Spring Boot入門教程(四十四): Sharding-JDBC+JPA|MyBatis+Druid分庫分表實現

阿新 • • 發佈：2019-01-07

一：資料庫分片方案

客戶端代理：分片邏輯在應用端，封裝在jar包中，通過修改或者封裝JDBC層來實現。噹噹網的 Sharding-JDBC 、阿里的TDDL是兩種比較常用的實現。
中介軟體代理：在應用和資料中間加了一個代理層。分片邏輯統一維護在中介軟體服務中。我們現在談的 Mycat、360的Atlas、網易的DDB等等都是這種架構的實現

二：Sharding-JDBC

Sharding-JDBC是一個開源的適用於微服務的分散式資料訪問基礎類庫，它始終以雲原生的基礎開發套件為目標。

Sharding-JDBC定位為輕量級java框架，使用客戶端直連資料庫，以jar包形式提供服務，未使用中間層，無需額外部署，無其他依賴，DBA也無需改變原有的運維方式，可理解為增強版的JDBC驅動，舊程式碼遷移成本幾乎為零。

Sharding-JDBC完整的實現了分庫分表，讀寫分離和分散式主鍵功能，並初步實現了柔性事務。從2016年開源至今，在經歷了整體架構的數次精煉以及穩定性打磨後，如今它已積累了足夠的底蘊，相信可以成為開發者選擇技術元件時的一個參考。

分庫分表
- SQL解析功能完善，支援聚合，分組，排序，LIMIT，TOP等查詢，並且支援級聯表以及笛卡爾積的表查詢
- 支援內、外連線查詢
- 分片策略靈活，可支援=，BETWEEN，IN等多維度分片，也可支援多分片鍵共用，以及自定義分片策略
- 基於Hint的強制分庫分表路由
讀寫分離
- 一主多從的讀寫分離配置，可配合分庫分表使用
- 基於Hint的強制主庫路由
柔性事務
- 最大努力送達型事務
- TCC型事務(TBD)
分散式主鍵
- 統一的分散式基於時間序列的ID生成器
相容性
- 可適用於任何基於java的ORM框架，如：JPA, Hibernate, Mybatis, Spring JDBC Template或直接使用JDBC
- 可基於任何第三方的資料庫連線池，如：DBCP, C3P0, BoneCP, Druid等
- 理論上可支援任意實現JDBC規範的資料庫。目前支援MySQL，Oracle，SQLServer和PostgreSQL
靈活多樣的配置
- Java
- YAML
- Inline表示式
- Spring名稱空間
- Spring boot starter
分散式治理能力 (2.0新功能)
- 配置集中化與動態化，可支援資料來源、表與分片策略的動態切換(2.0.0.M1)
- 客戶端的資料庫治理，資料來源失效自動切換(2.0.0.M2)
- 基於Open Tracing協議的APM資訊輸出(2.0.0.M3)

架構圖
這裡寫圖片描述

三：sharding-jdbc + jpa + druid整合

這裡寫圖片描述

0. 資料庫

-- 在db0資料庫上分別建立t_order_0、t_order_1表
USE db0;
DROP TABLE IF EXISTS t_order_0; 
CREATE TABLE t_order_0 ( 
order_id bigint(20) NOT NULL, 
user_id bigint(20) NOT NULL, 
PRIMARY KEY (order_id) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 
DROP TABLE IF EXISTS t_order_1; 
CREATE TABLE t_order_1 ( 
order_id bigint(20) NOT NULL, 
user_id bigint(20) NOT NULL, 
PRIMARY KEY (order_id) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 


-- 在db1資料庫上分別建立t_order_0、t_order_1表
USE db1;
DROP TABLE IF EXISTS t_order_0; 
CREATE TABLE t_order_0 ( 
order_id bigint(20) NOT NULL, 
user_id bigint(20) NOT NULL, 
PRIMARY KEY (order_id) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 

