java Springdatajpa什么时候开始。save（）是否返回相同的实体？

Question

在这段代码中，我保存了主对象和该对象的外键。 我打印出“实体”和“事物”，它们应该是完全相同的对象。但他们不是。为什么

thingList.forEach(entity -> {
            System.out.println(entity);

            // Save if the foreign key exists and isn't already saved in the database
            if(entity.ForeignKey() != null && ForeignKeyRepository.findOne(entity.ForeignKey().getId()) == null)
            {
                ForeignKeyRepository.save(entity.getForeignKey());
            }
            Thing thing = thingRepository.save(entity);
            System.out.println(thing);
        });

Answer 1

这就是他们在save方法的文档中提到的例外情况

S save(S entity) : Saves a given entity. Use the returned instance for further operations as the save operation might have changed the entity instance completely.