Question

I m using Session.save() method (in Hibernate) to persist my entity objects which returns an object of type java.io.Serializable.

The returned value is the generated primary key for the entity.

The generated primary key is of type long (or bigint).

问题是:我如何将返还价值转换成long?

Serializable result = session.save(myEntityObject);

//This line of code fails. 
long r = (long)result;

Answer 1

Try casting the result (since it s not a primitive) to Long instead of long.

Long r = (Long)result;
long longValue = r.longValue();

Answer 2

Try

long r = Long.valueOf(String.valueOf(result)).longValue();

Answer 3

Have you tried using a debugger and breaking at that line to see what "result" is exactly?

它可以是大Dec或长 or,或......

或者说,你只是把主要的关键采集方法称作目标,我希望到那个时候确定。

HTH, Chris

Answer 4

Try using long r = ((Long) result).getLong() instead.

Answer 5

您本应指明你正在经历的错误类型! 任何途径都应奏效。

long r = Long.valueOf(result)

Answer 6

Above answer not worked for me.

I misunderstood the function of statelessSession.get(...). The second parameter should be the primitive value of the primary-key if it is a non-composte key.

如果实体拥有一个综合钥匙,你应将实体本身(填满了克)作为第二点。

I was confused, because I thought that I need to pass always an entity as second argument to statelessSession.get (because it works for multi-key-entitys).

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