构造函数注入与字段注入

注入任何服务时，我有两种选择:

When injecting any services, I have two choices :

字段注入:

 @Inject 
 private MyService myService;

或构造函数注入:

private MyService myService; 

@Inject
public ClassWhereIWantToInject(MyService mySerivce){
    this.myService = myService;
}

为什么构造函数注入优于字段注入?

我发现字段注入只有两个缺点.

I found only two disadvantages in the field injection.

循环依赖.如果 bean A 依赖于 bean B 并且 bean B 需要 bean A.如果你有构造函数注入很容易找到它.

Circle dependencies. If bean A depends on bean B and bean B needs bean A. If you have the constructor injection it easy to find it.

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