Foreword:
In the process of doing a project, you may need to use multiple databases. Using @DS to switch data sources, you must first figure out the correct way to use the @DS annotation
Open method:
When the annotation is added to the class, it means that the methods in this class use this data source;
when the annotation is added to the method, it means that the data source used on this method has priority over all other configurations;
Error example:
@Service
public class ServiceImpl implements Service{
/**
* 实现方法A
* @param
* @return
*/
@Override
@DS("database1")
@Transactional(propagation = Propagation.REQUIRES_NEW, rollbackFor = Exception.class)
public void functionA() {
...
functionB(); //调用B方法且切换为B方法的所需要的数据源
}
/**
* 实现方法B
* @param
* @return
*/
@Override
@DS("database2")
@Transactional(propagation = Propagation.REQUIRES_NEW, rollbackFor = Exception.class)
public void function B() {
}
}Error: When method A calls method B, the @DS annotation of method B will not take effect and will be completely covered by @DS ("database1) of method A.
Analysis of the cause of the error : The above method is only applicable to the use of different methods and different data sources in the same class, and transactions cannot be used , otherwise the data source will not switch.
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The correct way to open : call methods in different classes
In particular, it is important to remember to open the transaction
@Service("serviceA")
public class ServiceImplA implements ServiceA{
@Resource
ServiceImplB serviceImplB ;
/**
* 实现方法A
* @param
* @return
*/
@Override
@Transactional(propagation = Propagation.REQUIRES_NEW, rollbackFor = Exception.class)
@DS("database1")
public void functionA() {
...
ServiceImplB.functionB(); //调用B类的B方法
}
}
@Service("serviceB")
public class ServiceImplB implements ServiceB{
/**
* 实现方法B
* @param
* @return
*/
@Override
@DS("database2")
@Transactional(propagation = Propagation.REQUIRES_NEW, rollbackFor = Exception.class)
public void function B() {
}
}