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ShardingJDBC底层项目实战：新手入门教程

互换的青春
2024-10-11 12:57:55浏览 77
概述

本文深入探讨了ShardingJDBC底层项目实战，涵盖了ShardingJDBC的基本概念、核心功能和实际应用场景。文章详细介绍了ShardingJDBC的数据分片、读写分离、事务管理等功能，并提供了丰富的示例代码。通过项目实战案例和部署运维指导，帮助读者全面理解ShardingJDBC的使用方法和优化策略。

ShardingJDBC简介

ShardingJDBC的基本概念

ShardingJDBC 是阿里巴巴开源的一款分布式数据库中间件，主要功能包括数据库分片、读写分离、分布式事务等，旨在让分布式数据库的使用像使用单机数据库一样简单。

ShardingJDBC 由 ShardingSphere 组件家族中的 Sharding-JDBC 组件实现，它通过 JDBC 接口对应用程序透明化地进行数据分片和读写分离处理。ShardingJDBC 支持多种数据库类型，如 MySQL、PostgreSQL、SQL Server、Oracle 等，适用于各种分布式数据库场景。

ShardingJDBC的作用与应用场景

  1. 数据库分片：

    • 水平分片：将一张表的数据按某种规则拆分到多个物理表中，每个物理表单独存在，从而减轻单个数据库的压力。
    • 垂直分片：将表中的字段拆分到多个表中，通过字段的分离来提升数据库的读写性能。

  2. 读写分离：

    • 主从复制：将读操作分发到从库，减轻主库的压力。
    • 负载均衡：通过读写分离实现负载均衡，提高数据库系统的整体性能。
  3. 分布式事务：
    • 事务管理：通过分布式事务框架支持跨多个数据库的全局事务管理。

ShardingJDBC与其他分布式中间件的区别

  • 对比 MyCat 和 ShardingJDBC：

    • MyCat 是一个开源的分布式数据库中间件，可以实现读写分离和分库分表等功能。它通过代理层提供数据访问接口，可以整合多个数据库资源。
    • ShardingJDBC 是一个开源的分布式数据库中间件，主要专注于数据分片、读写分离等核心功能。相比于 MyCat，ShardingJDBC 更加轻量级，依赖较少，易于集成和维护。
  • 对比 ShardingSphere 和 ShardingJDBC：
    • ShardingSphere 是一个包含 Sharding-JDBC、Sharding-Proxy 和 Sharding-Sidecar 三个组件的分布式数据库中间件套件。其中，Sharding-JDBC 是 ShardingSphere 的核心组件之一。
    • ShardingJDBC 是 ShardingSphere 的子项目，主要提供数据库分片、读写分离等功能。Sharding-Proxy 是 ShardingSphere 的另一个组件，提供了一个数据库代理层，可以将请求分发到不同的数据库实例；Sharding-Sidecar 则是提供了一个独立部署的容器，用于实现数据库的动态分片和分库分表。
ShardingJDBC的核心功能

数据分片

数据分片是 ShardingJDBC 的核心功能之一，通过将数据水平拆分到多个物理表中，实现数据的水平分片。

示例代码:

import org.apache.shardingsphere.api.config.sharding.KeyGeneratorRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingStrategyConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingRuleConfigurationBuilder;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

public class ShardingDataExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 数据操作示例
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50))");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }
}

读写分离

读写分离是指将读操作和写操作分别分发到不同的数据库实例中，从而减轻主库的压力。ShardingJDBC 支持多种读写分离策略，包括主从复制和负载均衡。

示例代码:

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

public class ReadWriteSplittingExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 数据操作示例
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50))");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());

        // 创建读写分离配置
        shardingRuleConfig.getMasterSlaveRuleConfigurations().add(createMasterSlaveRuleConfiguration());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }

    private static StrategyConfiguration createMasterSlaveRuleConfiguration() {
        Properties properties = new Properties();
        properties.setProperty("master-data-source-name", "ds_0");
        properties.setProperty("slave-data-source-names", "ds_1");
        return new StandardShardingAlgorithm("master-slave-inline", properties);
    }
}

数据加密

ShardingJDBC 提供了内置的数据加密功能，可以对敏感数据进行加密存储，保证数据的安全性。

示例代码:

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

public class DataEncryptionExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 创建表
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50), encrypted_data VARCHAR(255))");

            // 插入加密数据
            insertEncryptedData(connection, 1, 1000);
            insertEncryptedData(connection, 2, 2000);

