按照ID查找单据

// 动态取对象
                ObjectUuidPK objpk = new ObjectUuidPK(billID);
                IDynamicObject iDynamicObject = DynamicObjectFactory.getLocalInstance(ctx);
                CoreBillBaseInfo billInfo = (CoreBillBaseInfo) iDynamicObject.getValue(objpk
                                .getObjectType(), objpk);

EAS中主键生成有一定规则,可以直接按照主键,不用知道单据类型,查询出对应的单据类型.