用JavaConverters替换JavaConversions

Question

当我尝试基于此示例运行代码时,我收到以下警告:

warning: object JavaConversions in package collection is deprecated (since 2.12.0): use JavaConverters

AFAICT,负责警告的线路是:

import scala.collection.JavaConversions._

/* ... */

    for ((k,v) <- environmentVars) println(s"key: $k, value: $v")

用的替换import线

import scala.collection.JavaConverters._

...是不足够的; 单独执行此操作会导致错误:

error: value withFilter is not a member of java.util.Map[String,String]
    for ((k,v) <- environmentVars) println(s"key: $k, value: $v")

还有什么必须做的？

Answer 1

您需要添加asScala方法:

import scala.collection.JavaConverters._

for ((k,v) <- environmentVars.asScala) println(s"key: $k, value: $v")