            // 查询加密数据
            selectEncryptedData(connection, 1);
            selectEncryptedData(connection, 2);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static void insertEncryptedData(Connection connection, int userId, int orderId) throws SQLException {
        String sql = "INSERT INTO t_order (order_id, user_id, status, encrypted_data) VALUES (?, ?, ?, ?)";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, orderId);
            preparedStatement.setInt(2, userId);
            preparedStatement.setString(3, "NEW");
            preparedStatement.setString(4, encryptData("123456"));
            preparedStatement.executeUpdate();
        }
    }

    private static void selectEncryptedData(Connection connection, int userId) throws SQLException {
        String sql = "SELECT * FROM t_order WHERE user_id = ?";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, userId);
            try (ResultSet resultSet = preparedStatement.executeQuery()) {
                while (resultSet.next()) {
                    System.out.println(resultSet.getInt("order_id"));
                    System.out.println(resultSet.getInt("user_id"));
                    System.out.println(resultSet.getString("status"));
                    System.out.println(decryptData(resultSet.getString("encrypted_data")));
                }
            }
        }
    }

    private static String encryptData(String data) {
        // 实际加密逻辑
        return "ENCRYPTED_" + data;
    }

    private static String decryptData(String encryptedData) {
        // 实际解密逻辑
        return encryptedData.substring("ENCRYPTED_".length());
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }
}

自定义策略

ShardingJDBC 支持自定义数据分片策略，用户可以根据自己的业务需求编写数据分片策略，实现更灵活的数据分片。

示例代码:

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

public class CustomShardingStrategyExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 数据操作示例
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50))");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());
        shardingRuleConfig.setShardingStrategyFactory(createShardingStrategyFactory());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }

    private static StrategyConfiguration createShardingStrategyFactory() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "custom_strategy");
        return new StandardShardingAlgorithm("custom_strategy", properties);
    }
}

动态数据源切换

ShardingJDBC 支持动态数据源切换，可以根据不同的业务场景或请求类型动态切换数据源，提高系统的灵活性和可扩展性。

ShardingJDBC的基本使用

ShardingJDBC的环境搭建

  1. 依赖引入：

    • 在 Maven 项目中，可以通过添加 ShardingJDBC 的依赖来引入 ShardingJDBC。

      <dependency>
 <groupId>org.apache.shardingsphere</groupId>
 <artifactId>sharding-jdbc-core-spi</artifactId>
 <version>4.1.1</version>
</dependency>

<dependency>
 <groupId>org.apache.shardingsphere</groupId>
 <artifactId>sharding-jdbc-spi</artifactId>
 <version>4.1.1</version>
</dependency>

<dependency>
 <groupId>org.apache.shardingsphere</groupId>
 <artifactId>sharding-jdbc-core</artifactId>
 <version>4.1.1</version>
</dependency>
  2. 数据库配置：
    • 配置多个数据库连接，例如 MySQL、PostgreSQL 等。

ShardingJDBC的基本配置

  1. ShardingRuleConfiguration：

    • 配置数据分片规则，包括表规则、分片策略等。
  2. DataSource：
    • 创建多个数据源实例，分别对应不同的物理数据库。

ShardingJDBC的数据分片规则配置

配置数据分片规则时，通常需要创建 ShardingRuleConfiguration 对象，并指定表规则、分片策略等信息。

示例代码:

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

public class ShardingRuleExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 数据操作示例
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50))");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }
}

ShardingJDBC的数据操作示例

在数据操作示例中，可以创建表、插入数据、查询数据等。

示例代码:

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

public class ShardingDataOperationExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 创建表
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50))");

            // 插入数据
            insertData(connection, 1, 1000);
            insertData(connection, 2, 2000);

            // 查询数据
            queryData(connection, 1);
            queryData(connection, 2);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static void insertData(Connection connection, int userId, int orderId) throws SQLException {
        String sql = "INSERT INTO t_order (order_id, user_id, status) VALUES (?, ?, ?)";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, orderId);
            preparedStatement.setInt(2, userId);
            preparedStatement.setString(3, "NEW");
            preparedStatement.executeUpdate();
        }
    }

    private static void queryData(Connection connection, int userId) throws SQLException {
        String sql = "SELECT * FROM t_order WHERE user_id = ?";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, userId);
            try (ResultSet resultSet = preparedStatement.executeQuery()) {
                while (resultSet.next()) {
                    System.out.println(resultSet.getInt("order_id"));
                    System.out.println(resultSet.getInt("user_id"));
                    System.out.println(resultSet.getString("status"));
                }
            }
        }
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }
}
ShardingJDBC的进阶使用

ShardingJDBC的SQL解析与执行

ShardingJDBC 的 SQL 解析与执行模块负责将业务 SQL 转换为多个分片 SQL，并发送到相应的数据库实例执行。

示例代码:

