Java Persistence：转换为Query.getResultList（）的结果的东西？ [英] Java Persistence: Cast to something the result of Query.getResultList()?

问题描述

嘿，大家，我是新的持久性/休眠，我需要你的帮助。

Hey everyone, I'm new to persistence / hibernate and I need your help.

这里的情况。我有一个表，其中包含一些东西。让我们称他们为人。
我想从数据库中获取该表中的所有条目。

Here's the situation. I have a table that contains some stuff. Let's call them Persons. I'd like to get all the entries from the database that are in that table.

我有一个Person类，它是一个简单的POJO，

I have a Person class that is a simple POJO with a property for each column in the table (name, age,..)

这里是我有的：

Query lQuery = myEntityManager.createQuery("from Person")
List<Person> personList = lQuery.getResultList();

$ 到列表< Person>

我认为只需将代码更改为

I thought that simply changing the code to

Query lQuery = myEntityManager.createQuery("from Person")
List<Person> personList = (List<Person>)lQuery.getResultList();

会工作..但不会。

有办法吗？持久性是否允许我设置查询的返回类型？ （通过泛型可能？）

Is there a way to do this ? Does persistence allow me to set the return type of the query ? (Through generics maybe ? )

推荐答案

作为JPA的新来者把这个作为最终答案，通过此问题：为什么在JPA EntityManager查询中

As a newcomer to JPA was taking this as the definitive answer but then I found a better one via this question: Why in JPA EntityManager queries throw NoResultException but find does not?

它与使用TypedQuery而不是Query一样简单eg：

Its as simple as as using TypedQuery instead of Query e.g.:

TypedQuery<Person> lQuery = myEntityManager.createQuery("from Person", Person.class);
List<Person> personList = lQuery.getResultList();

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