一.前言
这是一个基于 SpringBoot 整合 Sharding-JDBC 实现读写分离的极简教程,笔者使用到的技术及版本如下:
SpringBoot 2.5.2
MyBatis-Plus 3.4.3
Sharding-JDBC 4.1.1
MySQL8 集群(看笔者前一篇文章有部署教程)
二.项目目录结构
三.pom 文件
<?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>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.5.2</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>xyz.hcworld</groupId>
<artifactId>sharding-jdbc-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>sharding-jdbc-demo</name>
<description>多数据源切换实例</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- mybatis-plus依赖 -->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.4.3</version>
</dependency>
<!-- mysql驱动 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!-- sharding-jdbc(多数据源切换) -->
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-boot-starter</artifactId>
<version>4.1.1</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.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludes>
<exclude>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
</build>
</project>
四.配置文件(基于 YAML)及 SQL 建表语句
spring:
main:
allow-bean-definition-overriding: true
#显示sql
shardingsphere:
props:
sql:
show: true
masterslave:
#配置主从名称
name: ms
#置主库master,负责数据的写入
master-data-source-name: ds1
#配置从库slave节点
slave-data-source-names: ds2,ds3
#配置slave节点的负载均衡均衡策略,采用轮询机制,有两种算法:round_robin(轮询)和random(随机)
load-balance-algorithm-type: round_robin
sharding:
#配置默认数据源ds1 默认数据源,主要用于写
default-data-source-name: ds1
# 配置数据源
datasource:
names: ds1,ds2,ds3
#master-ds1数据库连接信息
ds1:
type: com.zaxxer.hikari.HikariDataSource
driver-class-name: com.mysql.cj.jdbc.Driver
jdbc-url: jdbc:mysql://192.168.2.142:3307/sharding-jdbc-db?useUnicode=true&useSSL=false&serverTimezone=Asia/Shanghai
username: root
password: 123456
maxPoolSize: 100
minPoolSize: 5
#slave-ds2数据库连接信息
ds2:
type: com.zaxxer.hikari.HikariDataSource
driver-class-name: com.mysql.cj.jdbc.Driver
jdbc-url: jdbc:mysql://192.168.2.142:3308/sharding-jdbc-db?useUnicode=true&useSSL=false&serverTimezone=Asia/Shanghai
username: root
password: 123456
maxPoolSize: 100
minPoolSize: 5
#slave-ds3数据库连接信息
ds3:
type: com.zaxxer.hikari.HikariDataSource
driver-class-name: com.mysql.cj.jdbc.Driver
jdbc-url: jdbc:mysql://192.168.2.142:3309/sharding-jdbc-db?useUnicode=true&useSSL=false&serverTimezone=Asia/Shanghai
username: root
password: 123456
maxPoolSize: 100
minPoolSize: 5
#mybatis-plus配置
mybatis-plus:
type-aliases-package: xyz.hcworld.demo.model
mapper-locations: classpath*:/mapper/**Mapper.xml
CREATE TABLE `t_user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`nickname` varchar(100) DEFAULT NULL,
`password` varchar(100) DEFAULT NULL,
`sex` int(11) DEFAULT NULL,
`birthday` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;
五.Mapper.xml 文件及 Mapper 接口
<?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="xyz.hcworld.demo.mapper.UserMapper">
<update id="addUser">
INSERT INTO t_user(nickname,PASSWORD,sex,birthday) VALUES(#{nickname},#{password},#{sex},#{birthday})
</update>
<select id="findUsers" resultType="xyz.hcworld.demo.model.User">
SELECT
id,
nickname,
PASSWORD,
sex,
birthday
FROM t_user;
</select>
</mapper>
package xyz.hcworld.demo.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.springframework.stereotype.Component;
import xyz.hcworld.demo.model.User;
import java.util.List;
/**
* @ClassName: UserMapper
* @Author: 张红尘
* @Date: 2021-07-20
* @Version: 1.0
*/
@Component
public interface UserMapper extends BaseMapper<User> {
void addUser(User user);
List<User> findUsers();
}
六 .Controller 及 Mocel 文件
package xyz.hcworld.demo.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import xyz.hcworld.demo.mapper.UserMapper;
import xyz.hcworld.demo.model.User;
import java.security.SecureRandom;
import java.util.List;
/**
* @ClassName: UserController
* @Author: 张红尘
* @Date: 2021-07-20
* @Version: 1.0
*/
@RestController
@RequestMapping("/api/user")
public class UserController {
@Autowired
private UserMapper userMapper;
@PostMapping("/save")
public String addUser() {
User user = new User();
user.setNickname("zhangsan" + new SecureRandom().nextInt());
user.setPassword("123456");
user.setSex(1);
user.setBirthday("1997-12-03");
userMapper.addUser(user);
return user.toString();
}
@GetMapping("/findUsers")
public List<User> findUsers() {
return userMapper.findUsers();
}
}
package xyz.hcworld.demo.model;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
import lombok.EqualsAndHashCode;
/**
* @ClassName: User
* @Author: 张红尘
* @Date: 2021-07-20
* @Version: 1.0
*/
@Data
@TableName("t_user")
public class User {
private static final long serialVersionUID = 1L;
@TableId(value = "id", type = IdType.AUTO)
private Integer id;
private String nickname;
private String password;
private Integer sex;
private String birthday;
}
七.结果
从结果可以看出,写入操作全部通过 ds1 数据库(master)数据库完成,而读操作因为设置了轮询的缘故,由 ds2(slaver)、ds3(slaver2)数据库完成。这样就实现了基于一主二从的数据库集群的读写分离操作。
八.Sharding-JDBC 不同版本上的配置
网上 Sharding-JDBC 的教程多为 4.0.0.RC1 版本,笔者使用的是最新的 4.1.1 所以
在该部分数据库地址在 4.1.1 为 jdbc-url 在 4.0.0.RC1 上需要改为 url 否则会启动失败
jdbc-url: jdbc:mysql://XXXX/XXXX
且网上教程多为 properties 文件,笔者将其转变为 YAML 文件更加能直观感受
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