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

public class SQLParsingExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 创建表
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50))");

            // 插入数据
            insertData(connection, 1, 1000);
            insertData(connection, 2, 2000);

            // 查询数据
            queryData(connection, 1);
            queryData(connection, 2);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static void insertData(Connection connection, int userId, int orderId) throws SQLException {
        String sql = "INSERT INTO t_order (order_id, user_id, status) VALUES (?, ?, ?)";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, orderId);
            preparedStatement.setInt(2, userId);
            preparedStatement.setString(3, "NEW");
            preparedStatement.executeUpdate();
        }
    }

    private static void queryData(Connection connection, int userId) throws SQLException {
        String sql = "SELECT * FROM t_order WHERE user_id = ?";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, userId);
            try (ResultSet resultSet = preparedStatement.executeQuery()) {
                while (resultSet.next()) {
                    System.out.println(resultSet.getInt("order_id"));
                    System.out.println(resultSet.getInt("user_id"));
                    System.out.println(resultSet.getString("status"));
                }
            }
        }
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }
}

ShardingJDBC的事务管理

ShardingJDBC 提供了分布式事务管理，支持跨多个数据库实例的事务管理。

示例代码:

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

public class TransactionManagementExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 开始事务
            connection.setAutoCommit(false);

            // 创建表
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50))");

            // 插入数据
            insertData(connection, 1, 1000);
            insertData(connection, 2, 2000);

            // 提交事务
            connection.commit();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static void insertData(Connection connection, int userId, int orderId) throws SQLException {
        String sql = "INSERT INTO t_order (order_id, user_id, status) VALUES (?, ?, ?)";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, orderId);
            preparedStatement.setInt(2, userId);
            preparedStatement.setString(3, "NEW");
            preparedStatement.executeUpdate();
        }
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }
}

ShardingJDBC的日志与监控

ShardingJDBC 提供了日志与监控功能，可以帮助用户更好地了解数据分片和读写分离的实际运行情况。

示例代码:

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

public class LoggingAndMonitoringExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 创建表
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50))");

            // 插入数据
            insertData(connection, 1, 1000);
            insertData(connection, 2, 2000);

            // 查询数据
            queryData(connection, 1);
            queryData(connection, 2);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static void insertData(Connection connection, int userId, int orderId) throws SQLException {
        String sql = "INSERT INTO t_order (order_id, user_id, status) VALUES (?, ?, ?)";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, orderId);
            preparedStatement.setInt(2, userId);
            preparedStatement.setString(3, "NEW");
            preparedStatement.executeUpdate();
        }
    }

    private static void queryData(Connection connection, int userId) throws SQLException {
        String sql = "SELECT * FROM t_order WHERE user_id = ?";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, userId);
            try (ResultSet resultSet = preparedStatement.executeQuery()) {
                while (resultSet.next()) {
                    System.out.println(resultSet.getInt("order_id"));
                    System.out.println(resultSet.getInt("user_id"));
                    System.out.println(resultSet.getString("status"));
                }
            }
        }
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }
}
ShardingJDBC项目实战

ShardingJDBC在实际项目中的应用案例分析

在实际项目中，ShardingJDBC 可以用于应对大规模数据的处理和存储，提高系统的扩展性和性能。

示例代码:

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

public class RealProjectExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 创建表
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50))");

            // 插入数据
            insertData(connection, 1, 1000);
            insertData(connection, 2, 2000);

            // 查询数据
            queryData(connection, 1);
            queryData(connection, 2);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static void insertData(Connection connection, int userId, int orderId) throws SQLException {
        String sql = "INSERT INTO t_order (order_id, user_id, status) VALUES (?, ?, ?)";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, orderId);
            preparedStatement.setInt(2, userId);
            preparedStatement.setString(3, "NEW");
            preparedStatement.executeUpdate();
        }
    }

    private static void queryData(Connection connection, int userId) throws SQLException {
        String sql = "SELECT * FROM t_order WHERE user_id = ?";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, userId);
            try (ResultSet resultSet = preparedStatement.executeQuery()) {
                while (resultSet.next()) {
                    System.out.println(resultSet.getInt("order_id"));
                    System.out.println(resultSet.getInt("user_id"));
                    System.out.println(resultSet.getString("status"));
                }
            }
        }
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }
}

ShardingJDBC项目部署与运维

ShardingJDBC 的部署与运维主要包括以下几个步骤：

  1. 环境准备：

    • 安装 Java 和 Maven 环境。
    • 配置数据库连接信息。

  2. 项目构建：

    • 使用 Maven 构建项目，并引入 ShardingJDBC 依赖。
    • 配置 ShardingRuleConfiguration，设置数据分片规则。

