项目需要配置读写分离，分库分表，选了shardingJDBC，但是shardingJDBC又许多不支持的sql，综合了一下，选择mybaitis-plus做读写分离，遇到分库分表的时候切换sharding数据源，也就是一般情况下使用的还是jdbc，有分表的时候才会用shardingJDBC

    <dependencies>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.24</version>
        </dependency>
        <dependency>
            <groupId>org.apache.shardingsphere</groupId>
            <artifactId>sharding-jdbc-spring-boot-starter</artifactId>
            <version>4.1.1</version>
        </dependency>
                <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.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-aop</artifactId>
                    <version>2.4.2</version>
                </dependency>

                <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <scope>runtime</scope>
                </dependency>
                <dependency>
                    <groupId>org.mybatis.spring.boot</groupId>
                    <artifactId>mybatis-spring-boot-starter</artifactId>
                    <version>2.1.3</version>
                </dependency>

                <!-- mybatis plus start -->
                <dependency>
                    <groupId>com.baomidou</groupId>
                    <artifactId>mybatis-plus</artifactId>
                    <version>3.3.2</version>
                </dependency>
                <dependency>
                    <groupId>com.baomidou</groupId>
                    <artifactId>mybatis-plus-boot-starter</artifactId>
                    <version>3.3.2</version>
                </dependency>
                <!-- mybatis plus end -->

                <dependency>
                    <groupId>com.baomidou</groupId>
                    <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
                    <version>3.2.0</version>
                </dependency>

                <dependency>
                    <groupId>org.apache.commons</groupId>
                    <artifactId>commons-lang3</artifactId>
                    <version>3.9</version>
                </dependency>

                <dependency>
                    <groupId>org.projectlombok</groupId>
                    <artifactId>lombok</artifactId>
                    <optional>true</optional>
                </dependency>
                <dependency>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-jdbc</artifactId>
                </dependency>
    </dependencies>

dynamic-datasource-spring-boot-starter采用3.3以上的好像就切不过来数据源，具体没找到原因

spring:
  datasource:
    dynamic:
      primary: master
      datasource:
        master:
          url: jdbc:mysql://localhost:3306/test_0?characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowMultiQueries=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=Asia/Shanghai
          username: root
          password: root
          driver-class-name: com.mysql.cj.jdbc.Driver
          type: com.alibaba.druid.pool.DruidDataSource
        slave:
          url: jdbc:mysql://localhost:3306/test_s_0?characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowMultiQueries=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=Asia/Shanghai
          username: root
          password: root
          driver-class-name: com.mysql.cj.jdbc.Driver
          type: com.alibaba.druid.pool.DruidDataSource
  shardingsphere:
    datasource:
      names: salve-sharding,slave0
      salve_sharding:
        type: com.alibaba.druid.pool.DruidDataSource
        driverClassName: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://localhost:3306/test_1?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8&useTimezone=true
        username: root
        password: root
      slave0:
        type: com.alibaba.druid.pool.DruidDataSource
        driverClassName: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://localhost:3306/test_s_1?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8&useTimezone=true
        username: root
        password: root
    props:
      sql.show: true
    masterslave:
      load-balance-algorithm-type: round_robin
      master-data-source-name: ms
    sharding:
      master-slave-rules:
        salve-sharding:
          masterDataSourceName: salve-sharding
          slaveDataSourceNames:
            - slave0
      tables:
        tab_survey:
          table-strategy:
            standard:
              sharding-column: customer_id
              preciseAlgorithmClassName: com.ls.demoread.config.MyPreciseShardingAlgorithm
              rangeAlgorithmClassName: com.ls.demoread.config.MyPreciseShardingAlgorithm
          actual-data-nodes: salve-sharding.tab_user_$->{0..1}

