springboot aop实现多数据源 读写分离

实现思路：继承 AbstractRoutingDataSource 实现动态切换（aop对于主从变量进行切换）根据变量key读取对应的数据源实例 必须覆盖SqlSessionFactory 、SqlSessionTemplate 

@Configuration
public class DataSourceConfig {
    /**
     * 主数据库数据源，存入Spring容器
     * 注解@Primary表示主数据源
     * @return
     */
    @ConfigurationProperties(prefix = "spring.datasource.master")
    @Primary
    @Bean
    public DataSource masterDataSource(){
        return DruidDataSourceBuilder.create().build();
    }

    /**
     * 从数据库数据源，存入Spring容器
     * @return
     */
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    @Bean
    public DataSource slaveDataSource(){
        return DruidDataSourceBuilder.create().build();
    }

    /**
     * 决定最终数据源
     * @param masterDataSource
     * @param slaveDataSource
     * @return
     */
    @Bean
    public DynamicDataSource targetDataSource(@Qualifier("masterDataSource") DataSource masterDataSource, @Qualifier("slaveDataSource") DataSource slaveDataSource){
        //存放主从数据源
        Map<Object,Object> targetDataSource = new HashMap<>(2);
        //主数据源
        targetDataSource.put(DBTypeEnum.MASTER, masterDataSource);
        //从数据源
        targetDataSource.put(DBTypeEnum.SLAVE, slaveDataSource);
        //实现动态切换
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        //绑定所有数据源
        dynamicDataSource.setTargetDataSources(targetDataSource);
        //设置默认数据源
        dynamicDataSource.setDefaultTargetDataSource(masterDataSource);
        return dynamicDataSource;
    }

    @Bean
    public SqlSessionFactory sessionFactory(@Qualifier("targetDataSource") DataSource dynamicDataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setMapperLocations(
                new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/*"));
        bean.setDataSource(dynamicDataSource);
        return bean.getObject();
    }

    @Bean
    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("sessionFactory") SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory, ExecutorType.BATCH);
    }

    /***
     * 当自定义数据源，用户必须注入，否则事务控制不生效
     * @param dataSource
     * @return
     */
    @Bean
    public DataSourceTransactionManager dataSourceTx(@Qualifier("targetDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
}

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public class DynamicDataSource extends AbstractRoutingDataSource {

    private Logger logger = LoggerFactory.getLogger(DynamicDataSource.class);

    @Override
    protected Object determineCurrentLookupKey() {
        logger.info("使用数据源："+DynamicDbUtil.get());
        return DynamicDbUtil.get();
    }
}

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@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@Documented
public @interface DBType {

    DBTypeEnum dbType() default DBTypeEnum.MASTER;

}

public enum DBTypeEnum {
    /**
     * 主数据库
     */
    MASTER,

    /**
     * 从数据库
     */
    SLAVE;
}
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@Aspect
@Component
public class DataSourceAopAspect {
    private Logger logger = LoggerFactory.getLogger(DataSourceAopAspect.class);

    @Pointcut("@annotation(com.cn.datasource.annotation.DBType)")
    public void dataSourceAopAspect(){

    }

    /**
     * 配置前置通知，切换数据源为从数据库
     */
    @Before("dataSourceAopAspect()")
    public void readAdvise(JoinPoint joinPoint){
        Signature signature = joinPoint.getSignature();
        MethodSignature methodSignature = (MethodSignature) signature;
        Method method = methodSignature.getMethod();
        DBType dbTypeAn = method.getAnnotation(DBType.class);
        DBTypeEnum dbType = dbTypeAn.dbType();
        //先移除
        DynamicDbUtil.remove();
        //设置数据源
        DynamicDbUtil.set(dbType);
        logger.info("切换到数据源："+DynamicDbUtil.get());
    }
}