KafkaProducer类型的表达式[字符串，字符串]不符合期望的类型空

Question

我希望能够从函数setProducer初始化变量producer。

object MyObj { 
    var producer = null                             

    def setProducer(p: KafkaProducer[String,String]): Unit = {   
    producer = p              
    } 

    //... 
} 

但是它说的是Expression of type KafkaProducer[String,String] doesn't conform to expected type Null。

那么，我该如何初始化producer？

Answer 1

您需要提供的变量类型，例如：

object MyObj { 
    var producer: KafkaProducer[String,String] = null                             

    def setProducer(p: KafkaProducer[String,String]): Unit = {   
    producer = p              
    } 

    //... 
}