#          table-strategy:
#            inline:
#              sharding-column: customer_id
#              algorithm-expression: tab_survey_$->{customer_id % 2}
#          actual-data-nodes: salve-sharding.tab_user_$->{0..1}

logging:
  level:
    com.baomidou.dynamic: debug

配置mybatis-plus读写分离

@Configuration
public class DynamicDatasourceConfig {

    @Bean
    public MasterSlaveAutoRoutingPlugin masterSlaveAutoRoutingPlugin() {
        return new MasterSlaveAutoRoutingPlugin();
    }
}

数据源配置

@Configuration
@AutoConfigureBefore({DynamicDataSourceAutoConfiguration.class,
        SpringBootConfiguration.class})
public class DataSourceConfiguration {

    /**
     * 分表数据源名称
     */
    private static final String SHARDING_DATA_SOURCE_NAME = "salve-sharding";
    /**
     * 动态数据源配置项
     */
    @Autowired
    private DynamicDataSourceProperties properties;

    /**
     * shardingjdbc有四种数据源，需要根据业务注入不同的数据源
     *
     * <p>1. 未使用分片, 脱敏的名称(默认): shardingDataSource;
     * <p>2. 主从数据源: masterSlaveDataSource;
     * <p>3. 脱敏数据源：encryptDataSource;
     * <p>4. 影子数据源：shadowDataSource
     *
     */
    @Lazy
    @Resource(name = "shardingDataSource")
    AbstractDataSourceAdapter shardingDataSource;

    @Bean
    public DynamicDataSourceProvider dynamicDataSourceProvider() {
        Map<String, DataSourceProperty> datasourceMap = properties.getDatasource();
        return new AbstractDataSourceProvider() {
            @Override
            public Map<String, DataSource> loadDataSources() {
                Map<String, DataSource> dataSourceMap = createDataSourceMap(datasourceMap);
                // 将 shardingjdbc 管理的数据源也交给动态数据源管理
                dataSourceMap.put(SHARDING_DATA_SOURCE_NAME, shardingDataSource);
                return dataSourceMap;
            }
        };
    }

    /**
     * 将动态数据源设置为首选的
     * 当spring存在多个数据源时, 自动注入的是首选的对象
     * 设置为主要的数据源之后，就可以支持shardingjdbc原生的配置方式了
     *
     * @return
     */
    @Primary
    @Bean
    public DataSource dataSource(DynamicDataSourceProvider dynamicDataSourceProvider) {
        DynamicRoutingDataSource dataSource = new DynamicRoutingDataSource();
        dataSource.setPrimary(properties.getPrimary());
        dataSource.setStrict(properties.getStrict());
        dataSource.setStrategy(properties.getStrategy());
        dataSource.setProvider(dynamicDataSourceProvider);
        dataSource.setP6spy(properties.getP6spy());
        dataSource.setSeata(properties.getSeata());
        return dataSource;
    }
}

自定义分片

@Slf4j
@Component
public class MyPreciseShardingAlgorithm implements PreciseShardingAlgorithm, RangeShardingAlgorithm {


    @Override
    public String doSharding(Collection collection, PreciseShardingValue preciseShardingValue) {

        //collection:[user_0, user_1]
        // preciseShardingValue:PreciseShardingValue(logicTableName=user, columnName=age, value=20)
        log.info("collection:{}",collection);
        log.info("preciseShardingValue:{}",preciseShardingValue);

        int customId = (int) preciseShardingValue.getValue();
        String tableReal;
        if (String.valueOf(customId).equals("1") || String.valueOf(customId).equals("10") ||String.valueOf(customId).equals("70")){
            tableReal = preciseShardingValue.getLogicTableName().concat("_").concat("0");
        }else {
            tableReal = preciseShardingValue.getLogicTableName().concat("_").concat("1");
        }
        return tableReal;
    }

    @Override
    public Collection<String> doSharding(Collection collection, RangeShardingValue rangeShardingValue) {
        return null;
    }
}

数据源切换
方法或者类上加上注解 @DS("salve-sharding")

配置主从的时候，有时候插入数据，马上查询，可能主从还没同步，这时候可以加上事务的注解，这样子就都会走主库了