  3. 启动服务：

    • 启动应用服务器，加载数据源配置和 ShardingRuleConfiguration。
  4. 监控与维护：
    • 使用监控工具监控数据库性能和系统运行状态。
    • 定期备份数据，确保数据安全。

示例代码:

import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
import org.apache.shardingsphere.api.config.sharding.strategy.StandardShardingAlgorithm;
import org.apache.shardingsphere.api.config.sharding.strategy.StrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.config.ShardingDataSourceFactory;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

public class DeploymentAndMaintenanceExample {

    public static void main(String[] args) {
        DataSource dataSource = createDataSource();
        try (Connection connection = dataSource.getConnection()) {
            // 创建表
            connection.createStatement().execute("CREATE TABLE t_order (order_id INT PRIMARY KEY, user_id INT, status VARCHAR(50))");

            // 插入数据
            insertData(connection, 1, 1000);
            insertData(connection, 2, 2000);

            // 查询数据
            queryData(connection, 1);
            queryData(connection, 2);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static void insertData(Connection connection, int userId, int orderId) throws SQLException {
        String sql = "INSERT INTO t_order (order_id, user_id, status) VALUES (?, ?, ?)";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, orderId);
            preparedStatement.setInt(2, userId);
            preparedStatement.setString(3, "NEW");
            preparedStatement.executeUpdate();
        }
    }

    private static void queryData(Connection connection, int userId) throws SQLException {
        String sql = "SELECT * FROM t_order WHERE user_id = ?";
        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
            preparedStatement.setInt(1, userId);
            try (ResultSet resultSet = preparedStatement.executeQuery()) {
                while (resultSet.next()) {
                    System.out.println(resultSet.getInt("order_id"));
                    System.out.println(resultSet.getInt("user_id"));
                    System.out.println(resultSet.getString("status"));
                }
            }
        }
    }

    private static DataSource createDataSource() {
        // 创建数据源
        DataSource dataSource = getDataSource();

        // 创建 ShardingRuleConfiguration
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTables().add(createTableRuleConfiguration("t_order"));
        shardingRuleConfig.setDefaultDatabaseShardingStrategy(createDatabaseShardingStrategy());
        shardingRuleConfig.setDefaultTableShardingStrategy(createTableShardingStrategy());

        // 构建 ShardingDataSource
        return ShardingDataSourceFactory.createDataSource(dataSource, shardingRuleConfig);
    }

    private static DataSource getDataSource() {
        // 实际项目中需要配置具体的数据库连接，这里仅为示例
        return null;
    }

    private static TableRuleConfiguration createTableRuleConfiguration(String logicTable) {
        TableRuleConfiguration tableRuleConfig = new TableRuleConfiguration(logicTable);
        tableRuleConfig.setDatabaseShardingStrategyConfig(createDatabaseShardingStrategy());
        tableRuleConfig.setTableShardingStrategyConfig(createTableShardingStrategy());
        return tableRuleConfig;
    }

    private static StrategyConfiguration createDatabaseShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "ds_${user_id % 2}");
        return new StandardShardingAlgorithm("database_inline", properties);
    }

    private static StrategyConfiguration createTableShardingStrategy() {
        Properties properties = new Properties();
        properties.setProperty("algorithm-expression", "t_order_${order_id % 2}");
        return new StandardShardingAlgorithm("table_inline", properties);
    }
}

ShardingJDBC常见问题及解决方法

  1. 性能问题：

    • 问题：数据量过大时，查询性能下降。
    • 解决方法：优化分片策略，合理分配数据；使用缓存提高查询效率。

  2. 数据一致性问题：

    • 问题：跨多个数据库的事务数据一致性难以保证。
    • 解决方法：使用分布式事务管理工具，确保跨库事务的一致性。

  3. 扩展问题：

    • 问题：系统扩展时，需要调整数据分片策略。
    • 解决方法：提供灵活的数据分片策略，支持动态调整。
  4. 维护问题：
    • 问题：维护过程中，数据迁移和备份困难。
    • 解决方法：使用数据迁移工具，确保数据迁移和备份的顺利进行。

总结，ShardingJDBC 是一个强大的分布式数据库中间件，通过透明化地进行数据分片和读写分离处理，大大简化了分布式数据库的使用。通过实际项目中的应用案例分析，可以更好地了解 ShardingJDBC 的实际应用场景和使用方法。同时，项目部署与运维也是保证系统稳定运行的重要环节。

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