hibernate配置oracle生成序列结果为负数

原文链接：http://blog.csdn.net/z634075513/article/details/51554194

工作中使用到了oracle12的版本，使用hibernate5保存时发现生成的结果除了1正常其余的都从-49开始往上加，

数据库自身查询是没有问题的。

跟踪hibernate5的源码发现@SequenceGenerator还需要配置一个allocationSize=1才能正常

如

@SequenceGenerator(name="UMS_USER_SEQ", sequenceName="UMS_USER_SEQ",allocationSize = 1)

相关源码在org.hibernate.id.enhanced.PooledOptimizer#generat

generationState.value = callback.getNextValue();// unfortunately not really safe to normalize this// to 1 as an initial value like we do the others// because we would not be able to control this if// we are using a sequence...if ( generationState.value.lt( 1 ) ) {log.pooledOptimizerReportedInitialValue( generationState.value );}// the call to obtain next-value just gave us the initialValueif ( ( initialValue == -1&& generationState.value.lt( incrementSize ) )|| generationState.value.eq( initialValue ) ) {generationState.hiValue = callback.getNextValue();}else {generationState.hiValue = generationState.value;generationState.value = generationState.hiValue.copy().subtract( incrementSize - 1 );}

问题:

1.有如下sequenceGenerator,用的哪个?

sequenceGenerator: (sequenceHiLoGenerator, sequenceIdentityGenerator)

sequenceStyleGenerator

2.有如下Optimizer, 用的哪个?

PooledOptimizer/PooledLoOptimizer/HiLoOptimizer/LegacyHiLoAlgorithmOptimizer()/NoopOptimizer;