algorithm;@Slf4j
public class OrderTimeShardingAlgorithm implements StandardShardingAlgorithm<Date> {private static final DateFormat TABLE_SHARD_TIME_FORMAT = new SimpleDateFormat("yyyyMM");// 表分片符号。如：tb_order_202407private static final String TABLE_SPLIT_SYMBOL = "_";private Properties props;@Overridepublic String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<Date> shardingValue) {String logicTableName = shardingValue.getLogicTableName();log.info("精准分片，逻辑表名：{}，节点表名：{}", logicTableName, availableTargetNames);Date time = shardingValue.getValue();String result = logicTableName + TABLE_SPLIT_SYMBOL + TABLE_SHARD_TIME_FORMAT.format(time);// 在配置中，只配置了逻辑表名。如果只有一个，且是逻辑表名，说明需要获取所有表名initAvailableTargetNames(availableTargetNames, logicTableName);return getAndCreateShardingTable(logicTableName, result, availableTargetNames);}@Overridepublic Collection<String> doSharding(Collection<String> availableTargetNames, RangeShardingValue<Date> shardingValue) {String logicTableName = shardingValue.getLogicTableName();log.info("精准分片，逻辑表名：{}，节点表名：{}", logicTableName, availableTargetNames);// 在配置中，只配置了逻辑表名。如果只有一个，且是逻辑表名，说明需要获取所有表名initAvailableTargetNames(availableTargetNames, logicTableName);Range<Date> valueRange = shardingValue.getValueRange();// 如果没有最大值或最小值，则全库扫描if(!valueRange.hasLowerBound() || !valueRange.hasUpperBound()) {return availableTargetNames;}Date min = valueRange.lowerEndpoint();Date max = valueRange.upperEndpoint();Set<String> rs = new HashSet<>();while (min.compareTo(max) <= 0) {String tableName = logicTableName + "_" + TABLE_SHARD_TIME_FORMAT.format(min);rs.add(tableName);min = DateUtils.addMonths(min, 1);}return getAndCreateShardingTable(logicTableName, rs, availableTargetNames);}private void initAvailableTargetNames(Collection<String> availableTargetNames, String logicTableName) {if(availableTargetNames.size() == 1 && availableTargetNames.contains(logicTableName)) {Set<String> allTableNameBySchema = ShardingAlgorithmUtil.getAllTableNameBySchema(logicTableName);availableTargetNames.clear();availableTargetNames.addAll(allTableNameBySchema);}}/*** 检查可用的真实表，如果表名不存在，则创建新表* @param logicTableName 逻辑表* @param resultTableNames 操作需要的真实表* @param availableTargetNames 可用的真实表* @return 分片的真实表*/private List<String> getAndCreateShardingTable(String logicTableName, Set<String> resultTableNames, Collection<String> availableTargetNames) {return resultTableNames.stream().map(name -> getAndCreateShardingTable(logicTableName, name, availableTargetNames)).collect(Collectors.toList());}/*** 检查可用的真实表，如果表名不存在，则创建新表* @param logicTableName* @param resultTableName* @param availableTargetNames* @return*/private String getAndCreateShardingTable(String logicTableName, String resultTableName, Collection<String> availableTargetNames) {if(availableTargetNames.contains(resultTableName)) {return resultTableName;}boolean rs = ShardingAlgorithmUtil.createShardingTable(logicTableName, resultTableName);if(rs) {availableTargetNames.add(resultTableName);return resultTableName;}return null;}@Overridepublic Properties getProps() {return props;}@Overridepublic void init(Properties properties) {this.props = properties;}
}

1）实现StandardShardingAlgorithm接口，重写doSharding()方法；

2）根据传入的时间分片值，解析出年月，和逻辑表组合，为实际操作的真实表；

3）如果当前的真实表不存在，则调用工具类ShardingAlgorithmUtil创建一个真实表；

工具类ShardingAlgorithmUtil

package com.jingai.sharding.jdbc.util;@Slf4j
public class ShardingAlgorithmUtil {// 表分片符号。如：tb_order_202407private static final String TABLE_SPLIT_SYMBOL = "_";// 配置的数据库源private volatile static Map<String, Map<String, Object>> dataSources = null;public static void init(String url) {Assert.hasText(url, "分片策略不能为空");log.info("数据源获取...");byte[] bytes = new ShardingSphereDriverURL(url).toConfigurationBytes();try {YamlRootConfiguration yamlRootConfiguration = YamlEngine.unmarshal(bytes, YamlRootConfiguration.class);dataSources = yamlRootConfiguration.getDataSources();} catch(Exception e) {e.printStackTrace();log.error("分片策略配置解析失败");throw new IllegalArgumentException("分片策略解析失败");}}/*** 获取所有真实表名*/public static Set<String> getAllTableNameBySchema(String logicTableName) {Assert.notNull(dataSources, "分片策略配置未初始化");Set<String> rs = new HashSet<>();// 获取配置的数据源String startTable = logicTableName + TABLE_SPLIT_SYMBOL;for (Map<String, Object> dataSource : dataSources.values()) {try (Connection conn = DriverManager.getConnection(dataSource.get("url").toString(),dataSource.get("username").toString(), dataSource.get("password").toString())){Statement statement = conn.createStatement();ResultSet resultSet = statement.executeQuery("show tables like '" + startTable + "%'");while (resultSet.next()) {String tableName = resultSet.getString(1);if(StringUtils.hasText(tableName) && tableName.replaceFirst(startTable, "").matches("\\d{6}")) {rs.add(tableName);}}} catch(Exception e) {e.printStackTrace();throw new IllegalArgumentException("数据库连接失败");}}return rs;}/*** 创建分表* @param logicTableName* @param resultTableName* @return*/public static boolean createShardingTable(String logicTableName, String resultTableName) {synchronized (logicTableName.intern()) {for (Map<String, Object> dataSource : dataSources.values()) {try (Connection conn = DriverManager.getConnection(dataSource.get("url").toString(),dataSource.get("username").toString(), dataSource.get("password").toString())){Statement statement = conn.createStatement();log.info("创建{}表", resultTableName);statement.execute("create table if not exists `" + resultTableName + "` like `" + logicTableName + "`;");} catch(Exception e) {e.printStackTrace();throw new IllegalArgumentException("数据库连接失败");}}return true;}}}

