利用MybatisPlus两步实现多租户方案

1.定义一个TenantLineHandler的实现类：

import com.baomidou.mybatisplus.extension.plugins.handler.TenantLineHandler;
import com.google.common.collect.Lists;
import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.expression.LongValue;

import java.util.List;

/**
 * 多租户处理插件
 *
 * @author 向振华
 * @date 2021/04/26 13:37
 */
public class CustomTenantLineHandler implements TenantLineHandler {

    /**
     * 忽略添加租户ID的表
     */
    private final static List IGNORE_TABLE_NAMES = Lists.newArrayList(
            "t_country",
            "t_language"
    );

    /**
     * 获取租户ID值表达式(可从cookie、token、缓存中取)
     *
     * @return
     */
    @Override
    public Expression getTenantId() {
        return new LongValue(1L);
    }

    /**
     * 获取租户字段名(数据库的租户ID字段名)
     *
     * @return
     */
    @Override
    public String getTenantIdColumn() {
        return "tenant_id";
    }

    /**
     * 根据表名判断是否忽略拼接多租户条件
     *
     * @param tableName
     * @return
     */
    @Override
    public boolean ignoreTable(String tableName) {
        return IGNORE_TABLE_NAMES.contains(tableName);
    }
}

2.定义MybatisPlusConfig配置类将多租户插件生效：

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.autoconfigure.ConfigurationCustomizer;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.TenantLineInnerInterceptor;
import com.bzcst.bop.component.mybatis.config.handler.AutoFillMetaObjectHandler;
import com.bzcst.bop.component.mybatis.config.handler.CustomTenantLineHandler;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @author 向振华
 * @date 2021/04/26 14:45
 */
@Configuration
@MapperScan("scan.your.mapper.package")
public class MybatisPlusConfig {

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        // 多租户插件（注意：这个一定要放在最上面）
        interceptor.addInnerInterceptor(new TenantLineInnerInterceptor(new CustomTenantLineHandler()));
        // 分页插件
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }

    @Bean
    public ConfigurationCustomizer configurationCustomizer() {
        return configuration -> configuration.setUseDeprecatedExecutor(false);
    }

    @Bean
    public AutoFillMetaObjectHandler fillMetaObjectHandler() {
        return new AutoFillMetaObjectHandler();
    }
}

测试

    @Test
    public void select() {
        Role role = roleService.getById(40L);
        System.out.println(role);
    }

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2fedfff1] was not registered for synchronization because synchronization is not active
Original SQL: SELECT id,tenant_id,frame_id,name,type,description,meta_created,meta_updated,meta_logic_flag FROM t_sec_role WHERE id=? 
parser sql: SELECT id, tenant_id, frame_id, name, type, description, meta_created, meta_updated, meta_logic_flag FROM t_sec_role WHERE id = ? AND tenant_id = 1
2021-04-26 14:58:55.534  INFO 24980 --- [           main] com.zaxxer.hikari.HikariDataSource       : DatebookHikariCP - Starting...
2021-04-26 14:58:55.903  INFO 24980 --- [           main] com.zaxxer.hikari.HikariDataSource       : DatebookHikariCP - Start completed.
JDBC Connection [HikariProxyConnection@1100660981 wrapping com.mysql.cj.jdbc.ConnectionImpl@628fa8ea] will not be managed by Spring
==>  Preparing: SELECT id, tenant_id, frame_id, name, type, description, meta_created, meta_updated, meta_logic_flag FROM t_sec_role WHERE id = ? AND tenant_id = 1
==> Parameters: 40(Long)
<==    Columns: id, tenant_id, frame_id, name, type, description, meta_created, meta_updated, meta_logic_flag
<==        Row: 40, 1, 123, 一个角色啊, 2, haha, 2021-04-26 14:07:42, 2021-04-26 14:07:42, 1
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2fedfff1]
Role(id=40, sasTenantId=1, orgFrameId=123, name=一个角色啊, type=2, description=haha, metaCreated=Mon Apr 26 14:07:42 CST 2021, metaUpdated=Mon Apr 26 14:07:42 CST 2021, metaLogicFlag=1)

可以看到查询语句后面拼接了tenant_id = 1

==>  Preparing: SELECT id, tenant_id, frame_id, name, type, description, meta_created, meta_updated, meta_logic_flag FROM t_sec_role WHERE id = ? AND tenant_id = 1

注意：如果表中没有定义tenant_id会报错，不需要添加多租户的表配置到CustomTenantLineHandler 中的IGNORE_TABLE_NAMES集合中