Java 如何使用 Hibernate 获取最后插入的 ID
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How can I get last inserted id using Hibernate
提问by Mohit Bhansali
I want to fetch the last inserted value's id in Hibernate.
我想在 Hibernate 中获取最后插入的值的 id。
After search:
搜索后：
Long lastId = ((Long) session.createSQLQuery("SELECT LAST_INSERT_ID()").uniqueResult()).longValue();
But the following code gives me this error:
但是下面的代码给了我这个错误：
java.lang.ClassCastException: java.math.BigInteger cannot be cast to java.lang.Long
java.lang.ClassCastException: java.math.BigInteger 不能转换为 java.lang.Long
Please share your thoughts!
请分享您的想法！
Solution
解决方案
Long lastId = ((BigInteger) session.createSQLQuery("SELECT LAST_INSERT_ID()").uniqueResult()).longValue();
Don't forget to import:
不要忘记导入：
import java.math.BigInteger;
导入 java.math.BigInteger;
采纳答案by Suresh Atta
Error is pretty clear. It's returning BigIntegerand not long
错误很明显。它正在返回BigInteger而不是long
You have to assign it to a BigInteger. And get longValue()from it.
您必须将其分配给BigInteger. 并从中获得longValue()。
回答by bobbel
Since the return type of uniqueResult()is BigIntegerand not Long, you should do it like this:
由于uniqueResult()isBigInteger和 not的返回类型Long，您应该这样做：
long lastId = session.createSQLQuery("SELECT LAST_INSERT_ID()")
.uniqueResult() // this returns a BigInteger
.longValue(); // this will convert it to a long value
The method uniqueResult()only returns a BigInteger because of your query SELECT LAST_INSERT_ID().
uniqueResult()由于您的查询，该方法仅返回一个 BigInteger SELECT LAST_INSERT_ID()。
回答by surya handoko
public Integer save(Smartphones i) {
int id = 0;
Session session=HibernateUtil.getSessionFactory().openSession();
Transaction trans=session.beginTransaction();
try{
session.save(i);
id=i.getId();
trans.commit();
}
catch(HibernateException he){}
return id;
}
回答by Linyun Liu
You can simply use save which returns a Serializable object that actually is the last insert id. Sample code:
您可以简单地使用 save 返回一个 Serializable 对象，该对象实际上是最后一个插入 id。示例代码：
Session session=this.getSessionFactory().getCurrentSession();
int result = -1;
try {
Serializable ser = session.save(paper);
if (ser != null) {
result = (Integer) ser;
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
A testing run:
测试运行：
int result = paperService.save(paper);
System.out.println("The id of the paper you just added is: "+result);
and here is the output:
这是输出：
The id of the paper you just added is: 3032
