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SpringBoot+Mybatis-Plus整合Sharding-JDBC5.1.1实现单库分表

掉发的小王

发布于 2022-07-11 08:16:35

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文章被收录于专栏：小王知识分享小王知识分享

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代码可运行

一、前言

小编最近一直在研究关于分库分表的东西，前几天docker安装了mycat实现了分库分表，但是都在说mycat的bug很多。很多人还是倾向于shardingsphere，其实他是一个全家桶，有JDBC、Proxy 和 Sidecar组成，小编今天以最简单的JDBC来简单整合一下！现在最新版已经是5.1.1，经过一天的研究用于解决了所有问题，完成了单库分表！！

想了解4.0.0版本的可以看一下小编刚刚写的：SpringBoot+Mybatis-Plus整合Sharding-JDBC4.0.0实现单库分表如果想看mycat的可以看一下小编之前写的文章哈：Docker安装Mycat和Mysql进行水平分库分表实战

二、踩过的坑

1. 数据源问题

不要使用druid-spring-boot-starter这个依赖，启动会有问题

<dependency>-->
	<groupId>com.alibaba</groupId>
	<artifactId>druid-spring-boot-starter</artifactId>
	<version>1.1.21</version>
/dependency>

报错信息：

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userMapper' defined in file 
[D:\jiawayun\demo\target\classes\com\example\demo\mapper\UserMapper.class]:
 Invocation of init method failed; nested exception is 
 java.lang.IllegalArgumentException: Property 'sqlSessionFactory' 
 or 'sqlSessionTemplate' are required

==解决方案：==

使用单独的druid

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.2.8</version>
</dependency>

建议使用==默认的数据源==，sharding-jdbc也是使用的默认的数据源，小编使用的自带的，忘记druid后面会不会有问题了！！

type: com.zaxxer.hikari.HikariDataSource

2. Insert 语句不支持分表路由到多个数据节点

报错信息： Insert statement does not support sharding table routing to multiple data nodes.

解决方案：看小编文章：解决不支持分表路由问题

三、导入maven依赖

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

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
    <exclusions>
        <exclusion>
            <groupId>org.junit.vintage</groupId>
            <artifactId>junit-vintage-engine</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>shardingsphere-jdbc-core-spring-boot-starter</artifactId>
    <version>5.1.1</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>
<!-- lombok -->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.10</version>
</dependency>
<!--jdbc-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<!-- mysql -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

<!-- mybatis-plus -->
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.5.1</version>
</dependency>

四、新建表

1. 新建二张表

命名为：user_0、user_1

CREATE TABLE `user_0`  (
  `cid` bigint(25) NOT NULL,
  `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `gender` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `data` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  PRIMARY KEY (`cid`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

SET FOREIGN_KEY_CHECKS = 1;

2. 数据库结构

五、框架全局展示

1. User实体类

@Data
public class User implements Serializable {
    private static final long serialVersionUID = 337361630075002456L;
    
    private Long cid;
    
    private String name;

    private String gender;

    private String data;

}

2. controller

@RestController
@RequestMapping("/test")
public class UserController {

    @Autowired
    private UserMapper userMapper;

    @GetMapping("/insertTest")
    public void insertTest(){
        for (int i = 1 ; i < 10; i++) {
            User test = new User("王"+i,"男","数据" + i);
            userMapper.insert(test);
        }
    }
}

3. mapper

我们直接省略了service，简单一下哈！！

public interface UserMapper extends BaseMapper<User> {
}

4. application.yml配置

server:
  port: 8089

spring:
  shardingsphere:
    mode:
      type: memory
    # 是否开启
    datasource:
      # 数据源（逻辑名字）
      names: m1
      # 配置数据源
      m1:
        type: com.zaxxer.hikari.HikariDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://localhost:3306/test?useSSL=false&autoReconnect=true&characterEncoding=UTF-8&serverTimezone=UTC
        username: root
        password: root
    # 分片的配置
    rules:
      sharding:
        # 表的分片策略
        tables:
          # 逻辑表的名称
          user:
            # 数据节点配置，采用Groovy表达式
            actual-data-nodes: m1.user_$->{0..1}
            # 配置策略
            table-strategy:
              # 用于单分片键的标准分片场景
              standard:
                sharding-column: cid
                # 分片算法名字
                sharding-algorithm-name: user_inline
            key-generate-strategy: # 主键生成策略
              column: cid  # 主键列
              key-generator-name: snowflake  # 策略算法名称(推荐使用雪花算法)
        key-generators:
          snowflake:
            type: SNOWFLAKE
        sharding-algorithms:
          user_inline:
            type: inline
            props:
              algorithm-expression: user_$->{cid % 2}
    props:
      # 日志显示具体的SQL
      sql-show: true


logging:
  level:
    com.wang.test.demo: DEBUG

mybatis-plus:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.example.demo.entity
  configuration:
    #在映射实体或者属性时，将数据库中表名和字段名中的下划线去掉，按照驼峰命名法映射 address_book ---> addressBook
    map-underscore-to-camel-case: true

5. 启动类

@MapperScan("com.example.demo.mapper")
@SpringBootApplication
public class DemoApplication {

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

}

六、测试插入九条数据

==本次测试策略是：行表达式分片策略:inline==

1. 插入数据

输入：localhost:8089/test/insertTest

==分片成功==

2. 单个查询

@GetMapping("/selectOneTest")
public void selectOneTest(){

    User user = userMapper.selectOne(Wrappers.<User>lambdaQuery().eq(User::getCid,736989417020850176L));
    System.out.println(user);

}

这时他会根据cid去自动获取去那个表中获取数据

3. 全查询

@GetMapping("/selectListTest")
public void selectListTest(){

    List<User> list = userMapper.selectList(null);
    System.out.println(list);

}

由于没有条件，他会去把两个表UNION ALL进行汇总

4. 分页查询

需要先配置mybatis-plus分页配置类：

@Configuration
public class MybatisPlusConfig {

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }
}

@GetMapping("/selectListPage")
public void selectListPage(){
    IPage<User> page = new Page(1,6);
    IPage<User> userIPage = userMapper.selectPage(page,null);
    List<User> records = userIPage.getRecords();
    System.out.println(records);
}

我们user_0有5条数据，user_1有4条数据

==我们发现它会向所有的表中去进行一遍分页查询，第一个表数据不够就会加上另一个表分页拿到的值==

==分页size为3时，一个user_0就可以满足分页条件，就会忽略user_1的分页数据。==

5. 非分片属性查询

我们先把user_0表性别修改两个为女，然后进行查询！看看没有分片的字段是否能够只去user_0去查询

@GetMapping("/selectListByGender")
public void selectListByGender(){

    List<User> list = userMapper.selectList(Wrappers.<User>lambdaQuery().eq(User::getGender, "女"));
    System.out.println(list);
}

有图可见：不是分片的字段查询，回去全连接表去查询一遍，效率和不分表一样了哈！！

6. 分片属性来自一个表in查询

@GetMapping("/selectInList")
public void selectList(){
    List<User> users = userMapper.selectList(Wrappers.<User>lambdaQuery().in(User::getCid,736989417020850176L,736989418119757824L));
    System.out.println(users);
}