问题描述
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?
推荐答案
我发现字段注入只有两个缺点.
I found only two disadvantages in the field injection.
在测试对象时很难注入模拟.(可以使用来自 Mockito 的 @InjectMocks 解决)
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.