Java 缺少 CrudRepository#findOne 方法
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Missing CrudRepository#findOne method
提问by Andrii Abramov
I am using Spring 5 in my project. Until today there was available method CrudRepository#findOne.
我在我的项目中使用 Spring 5。直到今天才有可用的方法CrudRepository#findOne。
But after downloading latest snapshot it suddenly disappeared! Is there any reference that the method is not available now?
但是下载最新的快照后它突然消失了！是否有任何参考该方法现在不可用？
My dependency list:
我的依赖列表：
apply plugin: 'java'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
repositories {
mavenCentral()
maven { url "https://repo.spring.io/snapshot" }
maven { url "https://repo.spring.io/milestone" }
}
dependencies {
compile 'org.springframework.boot:spring-boot-starter-data-jpa'
runtime 'com.h2database:h2:1.4.194'
}
UPDATE:
更新：
Seems that this method has been replaced with CrudRepository#findById
似乎这种方法已被替换为 CrudRepository#findById
采纳答案by Sean Carroll
Please see DATACMNS-944which is associated to this commitwhich has the following renames
请参阅与此提交相关联的DATACMNS-944，该提交具有以下重命名
╔═════════════════════╦═══════════════════════╗
║ Old name ║ New name ║
╠═════════════════════╬═══════════════════════╣
║ findOne(…) ║ findById(…) ║
╠═════════════════════╬═══════════════════════╣
║ save(Iterable) ║ saveAll(Iterable) ║
╠═════════════════════╬═══════════════════════╣
║ findAll(Iterable) ║ findAllById(…) ║
╠═════════════════════╬═══════════════════════╣
║ delete(ID) ║ deleteById(ID) ║
╠═════════════════════╬═══════════════════════╣
║ delete(Iterable) ║ deleteAll(Iterable) ║
╠═════════════════════╬═══════════════════════╣
║ exists() ║ existsById(…) ║
╚═════════════════════╩═══════════════════════╝
回答by Do Nhu Vy
A pragmatic transform
务实的转变
Old way:
旧方式：
Entity aThing = repository.findOne(1L);
New way:
新方法：
Optional<Entity> aThing = repository.findById(1L);
回答by Tinus Tate
Note that findByIdis not an exact replacement for findOne, it returns an Optionalinstead of null.
请注意，这findById不是 的精确替代品findOne，它返回一个Optional而不是null。
Being not very familiar with new java things it took me a little while to figure out, but this turns the findByIdbehavior into the findOneone:
由于对新的 Java 事物不是很熟悉，我花了一些时间才弄明白，但这将findById行为变成了findOne这样：
return rep.findById(id).orElse(null);
回答by ashario
We had many hundreds of usages of the old findOne()method. Rather than embark on a mammoth refactor, we ended up creating the following intermediary interface and had our repositories extend it instead of extending JpaRepositorydirectly
我们有数百种旧findOne()方法的用法。我们没有进行大规模的重构，而是创建了以下中间接口，并让我们的存储库扩展它而不是JpaRepository直接扩展
@NoRepositoryBean
public interface BaseJpaRepository<T, ID> extends JpaRepository<T, ID> {
default T findOne(ID id) {
return (T) findById(id).orElse(null);
}
}