1）init(String url) 初始化方法，通过传入的url（application.yml中配置的spring.datasource.url），解析分片配置文件，得到配置的datasources信息；

2）getAllTableNameBySchema(String logicTableName)，通过传入的逻辑表（配置中的tb_order），结合配置的datasources信息，创建连接，从数据库中获取表名以tb_order为前缀的表。即数据库中的真实表；

真实表只需从主库中获取即可，此处可以完善。

3）createShardingTable()，结合配置的datasources信息，创建连接，创建真实表；

初始化类

package com.jingai.sharding.jdbc.listener;@Component
@Slf4j
public class ShardingInitRunner implements InitializingBean {@Value("${spring.datasource.url}")private String url;@Overridepublic void afterPropertiesSet() throws Exception {log.info("sharding初始化...");ShardingAlgorithmUtil.init(url);}}

该类获取spring.datasource.url的配置值，在初始化方法中，调用ShardingAlgorithmUtil.init(url)，初始化ShardingAlgorithmUtil中的datasource值。

1）如果引入了spring-boot-devtools依赖，开启开发工具。项目启动的时候，ShardingAlgorithmUtil类的类加载器为devtools包下的RestartClassLoader，并执行了初始化，获取了datasources；

2）在分片算法OrderTimeShardingAlgorithm的类加载器为AppClassLoader，OrderTimeShardingAlgorithm中调用ShardingAlgorithmUtil时，会用AppClassLoader重新加载一次ShardingAlgorithmUtil，此时的datasources为null；

3）此时执行ShardingAlgorithmUtil操作数据库时，会报空指针；

如果一定要引入spring-boot-devtools依赖，可以在项目的resources目录下增加一个文件META-INF/spring-devtools.properties，在文件下添加RestartClassLoader额外要加载的包的信息。代码如下：

restart.include.shardingsphere=/shardingsphere-[\\w\\d-\.]+\.jar

OrderTimeShardingAlgorithm是在shardingsphere中使用AppClassLoader加载的，所以设置shardingsphere使用RestartClassLoader加载。

 实体类

package com.jingai.sharing.jdbc.entity;@Data
@ToString
@TableName("tb_order")
public class OrderEntity {private long orderId;private long memberId;private float totalPrice;private String status;private Date orderTime;}

在实体类中，@TableName指定配置中的逻辑表。

Mapper类

package com.jingai.sharing.jdbc.dao;public interface OrderMapper extends BaseMapper<OrderEntity> {@Insert("insert into tb_order(member_id, total_price, status, order_time) values " +"(#{memberId}, #{totalPrice}, #{status}, #{orderTime})")@Options(useGeneratedKeys = true, keyProperty = "orderId")int insert2(OrderEntity order);
}

在4.2的配置中，通过key-generator设置了逻辑表的主键生成策略为雪花算法。当进行数据插入时，需要编写新的插入接口，不能直接使用Mybatis-plus中的insert()接口。因为在默认的insert()接口中，实体对象的orderId为0，不会走配置的雪花算法。

Service类

package com.jingai.sharing.jdbc.service;@Service
public class OrderService extends ServiceImpl<OrderMapper, OrderEntity> {@Resourceprivate OrderMapper orderMapper;public long insert2(OrderEntity order) {int rs = orderMapper.insert2(order);return rs > 0 ? order.getOrderId() : 0;}}

为了便于测试，此处省略了Service的接口类。

Controller类

@RestController
public class OrderController {@Resourceprivate OrderService orderService;@RequestMapping("order")public String order(OrderEntity order) {order.setOrderTime(new Date());long insert = orderService.insert2(order);return insert > 0 ? "success" : "fail";}@RequestMapping("list")public List<OrderEntity> list() {return orderService.list();}}

小结

以上为本篇分享的全部内容。以下做一个小结：

1）创建一个基准表tb_order；

2）配置分片规则：标准策略、以订单时间为分片键、自定义分片算法；

3）在分片算法中，根据分片键的值日期值，找到对应月份的表。如果真实表不存在，则创建；

关于本篇内容你有什么自己的想法或独到见解，欢迎在评论区一起交流探讨下吧。