Java：SpringBoot整合Sharding-Jdbc实现数据库读写分离

读写分离实现效果：写操作使用master主库，读操作使用slave从库

依赖

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.5.2</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-jdbc-spring-boot-starter</artifactId>
    <version>4.0.0</version>
</dependency>

完整依赖 pom.xml

<?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>2.7.7</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.shardingsphere</groupId>
            <artifactId>sharding-jdbc-spring-boot-starter</artifactId>
            <version>4.0.0</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>

配置 application.yml

server:
  port: 8080

mybatis-plus:
  configuration:
    map-underscore-to-camel-case: true
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  global-config:
    db-config:
      id-type: AUTO

spring:
  shardingsphere:
    sharding:
      default-data-source-name: master
    props:
        sql:
          # 开启sql显示，默认false
          show: true
    datasource:
      names: master,slave1,slave2
      # 主库
      master:
        type: com.zaxxer.hikari.HikariDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        jdbc-url: jdbc:mysql://127.0.0.1:3306/data?useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8
        username: root
        password: 123456
      # 从库1
      slave1:
        type: com.zaxxer.hikari.HikariDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        jdbc-url: jdbc:mysql://127.0.0.1:3306/data?useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8
        username: root
        password: 123456
      # 从库2
      slave2:
        type: com.zaxxer.hikari.HikariDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        jdbc-url: jdbc:mysql://127.0.0.1:3306/data?useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8
        username: root
        password: 123456

    # 读写分离配置
    masterslave:
      # 从库负载均衡策略：轮询
      load-balance-algorithm-type: round_robin
      # 最终的数据源名称
      name: dataSource
      # 主库数据源名称
      master-data-source-name: master
      # 从库数据源名称，多个逗号分隔
      slave-data-source-names: slave1,slave2

建表语句

CREATE TABLE `user` (
  `id` int NOT NULL AUTO_INCREMENT,
  `name` varchar(20),
  `age` int DEFAULT 0,
  PRIMARY KEY (`id`)
)

实体类

package com.example.demo.entity;

import lombok.Data;

import java.io.Serializable;

@Data
public class User implements Serializable {
    private Long id;
    private String name;
    private Integer age;
}

Mapper

package com.example.demo.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo.entity.User;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface UserMapper extends BaseMapper<User> {
}

IService

package com.example.demo.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.example.demo.entity.User;

public interface UserService extends IService<User> {
}

ServiceImpl

package com.example.demo.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.demo.entity.User;
import com.example.demo.mapper.UserMapper;
import com.example.demo.service.UserService;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl
        extends ServiceImpl<UserMapper, User>
        implements UserService {
}

Controller

package com.example.demo.controller;

import com.example.demo.entity.User;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/user")
public class UserController {

    @Autowired
    private UserService userService;

    @PostMapping("/addUser")
    public User addUser(@RequestBody User user){
        System.out.println(user);
        userService.save(user);

        return user;
    }

    @GetMapping("/getUserById/{id}")
    public User getUserById(@PathVariable Long id){
        User user = userService.getById(id);
        user.setId(14L);
        return user;
    }
}

api测试

POST http://localhost:8080/api/user/addUser
Content-Type: application/json

{
  "name": "Tom",
  "age": 20
}


###

GET http://localhost:8080/api/user/getUserById/1

###

遗留问题：

数据库连接池使用druid，项目启动报错，使用hikari成功启动