1 前言

shardingshpere-jdbc定位為輕量級 Java 框架，在 Java 的 JDBC 層提供的額外服務(wù)。 它使用客戶端直連數(shù)據(jù)庫，以 jar 包形式提供服務(wù)，無需額外部署和依賴，可理解為增強版的 JDBC 驅(qū)動，完全兼容 JDBC 和各種 ORM 框架。

關(guān)于mysql配置主從復(fù)制，可以參考之前寫的文章=0101docker mysql8鏡像主從復(fù)制-運維-mysql=

2、創(chuàng)建SpringBoot程序

2.1、創(chuàng)建項目

項目類型：Spring Initializr

SpringBoot腳手架：http://start.aliyun.com

項目名：sharding-jdbc-demo

SpringBoot版本：2.7.10

2.2、添加依賴

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.gaogzhen</groupId><artifactId>sharging-jdbc-demo</artifactId><version>0.0.1-SNAPSHOT</version><name>sharging-jdbc-demo</name><description>Demo project for Spring Boot</description><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.7.10</version><relativePath /></parent><properties><java.version>1.8</java.version><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><spring-boot.version>2.7.10</spring-boot.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.apache.shardingsphere</groupId><artifactId>shardingsphere-jdbc-core-spring-boot-starter</artifactId><version>5.1.1</version></dependency><dependency><groupId>com.mysql</groupId><artifactId>mysql-connector-j</artifactId></dependency><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.3.1</version></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.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><version>3.8.1</version><configuration><source>1.8</source><target>1.8</target><encoding>UTF-8</encoding></configuration></plugin><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><version>${spring-boot.version}</version><configuration><mainClass>com.gaogzhen.shardingjdbcdemo.ShardingJdbcDemoApplication</mainClass></configuration><executions><execution><id>repackage</id><goals><goal>repackage</goal></goals></execution></executions></plugin></plugins></build></project>

2.3、生成實體類、service與Mapper

使用idea插件mybatisX，根據(jù)數(shù)據(jù)庫連接表生成實體類、service、mapper

第一步：如下圖2.3-1所示

第二步：如下圖2.3-2所示:

• 實體類

package com.gaogzhen.shardingjdbcdemo.entity;import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import java.io.Serializable;
import lombok.Data;/*** 用戶* @author gaogzhen* @TableName t_user*/
@TableName(value ="t_user")
@Data
public class User implements Serializable {@TableField(exist = false)private static final long serialVersionUID = 1L;@TableId(type = IdType.AUTO)private Long id;/*** 用戶名*/private String name;}

• service

package com.gaogzhen.shardingjdbcdemo.service;import com.gaogzhen.shardingjdbcdemo.entity.User;
import com.baomidou.mybatisplus.extension.service.IService;/**
* @author gaogzhen
* @description 針對表【t_user】的數(shù)據(jù)庫操作Service
* @createDate 2023-08-13 15:37:14
*/
public interface UserService extends IService<User> {}

• serviceImpl

package com.gaogzhen.shardingjdbcdemo.service.impl;import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.gaogzhen.shardingjdbcdemo.entity.User;
import com.gaogzhen.shardingjdbcdemo.service.UserService;
import com.gaogzhen.shardingjdbcdemo.mapper.UserMapper;
import org.springframework.stereotype.Service;/**
* @author gaogzhen
* @description 針對表【t_user】的數(shù)據(jù)庫操作Service實現(xiàn)
* @createDate 2023-08-13 15:37:14
*/
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User>implements UserService{}

• mapper

package com.gaogzhen.shardingjdbcdemo.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.gaogzhen.shardingjdbcdemo.entity.User;
import org.apache.ibatis.annotations.Mapper;/**
* @author gaogzhen
* @description 針對表【t_user】的數(shù)據(jù)庫操作Mapper
* @createDate 2023-08-13 15:37:14
* @Entity com.gaogzhen.shardingjdbcdemo.entity.User
*/
@Mapper
public interface UserMapper extends BaseMapper<User> {}

