多數據源及事物在fast-family-master基礎框架中設計實踐指

多數據源及事物在fast-family-master基礎框架中設計實踐指南

本篇給你們介紹如何設計開發多數據源及多數據源事物。

閱讀本篇文章涵蓋知識點以下：

1.註解反射

2.Spring Aop代理

3.ThreadLocal

4.XA事物管理

具體實現以下：

建立動態數據源切換註解

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


    String name() default "";
}
複製代碼

使用aop代理DataSourceAnnotation註解進行數據源切換

@Aspect
@Component
@Slf4j
@Order(1)
public class DynamicDataSourceAspect {


    @Pointcut("@within(com.fast.family.datasource.annotation.DataSourceAnnotation) ||" +
            " @annotation(com.fast.family.datasource.annotation.DataSourceAnnotation)")
    public void pointcut() {
    }

    ;


    @Before("pointcut()")
    public void before(JoinPoint joinPoint) {
        Method method = ((MethodSignature) joinPoint.getSignature()).getMethod();
        DataSourceAnnotation dataSourceAnnotation =
                method.getAnnotation(DataSourceAnnotation.class);
        if (dataSourceAnnotation == null) {
            dataSourceAnnotation = joinPoint.getTarget().getClass()
                    .getAnnotation(DataSourceAnnotation.class);
            if (dataSourceAnnotation == null) {
                return;
            }
        }
        String dataSourceKey = dataSourceAnnotation.name();
        if (dataSourceKey != null) {
            DataSourceContextHolder.add(dataSourceKey);
        }
    }

    public void after(JoinPoint joinPoint) {
        DataSourceContextHolder.clear();
    }
}
複製代碼

建立動態數據源接口

public interface DynamicDataSource {


    Map<Object, Object> loadDataSource();

}
複製代碼

加載配置文件指定的數據源信息

@Component
@Slf4j
public class DefaultDynamicDataSouce implements DynamicDataSource {

    @Autowired
    private DynamicDataSourceProperties properties;

	//加載配置的數據源信息進緩存
    @Override
    public Map<Object, Object> loadDataSource() {
        Class<? extends DataSource> type = properties.getType();
        DataSource result = (DataSource) BeanUtils.instantiate(type);
        Map<String, DynamicDataSourceProperties> map = properties.getDatasource();
        Iterator<Map.Entry<String, DynamicDataSourceProperties>> iterator = map.entrySet().iterator();

        Map<Object, Object> dataSourceMap = new HashMap<>();
        while (iterator.hasNext()) {
            Map.Entry<String, DynamicDataSourceProperties> entry = iterator.next();
            DataSource dataSource = DynamicDataSourceFatcory.createDateSource(entry.getValue(), result);
            dataSourceMap.put(entry.getKey(), dataSource);
            DynamicDataSourceCacheUtils.put(entry.getKey(), dataSource);
        }
        return dataSourceMap;
    }
}
複製代碼

多數據源Properties配置文件

@Data
@ConfigurationProperties(prefix = "fast.family")
public class DynamicDataSourceProperties {

    private Class<? extends DataSource> type;

    private DruidDataSourceProperties druid;

    private AtomikosDataSouceProperties atomikos = new AtomikosDataSouceProperties();

    private Map<String, DynamicDataSourceProperties> datasource = new HashMap<>();

}
複製代碼

繼承AbstractRoutingDataSource來進行數據源切換

@Slf4j
public class DynamicRoutingDataSource extends AbstractRoutingDataSource
        implements InitializingBean {

    @Autowired
    private DynamicDataSourceProperties properties;

    @Autowired
    private DynamicDataSource dynamicDataSource;

    @Override
    protected DataSource determineTargetDataSource() {
        String dataSourceKey = DataSourceContextHolder.get();
        //根據DataSourceAnnotation指定數據源名稱來切換數據源
        //默認使用master數據源
        if (dataSourceKey != null && !dataSourceKey.equals("")) {
            return DynamicDataSourceCacheUtils.get(dataSourceKey);
        } else {
            return DynamicDataSourceCacheUtils.get("master");
        }
    }


    @Override
    protected Object determineCurrentLookupKey() {
        return DataSourceContextHolder.get();
    }

    @Override
    public void afterPropertiesSet() {
        this.setTargetDataSources(dynamicDataSource.loadDataSource());
    }


}
複製代碼

丟進spring 容器

@Configuration
@ConditionalOnClass(DynamicDataSourceProperties.class)
@EnableConfigurationProperties({DynamicDataSourceProperties.class})
public class DynamicDataSourceAutoConfigure {


    @Bean
    public DynamicRoutingDataSource routingDataSource() {
        return new DynamicRoutingDataSource();
    }
}
複製代碼

疑問：

上述代碼已經實現了基本的數據源切換，那麼你們可能會有一個疑問就是，多數據源及事物，這個事物是在哪裏管理呢？ 這個時候就須要引入XA事物了。

其實奧祕就在DynamicDataSourceProperties中的type屬性，以阿里druid數據源爲例。

fast:
  family:
    type: com.alibaba.druid.pool.xa.DruidXADataSource #指定DruidXADataSource則帶有分佈式XA事物管理，指定DruidDataSource則不具有分佈式XA事物管理
    datasource:
      master:
        druid:
          username: root
          password: root
          url: jdbc:mysql://localhost:3306/master-db?useUnicode=true&characterEncoding=utf8
          driverClassName: com.mysql.jdbc.Driver
        atomikos:
          uniqueResourceName: master-db
      slave_0:
        druid:
          username: root
          password: root
          url: jdbc:mysql://localhost:3306/slave-db?useUnicode=true&characterEncoding=utf8
          driverClassName: com.mysql.jdbc.Driver
        atomikos:
          uniqueResourceName: slave-db
複製代碼

最後各位讀者以爲本篇文章對您有所幫助，能夠點贊一波。

如對fast-family-master基礎框架感興趣能夠star一波，地址以下：

https://github.com/fast-family/fast-family-master