Shardingsphere的分库分表+读写分离+分页条件查询
Shardingsphere的分库分表与读写分离
导入依赖
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
<exclusions>
<exclusion>
<groupId>org.junit.vintagegroupId>
<artifactId>junit-vintage-engineartifactId>
exclusion>
exclusions>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>8.0.28version>
dependency>
<dependency>
<groupId>com.baomidougroupId>
<artifactId>mybatis-plus-boot-starterartifactId>
<version>3.5.1version>
dependency>
<dependency>
<groupId>com.baomidougroupId>
<artifactId>mybatis-plus-generatorartifactId>
<version>3.5.2version>
dependency>
<dependency>
<groupId>org.freemarkergroupId>
<artifactId>freemarkerartifactId>
<version>2.3.31version>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>druidartifactId>
<version>1.2.10version>
dependency>
<dependency>
<groupId>org.apache.shardingspheregroupId>
<artifactId>shardingsphere-jdbc-core-spring-boot-starterartifactId>
<version>5.1.1version>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
dependency>
创建数据库，前提是两个服务器做好了主从复制
spring:
shardingsphere:
mode:
type: Memory # 内存模式，元数据保存在当前进程中
datasource:
names: master$->{0..1},slave$->{0..1}
master0: # 跟上面的数据源对应
type: com.alibaba.druid.pool.DruidDataSource # 连接池
url: jdbc:mysql://xxxxxx/test0 # 连接url
username: root
password: 123456
master1: # 跟上面的数据源对应
type: com.alibaba.druid.pool.DruidDataSource
url: jdbc:mysql://xxxxxx/test1
username: root
password: 123456
slave0: # 跟上面的数据源对应
type: com.alibaba.druid.pool.DruidDataSource
url: jdbc:mysql://xxxxxx/test0
username: root
password: 123456
slave1: # 跟上面的数据源对应
type: com.alibaba.druid.pool.DruidDataSource
url: jdbc:mysql://xxxxxx/test1
username: root
password: 123456
rules: # 配置分库分表以及读写分离的规则
sharding: # 配置分库分表规则
tables:
user: # 这个可以随便取，问题不大
actual-data-nodes: master$->{0..1}.user$->{0..2} # 实际节点名称，格式为 库名$->{0..n1}.表名$->{0..n2}
# 其中n1、n2分别为库数量-1和表数量-1
# 也可以使用${0..n1}的形式，但是会与Spring属性文件占位符冲突
# 所以使用$->{0..n1}的形式
database-strategy: # 分库策略
standard: # 标准分库策略
sharding-column: age # 分库列名
sharding-algorithm-name: age-mod # 分库算法名字
table-strategy: # 分表策略
standard: # 标准分表策略
sharding-column: id # 分表列名
sharding-algorithm-name: id-mod # 分表算法名字
sharding-algorithms: # 配置分库和分表的算法
age-mod: # 分库算法名字
type: MOD # 算法类型为取模
props: # 算法配置的键名，所有算法配置都需要在props下
sharding-count: 2 # 分片数量
id-mod: # 分表算法名字
type: MOD # 算法类型为取模
props: # 算法配置的键名，所有算法配置都需要在props下
sharding-count: 3 # 分片数量
readwrite-splitting: # 配置读写分离规则
data-sources: # 数据源
master0: # 这个可以随便取，带有区分意义即可，比如这里表示的是主库test0的规则
type: Static # 静态类型
load-balancer-name: round_robin # 负载均衡算法名字
props: # 具体读写数据源需要配置在props下
write-data-source-name: master0 # 写数据源
read-data-source-names: slave0 # 读数据源
master1:
type: Static # 静态类型
load-balancer-name: round_robin # 负载均衡算法名字
props: # 具体读写数据源需要配置在props下
write-data-source-name: master1 # 写数据源
read-data-source-names: slave1 # 读数据源
load-balancers: # 负载均衡配置
round_robin: # 跟上面负载均衡算法的名字对应
type: ROUND_ROBIN # 负载均衡算法
props:
sql-show: true # 打印SQL
测试
package com.ycz.controller;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;
import com.ycz.entity.User;
import com.ycz.service.IUserService;
import lombok.RequiredArgsConstructor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
import java.util.Random;
@RestController
@RequestMapping("/user")
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
public class UserController {
private final IUserService userService;
@GetMapping("/insert")
public boolean insert() {
User user = new User();
user.setName("啊实打实的撒");
user.setAge(new Random().nextInt(100)+1);
System.out.println(user);
return userService.save(user);
}
@GetMapping("/select")
public List<User> select() {
return userService.list();
}
@GetMapping("/select/{id}")
public Object getById(@PathVariable String id){
return userService.getById(id);
}
@GetMapping("/update/{id}")
public Object update(@PathVariable String id){
UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();
updateWrapper.lambda().set(User::getName , "大萨达十大");
updateWrapper.eq("id" , id);
return userService.update(updateWrapper);
}
}
插入
可以发现写的是主库 master
3311
3312
查询
可以发现读的是从库
分页条件查询
yml
mybatis-plus:
configuration:
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
mapper-locations: classpath*:com/ycz/**/xml/*Mapper.xml
配置config
package com.ycz.config;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
* @Description:
* @Author: Alex
* @Date 2022-06-29-21:58
* @Version: V1.0
**/
@Configuration
public class MybatisPlusConfig {
@Bean
public PaginationInterceptor paginationInterceptor() {
return new PaginationInterceptor();
}
}
@GetMapping("/select")
public Object select(@RequestParam(value = "pageNo" ,required = false , defaultValue = "0")Integer pageNo ,
@RequestParam(value ="pageSize" ,required = false , defaultValue = "5")Integer pageSize) {
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.orderByDesc("age");
Page<User> page = new Page<>(pageNo , pageSize);
IPage<User> pageList = userService.page(page ,queryWrapper);
return pageList;
}
查询结果：
{
"records": [
{
"id": "1540666225414160385",
"name": "test1_user0_2",
"age": 89
},
{
"id": "1540665503343718401",
"name": "test1_user0_1",
"age": 85
},
{
"id": "1540666229851734017",
"name": "test1_user2_2",
"age": 81
},
{
"id": "1540665515347816450",
"name": "test0_user1_1",
"age": 78
},
{
"id": "1540669670086983682",
"name": "test0_user1_3",
"age": 78
}
],
"total": 15,
"size": 5,
"current": 1,
"orders": [],
"optimizeCountSql": true,
"hitCount": false,
"countId": null,
"maxLimit": null,
"searchCount": true,
"pages": 3
}
我们看看其sql语句
sql语句是这样的
slave0 ::: SELECT id,name,age FROM user0 ORDER BY age DESC LIMIT ? ::: [5]
slave0 ::: SELECT id,name,age FROM user1 ORDER BY age DESC LIMIT ? ::: [5]
slave0 ::: SELECT id,name,age FROM user2 ORDER BY age DESC LIMIT ? ::: [5]
slave1 ::: SELECT id,name,age FROM user0 ORDER BY age DESC LIMIT ? ::: [5]
slave1 ::: SELECT id,name,age FROM user1 ORDER BY age DESC LIMIT ? ::: [5]
slave1 ::: SELECT id,name,age FROM user2 ORDER BY age DESC LIMIT ? ::: [5]
sharding JDBC 默认使用limit进行分页，在不指定路由字段时，分页将会全库全表全数据捞取，然后进行排序。