springboot2 + mybatis 多種方式實現多數據配置

時間 2020-03-30

標籤 springboot2 springboot mybatis 多種方式實現數據配置欄目 Spring 简体版

原文原文鏈接

業務系統複雜程度增長，爲了解決數據庫I/O瓶頸，很天然會進行拆庫拆表分服務來應對。這就會出現一個系統中可能會訪問多處數據庫，須要配置多個數據源。java

第一種場景：項目服務從其它多處數據庫取基礎數據進行業務處理，所以各庫之間不會出現重表等狀況。mysql

第二種場景：爲了減輕寫入壓力進行讀寫分庫，讀走從庫，寫爲主庫。此種表名等信息皆爲一致。git

第三種場景：以上兩種皆有。對於某些業務須要大數據量的彙總統計，但願不影響正常業務必須走從庫（表信息一致），某些配置信息不存在讀寫壓力，出現不分庫（表信息不一致）github

項目源代碼：spring

https://github.com/zzsong/springboot-multiple-datasource.git

有三個目錄：sql

one:
    直接使用多@Bean配置，@MapperScan來路徑區分讀何庫
 
two:
 使用註解的方式來標識走何dataSource,AOP攔截注入動態數據源 

third:
 使用spring的Bean命名策略進行區分數據來源

項目技術選型： springBoot2.2.5 + mybatis + druid + mysql數據庫

先看主要的pom包springboot

        <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.5.RELEASE</version>
        <relativePath/> 
    </parent>

                <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.2</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.19</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.21</version>
        </dependency>

application.ymlsession

spring:
  datasource:
    druid:
      core:
        url: jdbc:mysql:///kc_core?characterEncoding=utf-8&serverTimezone=Asia/Shanghai
        username: root
        password: 123456
        driver-class-name: com.mysql.cj.jdbc.Driver
        type: com.alibaba.druid.pool.DruidDataSource
      schedule:
        url: jdbc:mysql:///kc_schedule?characterEncoding=utf-8&serverTimezone=Asia/Shanghai
        username: root
        password: 123456
        driver-class-name: com.mysql.cj.jdbc.Driver
        type: com.alibaba.druid.pool.DruidDataSource

mysql新版本必須帶有serverTimezone，否則會報鏈接異常。mybatis

第一種：經過@MapperScans 掃描匹配相關的數據源

@Configuration
@MapperScans({
        @MapperScan(basePackages = "com.zss.one.mapper.core", sqlSessionTemplateRef = "coreSqlSessionTemplate",sqlSessionFactoryRef = "coreSqlSessionFactory"),
        @MapperScan(basePackages = "com.zss.one.mapper.schedule", sqlSessionTemplateRef = "scheduleSqlSessionTemplate",sqlSessionFactoryRef = "scheduleSqlSessionFactory")
})
public class MybatisOneConfig {

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.druid.core")
    public DataSource coreDataSource(){
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    public SqlSessionFactory coreSqlSessionFactory(@Qualifier("coreDataSource") DataSource coreDataSource) throws Exception {
        SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(coreDataSource);
        sessionFactory.getObject().getConfiguration().setJdbcTypeForNull(null);
        sessionFactory.getObject().getConfiguration().setMapUnderscoreToCamelCase(true);
        return sessionFactory.getObject();
    }

    @Bean
    public SqlSessionTemplate coreSqlSessionTemplate(@Qualifier("coreSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

    //======schedule========
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.druid.schedule")
    public DataSource scheduleDataSource(){
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    public SqlSessionFactory scheduleSqlSessionFactory(@Qualifier("scheduleDataSource") DataSource coreDataSource) throws Exception {
        SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(coreDataSource);
        sessionFactory.getObject().getConfiguration().setJdbcTypeForNull(null);
        sessionFactory.getObject().getConfiguration().setMapUnderscoreToCamelCase(true);
        return sessionFactory.getObject();
    }

    @Bean
    public SqlSessionTemplate scheduleSqlSessionTemplate(@Qualifier("scheduleSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