DROP TABLE IF EXISTS t_order_1; 
CREATE TABLE t_order_1 ( 
order_id bigint(20) NOT NULL, 
user_id bigint(20) NOT NULL, 
PRIMARY KEY (order_id) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

1. 引入依賴

<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.company</groupId>
    <artifactId>sharding-jdbc</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>sharding-jdbc</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.41</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.10</version>
        </dependency>

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

        <dependency>
            <groupId>com.dangdang</groupId>
            <artifactId>sharding-jdbc-core</artifactId>
            <version>1.5.4</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

注意mysql-connector-java的版本不要太高了

2. application.yml

spring:
  jpa:
    database: mysql
    show-sql: true
    hibernate:
      ddl-auto: none

注意：hibernate.ddl-auto=none 是因為分表就會有多個表，例如t_order_0、t_order_1等，而ORM只能對映成一個，所以關閉自動的ddl語句。

3. domain

@Entity
@Table(name = "t_order")
@Data
public class Order {
    @Id
    private Long orderId;

    private Long userId;
}

注意：orderId上使用@Id註解並沒有使用@GeneratedValue(strategy = GenerationType.AUTO)的主鍵生成策略，原因是分表必須要保證所有表的主鍵id不重複，如果使用mysql的自動生成，那麼id就會重複，這裡的id一般要使用分散式主鍵id來通過程式碼來生成。

4. Repository

import com.company.shardingjdbc.domain.Order;
import org.springframework.data.repository.CrudRepository;

public interface OrderRepository extends CrudRepository<Order, Long> {
}

5. Controller

import com.company.shardingjdbc.domain.Order;
import com.company.shardingjdbc.repository.OrderRepository;
import com.dangdang.ddframe.rdb.sharding.keygen.KeyGenerator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/order")
public class OrderController {

    @Autowired
    private OrderRepository orderRepository;

    @Autowired
    private KeyGenerator keyGenerator;

    @RequestMapping("/create")
    public Object add() {
        for (int i = 0; i < 10; i++) {
            Order order = new Order();
            order.setUserId((long) i);
            order.setOrderId((long) i);
            orderRepository.save(order);
        }
        for (int i = 10; i < 20; i++) {
            Order order = new Order();
            order.setUserId((long) i + 1);
            order.setOrderId((long) i);
            orderRepository.save(order);
        }

//        for (int i = 0; i < 30; i++) {
//            Order order = new Order();
//            order.setOrderId(keyGenerator.generateKey().longValue());
//            order.setUserId(keyGenerator.generateKey().longValue());
//            orderRepository.save(order);
//        }

        return "success";
    }

    @RequestMapping("query")
    private Object queryAll() {
        return orderRepository.findAll();
    }
}

6. Configuration

package com.company.shardingjdbc.configuration;

import com.alibaba.druid.pool.DruidDataSource;
import com.company.shardingjdbc.common.ModuleDatabaseShardingAlgorithm;
import com.company.shardingjdbc.common.ModuleTableShardingAlgorithm;
import com.dangdang.ddframe.rdb.sharding.api.ShardingDataSourceFactory;
import com.dangdang.ddframe.rdb.sharding.api.rule.DataSourceRule;
import com.dangdang.ddframe.rdb.sharding.api.rule.ShardingRule;
import com.dangdang.ddframe.rdb.sharding.api.rule.TableRule;
import com.dangdang.ddframe.rdb.sharding.api.strategy.database.DatabaseShardingStrategy;
import com.dangdang.ddframe.rdb.sharding.api.strategy.table.TableShardingStrategy;
import com.dangdang.ddframe.rdb.sharding.keygen.DefaultKeyGenerator;
import com.dangdang.ddframe.rdb.sharding.keygen.KeyGenerator;
import com.mysql.jdbc.Driver;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;


