Apache ShardingSphere 初识使用

一 什么是 ShardingSphere？

1.1 背景：为什么需要分库分表？

随着系统数据量和用户量不断增长，传统单体数据库容易遇到瓶颈：

• 写入/查询压力大：单表千万级数据，索引效率下降。

• 存储超限：单机磁盘空间和 IOPS 不堪重负。

• 水平扩展困难：业务难以横向拓展。

为了解决这些问题，开发者往往采用 分库分表 技术，将一张大表分成多个小表，分布在不同数据库中，实现水平扩展和负载均衡。

1.2 什么是 Apache ShardingSphere？

Apache ShardingSphere 是一款开源的 分布式数据库中间件框架，可以帮助开发者轻松实现：

• 分库分表

• 读写分离

• 分布式事务

• 数据脱敏

• 可观测性 & 扩展治理能力

ShardingSphere 核心组件包括：

1.3 ShardingSphere-JDBC 的核心功能

二、实践部分：Java + H2 实现分库分表

示例：使用 Java 原生程序 + ShardingSphere-JDBC + H2 内存数据库，模拟一个电商订单系统按 user_id 分库，order_id 分表。

2.1 项目结构

• 使用 H2 数据库模拟两个库 ds0, ds1

• 每个库中创建两个分表 t_order_0, t_order_1

• 逻辑表名：t_order

2.2 Maven 依赖配置

<dependencies>
    <dependency>
        <groupId>org.apache.shardingsphere</groupId>
        <artifactId>shardingsphere-jdbc-core</artifactId>
        <version>5.4.1</version>
    </dependency>
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <version>2.2.220</version>
    </dependency>
    <dependency>
        <groupId>com.zaxxer</groupId>
        <artifactId>HikariCP</artifactId>
        <version>5.0.1</version>
    </dependency>
</dependencies>

2.3 核心代码结构

1. 创建真实表（物理分表）

public static void createTables() throws SQLException {
    for (int i = 0; i < 2; i++) {
        String db = "ds" + i;
        try (Connection conn = DriverManager.getConnection("jdbc:h2:mem:" + db + ";DB_CLOSE_DELAY=-1;MODE=MySQL", "sa", "")) {
            Statement stmt = conn.createStatement();
            for (int j = 0; j < 2; j++) {
                stmt.execute(String.format("""
                    CREATE TABLE IF NOT EXISTS t_order_%d (
                        order_id BIGINT PRIMARY KEY,
                        user_id INT,
                        status VARCHAR(50)
                    )
                """, j));
            }
        }
    }
}

2. 配置分库分表数据源

public static DataSource createDataSource() throws SQLException {
    Map<String, DataSource> dataSourceMap = new HashMap<>();

    for (int i = 0; i < 2; i++) {
        HikariDataSource ds = new HikariDataSource();
        ds.setJdbcUrl("jdbc:h2:mem:ds" + i + ";DB_CLOSE_DELAY=-1;MODE=MySQL");
        ds.setUsername("sa");
        ds.setPassword("");
        dataSourceMap.put("ds" + i, ds);
    }

    ShardingTableRuleConfiguration orderTableRule = new ShardingTableRuleConfiguration(
        "t_order", "ds${0..1}.t_order_${0..1}");

    orderTableRule.setDatabaseShardingStrategy(
        new StandardShardingStrategyConfiguration("user_id", "dbSharding"));
    orderTableRule.setTableShardingStrategy(
        new StandardShardingStrategyConfiguration("order_id", "tableSharding"));

    ShardingRuleConfiguration config = new ShardingRuleConfiguration();
    config.getTables().add(orderTableRule);
    config.getShardingAlgorithms().put("dbSharding",
        new AlgorithmConfiguration("INLINE", props("algorithm-expression", "ds${user_id % 2}")));
    config.getShardingAlgorithms().put("tableSharding",
        new AlgorithmConfiguration("INLINE", props("algorithm-expression", "t_order_${order_id % 2}")));

    return ShardingSphereDataSourceFactory.createDataSource(dataSourceMap, List.of(config), new Properties());
}

3. 插入与查询数据

public static void insertOrder(DataSource ds, long orderId, int userId, String status) throws SQLException {
    try (Connection conn = ds.getConnection()) {
        PreparedStatement ps = conn.prepareStatement("INSERT INTO t_order (order_id, user_id, status) VALUES (?, ?, ?)");
        ps.setLong(1, orderId);
        ps.setInt(2, userId);
        ps.setString(3, status);
        ps.executeUpdate();
    }
}

public static void queryOrders(DataSource ds) throws SQLException {
    try (Connection conn = ds.getConnection()) {
        ResultSet rs = conn.createStatement().executeQuery("SELECT * FROM t_order");
        while (rs.next()) {
            System.out.printf("order_id=%d, user_id=%d, status=%s%n",
                    rs.getLong("order_id"),
                    rs.getInt("user_id"),
                    rs.getString("status"));
        }
    }
}

2.4 程序入口

public static void main(String[] args) throws Exception {
    createTables();  // 创建实际分表
    DataSource shardingDataSource = createDataSource();

    insertOrder(shardingDataSource, 1001, 1, "INIT");
    insertOrder(shardingDataSource, 1002, 2, "PAID");
    insertOrder(shardingDataSource, 1003, 3, "SHIPPED");

    queryOrders(shardingDataSource);
}

 输出示例

order_id=1001, user_id=1, status=INIT
order_id=1002, user_id=2, status=PAID
order_id=1003, user_id=3, status=SHIPPED