第二種是動態數據源模式，經過AOP切入註解引導使用何數據源。用自定義註解@interface來標識方法走對應的數據源。

注意事項：類中的方法再調用帶數據源的方法，不能被AOP切入

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {
    String value();
}

extends spring的動態DataSource路由來匹配

public class DynamicDataSource extends AbstractRoutingDataSource {

    @Override
    protected Object determineCurrentLookupKey() {
        return  DataSourceContextRouting.getDataSourceName();
    }
}

@Configuration
//@EnableConfigurationProperties(MybatisProperties.class)//不要使用此公共配置，Configuration會破壞相關dataSource的配置
@MapperScan("com.zss.two.mapper")
public class MybatisConfig {

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.druid.core")
    public DataSource coreDataSource() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.druid.schedule")
    public DataSource scheduleDataSource() {
        return DruidDataSourceBuilder.create().build();
    }



    @Autowired
    @Qualifier("coreDataSource")
    private DataSource coreDataSource;

    @Autowired
    @Qualifier("scheduleDataSource")
    private DataSource scheduleDataSource;

    @Bean
    public DynamicDataSource dataSource() {
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DataSourceConstants.CORE_DATA_SOURCE, coreDataSource);
        targetDataSources.put(DataSourceConstants.SCHEDULE_DATA_SOURCE, scheduleDataSource);

        DynamicDataSource dataSource = new DynamicDataSource();

        //設置數據源映射
        dataSource.setTargetDataSources(targetDataSources);
////        設置默認數據源，當沒法映射到數據源時會使用默認數據源
        dataSource.setDefaultTargetDataSource(coreDataSource);
        dataSource.afterPropertiesSet();
        return dataSource;
    }
    /**
     * 根據數據源建立SqlSessionFactory
     */
    @Bean
    public SqlSessionFactory sqlSessionFactory(DynamicDataSource dataSource) throws Exception {
        SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(dataSource);
        sessionFactory.getObject().getConfiguration().setJdbcTypeForNull(null);
        sessionFactory.getObject().getConfiguration().setMapUnderscoreToCamelCase(true);
        return sessionFactory.getObject();
    }

    @Bean
    public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

第三種，自定義Bean命名策略，按beanName進行自動匹配使用數據源

@Component
public class CoreBeanNameGenerator implements BeanNameGenerator {
    @Override
    public String generateBeanName(BeanDefinition definition, BeanDefinitionRegistry registry) {
        return "core"+ ClassUtils.getShortName(definition.getBeanClassName());
    }
}


@Component
public class ScheduleBeanNameGenerator implements BeanNameGenerator {
    @Override
    public String generateBeanName(BeanDefinition definition, BeanDefinitionRegistry registry) {
        return "schedule"+ ClassUtils.getShortName(definition.getBeanClassName());
    }
}

使用mybatis MapperScannerConfigurer自動掃描，將Mapper接口生成注入到spring

    @Bean
    public MapperScannerConfigurer coreMapperScannerConfig(CoreBeanNameGenerator coreBeanNameGenerator){
        MapperScannerConfigurer configurer = new MapperScannerConfigurer();
        configurer.setNameGenerator(coreBeanNameGenerator);
        configurer.setBasePackage("com.zss.third.mapper.core,com.zss.third.mapper.order");
        configurer.setSqlSessionFactoryBeanName("coreSqlSessionFactory");
        configurer.setSqlSessionTemplateBeanName("coreSqlSessionTemplate");
        return configurer;
    }



    @Bean
    public MapperScannerConfigurer scheduleMapperScannerConfig(ScheduleBeanNameGenerator scheduleBeanNameGenerator){
        MapperScannerConfigurer configurer = new MapperScannerConfigurer();
        configurer.setNameGenerator(scheduleBeanNameGenerator);
        configurer.setBasePackage("com.zss.third.mapper.schedule,com.zss.third.mapper.order");
        configurer.setSqlSessionFactoryBeanName("scheduleSqlSessionFactory");
        configurer.setSqlSessionTemplateBeanName("scheduleSqlSessionTemplate");
        return configurer;
    }