@Configuration
public class DataSourceConfiguration {
    @Bean
    public DataSource getDataSource() throws SQLException {
        return buildDataSource();
    }

    private DataSource buildDataSource() throws SQLException {
        // 設定分庫對映
        Map<String, DataSource> dataSourceMap = new HashMap<>(2);
        // 新增兩個資料庫db0,db1到map裡
        dataSourceMap.put("db0", createDataSource("db0"));
        dataSourceMap.put("db1", createDataSource("db1"));
        // 設定預設db為db0，也就是為那些沒有配置分庫分表策略的指定的預設庫
        // 如果只有一個庫，也就是不需要分庫的話，map裡只放一個對映就行了，只有一個庫時不需要指定預設庫，但2個及以上時必須指定預設庫，否則那些沒有配置策略的表將無法操作資料
        DataSourceRule dataSourceRule = new DataSourceRule(dataSourceMap, "db0");

        // 設定分表對映，將t_order_0和t_order_1兩個實際的表對映到t_order邏輯表
        // 0和1兩個表是真實的表，t_order是個虛擬不存在的表，只是供使用。如查詢所有資料就是select * from t_order就能查完0和1表的
        TableRule orderTableRule = TableRule.builder("t_order")
                .actualTables(Arrays.asList("t_order_0", "t_order_1"))
                .dataSourceRule(dataSourceRule)
                .build();

        // 具體分庫分表策略，按什麼規則來分
        ShardingRule shardingRule = ShardingRule.builder()
                .dataSourceRule(dataSourceRule)
                .tableRules(Arrays.asList(orderTableRule))
                .databaseShardingStrategy(new DatabaseShardingStrategy("user_id", new ModuleDatabaseShardingAlgorithm()))
                .tableShardingStrategy(new TableShardingStrategy("order_id", new ModuleTableShardingAlgorithm())).build();

        DataSource dataSource = ShardingDataSourceFactory.createDataSource(shardingRule);

        return dataSource;
    }

    private static DataSource createDataSource(final String dataSourceName) {
        // 使用druid連線資料庫
        DruidDataSource result = new DruidDataSource();
        result.setDriverClassName(Driver.class.getName());
        result.setUrl(String.format("jdbc:mysql://localhost:3306/%s", dataSourceName));
        result.setUsername("root");
        result.setPassword("root123");
        return result;
    }

    @Bean
    public KeyGenerator keyGenerator() {
        return new DefaultKeyGenerator();
    }
}

ModuleDatabaseShardingAlgorithm

package com.company.shardingjdbc.common;

import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.database.SingleKeyDatabaseShardingAlgorithm;
import com.google.common.collect.Range;

import java.util.Collection;
import java.util.LinkedHashSet;

/**
 * 單鍵資料庫分片演算法.
 *
 * 支援單鍵和多鍵策略
 * <ul>
 *     <li>單鍵 SingleKeyDatabaseShardingAlgorithm</li>
 *     <li>多鍵 MultipleKeysDatabaseShardingAlgorithm</li>
 * </ul>
 *
 * 支援的分片策略
 * <ul>
 *     <li> = doEqualSharding 例如 where order_id = 1 </li>
 *     <li> IN doInSharding 例如 where order_id in (1, 2)</li>
 *     <li> BETWEEN doBetweenSharding 例如 where order_id between 1 and 2 </li>
 * </ul>
 *
 * @author mengday
 */
public class ModuleDatabaseShardingAlgorithm implements SingleKeyDatabaseShardingAlgorithm<Long> {

    /**
     * 分片策略 相等=
     * @param availableTargetNames 可用的目標名字(這裡指資料名db0、db1)
     * @param shardingValue 分片值[logicTableName="t_order" 邏輯表名, columnName="user_id" 分片的列名, value="20" 分片的列名對應的值(user_id=20)]
     * @return
     */
    @Override
    public String doEqualSharding(Collection<String> availableTargetNames, ShardingValue<Long> shardingValue) {
        for (String each : availableTargetNames) {
            if (each.endsWith(shardingValue.getValue() % 2 + "")) {
                return each;
            }
        }
        throw new IllegalArgumentException();
    }