ShardingSphere 已自动根据你配置的策略将数据路由到对应的库和表！

总结

Apache ShardingSphere 提供了强大、灵活的分库分表能力，通过合理配置可以极大提升系统的性能与扩展性：

• 分片策略灵活，支持多种规则或自定义算法

• 配置简单，无需改动业务 SQL

• 兼容性强，支持 JDBC、Spring Boot、YAML 等多种使用方式

无论你是中小项目的快速原型，还是大规模高并发系统，ShardingSphere 都是一个值得一试的解决方案。

完整代码

package org.example;

import com.zaxxer.hikari.HikariDataSource;
import org.apache.shardingsphere.driver.api.ShardingSphereDataSourceFactory;

import org.apache.shardingsphere.infra.config.algorithm.AlgorithmConfiguration;
import org.apache.shardingsphere.sharding.api.config.ShardingRuleConfiguration;
import org.apache.shardingsphere.sharding.api.config.rule.ShardingTableRuleConfiguration;
import org.apache.shardingsphere.sharding.api.config.strategy.sharding.StandardShardingStrategyConfiguration;

import javax.sql.DataSource;
import java.sql.*;
import java.util.*;

public class ShardingH2Example {

    public static void main(String[] args) throws Exception {
        createTables(); //  注意：用 DriverManager 直连底层 db 建表

        DataSource shardingDataSource = createDataSource();

        // 插入测试数据
        insertOrder(shardingDataSource, 1001, 1, "INIT");
        insertOrder(shardingDataSource, 1002, 2, "PAID");
        insertOrder(shardingDataSource, 1003, 3, "SHIPPED");

        // 查询测试数据
        queryOrders(shardingDataSource);
    }


    public static DataSource createDataSource() throws Exception {
        Map<String, DataSource> dataSourceMap = new HashMap<>();

        // 模拟两个库：ds0 和 ds1（分别用两个内存 H2 实例模拟）
        for (int i = 0; i < 2; i++) {
            HikariDataSource ds = new HikariDataSource();
            ds.setJdbcUrl("jdbc:h2:mem:ds" + i + ";DB_CLOSE_DELAY=-1;MODE=MySQL");
            ds.setUsername("sa");
            ds.setPassword("");
            dataSourceMap.put("ds" + i, ds);
        }

        // 分表规则配置
        ShardingTableRuleConfiguration orderTableRule = new ShardingTableRuleConfiguration(
                "t_order", "ds${0..1}.t_order_${0..1}");

        // 分库策略（user_id）
        orderTableRule.setDatabaseShardingStrategy(new StandardShardingStrategyConfiguration(
                "user_id", "dbSharding"));

        // 分表策略（order_id）
        orderTableRule.setTableShardingStrategy(new StandardShardingStrategyConfiguration(
                "order_id", "tableSharding"));

        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(orderTableRule);

        Properties dbProps = new Properties();
        dbProps.setProperty("algorithm-expression", "ds${user_id % 2}");
        shardingRuleConfig.getShardingAlgorithms().put("dbSharding",
                new AlgorithmConfiguration("INLINE", dbProps));

        Properties tableProps = new Properties();
        tableProps.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        shardingRuleConfig.getShardingAlgorithms().put("tableSharding",
                new AlgorithmConfiguration("INLINE", tableProps));

        return ShardingSphereDataSourceFactory.createDataSource(dataSourceMap, List.of(shardingRuleConfig), new Properties());
    }

    public static void createTables() throws SQLException {
        for (int i = 0; i < 2; i++) {
            String dbName = "ds" + i;
            try (Connection conn = DriverManager.getConnection("jdbc:h2:mem:" + dbName + ";DB_CLOSE_DELAY=-1;MODE=MySQL", "sa", "")) {
                Statement stmt = conn.createStatement();
                for (int j = 0; j < 2; j++) {
                    String sql = String.format("""
                        CREATE TABLE IF NOT EXISTS t_order_%d (
                            order_id BIGINT PRIMARY KEY,
                            user_id INT,
                            status VARCHAR(50)
                        )
                """, j);
                    stmt.execute(sql);
                }
            }
        }
    }


    // 辅助方法用于手动连接底层 H2 数据源
    private static HikariDataSource getH2DataSource(String name) {
        HikariDataSource ds = new HikariDataSource();
        ds.setJdbcUrl("jdbc:h2:mem:" + name + ";DB_CLOSE_DELAY=-1;MODE=MySQL");
        ds.setUsername("sa");
        ds.setPassword("");
        return ds;
    }


    public static void insertOrder(DataSource ds, long orderId, int userId, String status) throws SQLException {
        try (Connection conn = ds.getConnection()) {
            PreparedStatement ps = conn.prepareStatement("INSERT INTO t_order (order_id, user_id, status) VALUES (?, ?, ?)");
            ps.setLong(1, orderId);
            ps.setInt(2, userId);
            ps.setString(3, status);
            ps.executeUpdate();
        }
    }

    public static void queryOrders(DataSource ds) throws SQLException {
        try (Connection conn = ds.getConnection()) {
            ResultSet rs = conn.createStatement().executeQuery("SELECT * FROM t_order");
            System.out.println("Query Results:");
            while (rs.next()) {
                System.out.printf("order_id: %d, user_id: %d, status: %s%n",
                        rs.getLong("order_id"),
                        rs.getInt("user_id"),
                        rs.getString("status"));
            }
        }
    }
}