1.5、配置讀寫分離

application.properties：

# 應(yīng)用名稱
spring.application.name=sharging-jdbc-demo
# 開發(fā)環(huán)境設(shè)置
spring.profiles.active=dev
# 內(nèi)存模式
spring.shardingsphere.mode.type=Memory# 配置真實數(shù)據(jù)源
spring.shardingsphere.datasource.names=master,slave1,slave2# 配置第 1 個數(shù)據(jù)源
spring.shardingsphere.datasource.master.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.master.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.master.jdbc-url=jdbc:mysql://127.0.0.1:3340/db_user?allowPublicKeyRetrieval=true&useSSL=false
spring.shardingsphere.datasource.master.username=root
spring.shardingsphere.datasource.master.password=123456# 配置第 2 個數(shù)據(jù)源
spring.shardingsphere.datasource.slave1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.slave1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.slave1.jdbc-url=jdbc:mysql://127.0.0.1:3341/db_user?allowPublicKeyRetrieval=true&useSSL=false
spring.shardingsphere.datasource.slave1.username=root
spring.shardingsphere.datasource.slave1.password=123456# 配置第 3 個數(shù)據(jù)源
spring.shardingsphere.datasource.slave2.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.slave2.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.slave2.jdbc-url=jdbc:mysql://127.0.0.1:3342/db_user?allowPublicKeyRetrieval=true&useSSL=false
spring.shardingsphere.datasource.slave2.username=root
spring.shardingsphere.datasource.slave2.password=123456# 讀寫分離類型，如: Static，Dynamic
spring.shardingsphere.rules.readwrite-splitting.data-sources.myds.type=Static
# 寫數(shù)據(jù)源名稱
spring.shardingsphere.rules.readwrite-splitting.data-sources.myds.props.write-data-source-name=master
# 讀數(shù)據(jù)源名稱，多個從數(shù)據(jù)源用逗號分隔
spring.shardingsphere.rules.readwrite-splitting.data-sources.myds.props.read-data-source-names=slave1,slave2# 負載均衡算法名稱
spring.shardingsphere.rules.readwrite-splitting.data-sources.myds.load-balancer-name=alg_round# 負載均衡算法配置
# 負載均衡算法類型
spring.shardingsphere.rules.readwrite-splitting.load-balancers.alg_round.type=ROUND_ROBIN
spring.shardingsphere.rules.readwrite-splitting.load-balancers.alg_random.type=RANDOM
spring.shardingsphere.rules.readwrite-splitting.load-balancers.alg_weight.type=WEIGHT
spring.shardingsphere.rules.readwrite-splitting.load-balancers.alg_weight.props.slave1=1
spring.shardingsphere.rules.readwrite-splitting.load-balancers.alg_weight.props.slave2=2# 打印SQl
spring.shardingsphere.props.sql-show=true# mybatis plus 配置
mybatis.mapper-locations=classpath:mapper/*.xml
mybatis.type-aliases-package=com.gaogzhen.shardingjdbcdemo.entity

• myds為自定義的邏輯數(shù)據(jù)源名稱
• 當(dāng)前生效的負載均衡算法為輪詢，可以通過更換負載均衡算法名稱，來測試隨機和權(quán)重。

2、測試

2.1、讀寫分離測試

package com.gaogzhen.shardingjdbcdemo;import com.gaogzhen.shardingjdbcdemo.entity.User;
import com.gaogzhen.shardingjdbcdemo.mapper.UserMapper;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.transaction.annotation.Transactional;import javax.annotation.Resource;
import java.util.List;@SpringBootTest
public class ReadWriteTest {@Resourceprivate UserMapper userMapper;/*** 讀寫分離：寫入數(shù)據(jù)的測試*/@Testpublic void testInsert(){User user = new User();user.setName("張三");userMapper.insert(user);User user1 = userMapper.selectById(1L);}}

2.2、事務(wù)測試

為了保證主從庫間的事務(wù)一致性，避免跨服務(wù)的分布式事務(wù)，ShardingSphere-JDBC的主從模型中，事務(wù)中的數(shù)據(jù)讀寫均用主庫。

• 不添加@Transactional：insert對主庫操作，select對從庫操作
• 添加@Transactional：則insert和select均對主庫操作
• **注意：**在JUnit環(huán)境下的@Transactional注解，默認情況下就會對事務(wù)進行回滾（即使在沒加注解@Rollback，也會對事務(wù)回滾）

 /*** 事務(wù)測試*/@Transactional@Testpublic void testTrans() {User user = new User();user.setName("xxx001");userMapper.insert(user);List<User> users = userMapper.selectList(null);}

2.3、負載均衡測試

/*** 負載均衡測試*/
@Test
public void testLoadBalance() {List<User> users1 = userMapper.selectList(null);List<User> users2 = userMapper.selectList(null);}

也可以在web請求中測試負載均衡

package com.gaogzhen.shardingjdbcdemo.controller;import com.gaogzhen.shardingjdbcdemo.entity.User;
import com.gaogzhen.shardingjdbcdemo.service.UserService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;
import java.util.List;@RestController
@RequestMapping("/user")
public class UserController {@Resourceprivate UserService userService;/*** 測試負載均衡策略*/@GetMapping("selectAll")public void selectAll(){List<User> users = userService.list();users.forEach(System.out::println);}
}

命令行測試結(jié)果如下圖所示：

結(jié)語

如果小伙伴什么問題或者指教，歡迎交流。

QQ:806797785

倉庫源代碼地址：https://github.com/gaogzhen/shardingsphere-jdbc-demo.git

參考鏈接:

[1]ShardingSphere5實戰(zhàn)教程[CP/OL].2022-09-14.p18-23.

[2]mysql官網(wǎng)使用配置文件文檔[CP/OL].