    @Override
    public Collection<String> doInSharding(Collection<String> availableTargetNames, ShardingValue<Long> shardingValue) {
        Collection<String> result = new LinkedHashSet<>(availableTargetNames.size());
        for (Long value : shardingValue.getValues()) {
            for (String tableName : availableTargetNames) {
                if (tableName.endsWith(value % 2 + "")) {
                    result.add(tableName);
                }
            }
        }
        return result;
    }

    @Override
    public Collection<String> doBetweenSharding(Collection<String> availableTargetNames,
                                                ShardingValue<Long> shardingValue) {
        Collection<String> result = new LinkedHashSet<>(availableTargetNames.size());
        Range<Long> range = shardingValue.getValueRange();
        for (Long i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
            for (String each : availableTargetNames) {
                if (each.endsWith(i % 2 + "")) {
                    result.add(each);
                }
            }
        }
        return result;
    }
}

package com.company.shardingjdbc.common;

import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.table.SingleKeyTableShardingAlgorithm;
import com.google.common.collect.Range;

import java.util.Collection;
import java.util.LinkedHashSet;

public final class ModuleTableShardingAlgorithm implements SingleKeyTableShardingAlgorithm<Long> {

    /**
     * doEqualSharding =
     * @param tableNames 實際物理表名
     * @param shardingValue [logicTableName="t_order", columnName="order_id", value=20]
     * 
     *  select * from t_order from t_order where order_id = 11
     *          └── SELECT *  FROM t_order_1 WHERE order_id = 11
     *  select * from t_order from t_order where order_id = 44
     *          └── SELECT *  FROM t_order_0 WHERE order_id = 44
     */
     *  select * from t_order from t_order where order_id = 11
     *          └── SELECT *  FROM t_order_1 WHERE order_id = 11
     *  select * from t_order from t_order where order_id = 44
     *          └── SELECT *  FROM t_order_0 WHERE order_id = 44
     */
    public String doEqualSharding(final Collection<String> tableNames, final ShardingValue<Long> shardingValue) {
        for (String each : tableNames) {
            if (each.endsWith(shardingValue.getValue() % 2 + "")) {
                return each;
            }
        }
        throw new IllegalArgumentException();
    }

    /**
     *  select * from t_order from t_order where order_id in (11,44)
     *          ├── SELECT *  FROM t_order_0 WHERE order_id IN (11,44)
     *          └── SELECT *  FROM t_order_1 WHERE order_id IN (11,44)
     *  select * from t_order from t_order where order_id in (11,13,15)
     *          └── SELECT *  FROM t_order_1 WHERE order_id IN (11,13,15)
     *  select * from t_order from t_order where order_id in (22,24,26)
     *          └──SELECT *  FROM t_order_0 WHERE order_id IN (22,24,26)
     */
    public Collection<String> doInSharding(final Collection<String> tableNames, final ShardingValue<Long> shardingValue) {
        Collection<String> result = new LinkedHashSet<>(tableNames.size());
        for (Long value : shardingValue.getValues()) {
            for (String tableName : tableNames) {
                if (tableName.endsWith(value % 2 + "")) {
                    result.add(tableName);
                }
            }
        }
        return result;
    }
    /**
     *  select * from t_order from t_order where order_id between 10 and 20
     *          ├── SELECT *  FROM t_order_0 WHERE order_id BETWEEN 10 AND 20
     *          └── SELECT *  FROM t_order_1 WHERE order_id BETWEEN 10 AND 20
     */
    public Collection<String> doBetweenSharding(final Collection<String> tableNames, final ShardingValue<Long> shardingValue) {
        Collection<String> result = new LinkedHashSet<>(tableNames.size());
        Range<Long> range = shardingValue.getValueRange();
        for (Long i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
            for (String each : tableNames) {
                if (each.endsWith(i % 2 + "")) {
                    result.add(each);
                }
            }
        }
        return result;
    }
}

