如何将@autowired构造函数参数单独设置为“required=false”

Question

我正在@configuration类构造函数下使用@autowired注释。

@Configuration
public class MyConfiguration {

   private MyServiceA myServiceA;
   private MyServiceB myServiceB

   @Autowired
   public MyConfiguration(MyServiceA myServiceA, MyServiceB myServiceB){
     this.myServiceA = myServiceA;
     this.myServiceB = myServiceB;    
   }
}

正如Spring文档所说的，我能够声明是否需要带注释的依赖项。

@Autowired(required = false)
public MyConfiguration(MyServiceA myServiceA, MyServiceB myServiceB){
  this.myServiceA = myServiceA;
  this.myServiceB = myServiceB;   
}

如何将required属性单独设置为每个构造函数参数？是否需要在每个字段下使用@autowired注释？

问候,

Answer 1

如果您使用的是Java8和Spring Framework4，那么就可以使用optional。

@Autowired
public MyConfiguration(Optional<MyServiceA> myServiceA, Optional<MyServiceB> myServiceB){
  myServiceA.ifPresent(service->{this.myServiceA = service});
  myServiceB.ifPresent(service->{this.myServiceB = service});   
}