英文:
SpringBoot @Autowire why does this example work?
问题
我创建了这个类：
import org.springframework.stereotype.Component;
...
@Component("notTheNameTestMe") // 这应该只对 testMe 起作用吧？
public class TestMe {
public void showMsg() {
System.out.println("自动装配生效了");
}
}
我在第二个类（或者更好的说法是控制器）中这样使用它：
import com.example.TestMe; // 自动装配的话，这个应该不是必需的吧？但是如果不加会报错...
...
@Autowired
private TestMe testMe;
...
this.testMe.showMsg();
但是这个能正常工作（所以也许我这里并没有真正使用自动装配？），甚至如果我将整个 TestMe 类重命名为 TestMeSomething 也能工作（如果我在第二个类中调整导入的话）。
我真的不太明白 @Autowired 是做什么的。我原以为它只是扫描 SpringBoot 组件（通过 @Component() 中的字符串命名），当找到匹配时就注入依赖。但在我的例子中，匹配是不可能的，但我仍然可以在控制台看到 "自动装配生效了" 的消息。如果我真的在这里使用了自动装配，不应该是这样的，对吧？我理解错了什么？与直接使用 new TestMe() 有什么区别呢？我已经通过导入获得了依赖，对吗？所以这不算是真正的依赖注入，对吗？
英文:
I have created this class:
import org.springframework.stereotype.Component;
...
@Component("notTheNameTestMe") //shouldnt this only work with testMe ?
public class TestMe {
public void showMsg() {
System.out.println("Autowiring works");
}
}
And I'm using it this way in a second class (or better: controller):
import com.example.TestMe; //shouldnt this be not necessary with autowire? But getting error else...
...
@Autowired
private TestMe testMe;
...
this.testMe.showMsg();
But this works perfectly (so maybe Im not really using autowire here?), it even works if I rename the whole TestMe class to TestMeSomething (if I adjust the import in the second class)
I dont really understand what @Autowired does. I thought it just scans for SpringBoot Components (which are named by the string in @Component() and when it finds a match it Injects the dependancy. But in my example the match is impossible and I still can see the message "Autowiring works" in the console. This shouldnt be like this if I would really use autowire here or? What am I understanding in a wrong way? What is the difference to using new TestMe() then? I have the dependancy already with the import or? So not a real dependancy injection, or?
答案1
得分: 1
春天并不在 @Component 注解中使用名称。相反，它使用类的名称。它只是在查找名为 TestMe 的类，因为那是您用 @Autowired 注释的变量的类型。
英文:
Spring is not operating on the name in the @Component annotation. Rather it's using the name of the class. It's simply finding a class named TestMe because that's the type of the variable you've annotated with @Autowired.
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论