如何在 kotlin 中使用像 @Autowired 这样的 spring 注释? [英] How to use spring annotations like @Autowired in kotlin?
问题描述
是否可以在 Kotlin 中执行类似以下操作?
Is it possible to do something like following in Kotlin?
@Autowired
internal var mongoTemplate: MongoTemplate
@Autowired
internal var solrClient: SolrClient
推荐答案
推荐在 Spring 中进行依赖注入的方法是构造函数注入:
Recommended approach to do Dependency Injection in Spring is constructor injection:
@Component
class YourBean(
private val mongoTemplate: MongoTemplate,
private val solrClient: SolrClient
) {
// code
}
在 Spring 4.3 之前的构造函数应该用 Autowired 显式注释:
Prior to Spring 4.3 constructor should be explicitly annotated with Autowired:
@Component
class YourBean @Autowired constructor(
private val mongoTemplate: MongoTemplate,
private val solrClient: SolrClient
) {
// code
}
在极少数情况下，您可能喜欢使用字段注入，您可以借助 lateinit 来实现:
In rare cases, you might like to use field injection, and you can do it with the help of lateinit:
@Component
class YourBean {
@Autowired
private lateinit var mongoTemplate: MongoTemplate
@Autowired
private lateinit var solrClient: SolrClient
}
构造函数注入在bean创建时检查所有依赖项，所有注入的字段都是val，另一方面，lateinit注入的字段只能是var，并且运行时开销很小.用构造函数测试类，你不需要反射.
Constructor injection checks all dependencies at bean creation time and all injected fields is val, at other hand lateinit injected fields can be only var, and have little runtime overhead. And to test class with constructor, you don't need reflection.
链接:
这篇关于如何在 kotlin 中使用像 @Autowired 这样的 spring 注释?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