7. localhost:8080/order/create

db0
├── t_order_0 user_id為偶數 order_id為偶數
├── t_order_1 user_id為偶數 order_id為奇數
db1
├── t_order_0 user_id為奇數 order_id為偶數
├── t_order_1 user_id為奇數 order_id為奇數

這裡寫圖片描述

四：sharding-jdbc + mybatis + druid整合

此示例是在jap原有的整合上整合mybatis

1. 引入mybatis依賴

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>

2. 在Application上添加註解@MapperScan

@MapperScan("com.company.shardingjdbc.mapper")
@SpringBootApplication
public class ShardingJdbcApplication {

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

3. application.yml

# Mybatis 配置
mybatis:
  typeAliasesPackage: com.company.shardingjdbc.domain
  mapperLocations: classpath:mapper/*.xml
  configuration.map-underscore-to-camel-case: true

# 列印mybatis中的sql語句和結果集
logging:
  level.com.company.shardingjdbc.mapper: TRACE

4. OrderMapper

import org.apache.ibatis.annotations.Param;

import java.util.List;

public interface OrderMapper {

    void insert(Order order);

    List<Order> queryById(@Param("orderIdList") List<Long> orderIdList);
}

5. OrderMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.company.shardingjdbc.mapper.OrderMapper" >
    <select id="queryById" parameterType="Long" resultType="Order">
        SELECT * FROM t_order WHERE order_id IN
        <foreach collection="orderIdList" item="orderId" open="(" separator="," close=")">
            #{orderId}
        </foreach>
    </select>

    <insert id="insert" parameterType="Order">
        INSERT INTO t_order (order_id, user_id) VALUES (#{orderId}, #{userId})
    </insert>
</mapper>

6. OrderController

import com.dangdang.ddframe.rdb.sharding.keygen.KeyGenerator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

@RestController
@RequestMapping("/order")
public class OrderController {

    @Autowired
    private OrderMapper orderMapper;

    @RequestMapping("/insert")
    public Object insert() {
        for (int i = 20; i < 30; i++) {
            Order order = new Order();
            order.setUserId((long) i);
            order.setOrderId((long) i);
            orderMapper.insert(order);
        }
        for (int i = 30; i < 40; i++) {
            Order order = new Order();
            order.setUserId((long) i + 1);
            order.setOrderId((long) i);
            orderMapper.insert(order);
        }

        return "success";
    }

    @RequestMapping("queryById")
    public List<Order> queryById(String orderIds) {
        List<String> strings = Arrays.asList(orderIds.split(","));
        List<Long> orderIdList = strings.stream().map(item -> Long.parseLong(item)).collect(Collectors.toList());
        return orderMapper.queryById(orderIdList);
    }
}

7. 插入資料

localhost:8080/order/insert

這裡寫圖片描述

ModuleDatabaseShardingAlgorithm: 先根據分片鍵user_id及值來確定要操作的資料庫是db0還是db1
ModuleTableShardingAlgorithm: 再根據分片鍵order_id及值來確定要操作的資料庫對應的表是t_order_0還是t_order_1
當資料庫名和表名都確定了就可以操作資料庫了

這裡寫圖片描述

localhost:8080/order/queryById?orderIds=20,31,30,21
這裡寫圖片描述

Spring Boot入門教程(四十四): Sharding-JDBC+JPA|MyBatis+Druid分庫分表實現

一：資料庫分片方案

二：Sharding-JDBC

三：sharding-jdbc + jpa + druid整合

0. 資料庫

1. 引入依賴

2. application.yml

3. domain

4. Repository

5. Controller

6. Configuration

7. localhost:8080/order/create

四：sharding-jdbc + mybatis + druid整合

1. 引入mybatis依賴

2. 在Application上添加註解@MapperScan

3. application.yml

4. OrderMapper

5. OrderMapper.xml

6. OrderController

7. 插入資料

五：示例原始碼下載

相關推薦