Question

我使用scala处理嵌套的json

"disks" : [ {
"name" : "v2.16",
"diskAggregate" : "aggr0",
"diskRPM" : 15000,
"totalSizeBytes" : 1077477376,
"vendorId" : "NETAPP  ",
"usedBytes" : 1070071808,
"diskType" : "FCAL",
"uuid" : "4E455441:50502020:56442D31:3030304D:422D465A:2D353230:32353836:30303030:00000000:00000000",
"portName" : "FC:A ",
"raidGroup" : "rg0"
}, 
{
"name" : "v4.16",
"diskAggregate" : "aggr0",
"diskRPM" : 15000,
"totalSizeBytes" : 1077477376,
"vendorId" : "NETAPP  ",
"usedBytes" : 1070071808,
"diskType" : "FCAL",
"uuid" : "4E455441:50502020:56442D31:3030304D:422D465A:2D353230:32353633:34333030:00000000:00000000",
"portName" : "FC:B ",
"raidGroup" : "rg0"
}]

我希望获得“使用过的”这些＆＃39;在json数组的所有json对象中。如何获得“usedBytes”的总和？从json上面使用scala ??

修改

这是我试过的

val datastoreCapacity = disks
val usableSpace = datastoreCapacity.foldLeft(0L) {
case (sumOfUsedSpace, esxDevice) =>
  val sumOfTotalBytesOnStorageDevice = esxDevice.datastores.foldLeft(0L) {
    case (totalBytesOnDevice, datastore) =>
     // totalBytesOnDevice + ut..getOrElse(0L).toString.toLong
    val sum = datastore.utilization.foldLeft(0L) {
      case (total,util) =>
        total + util.usedBytes.getOrElse(0L).toString.toLong
    }
  }
  sumOfUsedSpace + sumOfTotalBytesOnStorageDevice
 }

Answer 1

在下面的foldLeft（B）中，最后一个表达式是一个赋值（注释掉），它返回Unit。

val datastoreCapacity = disks
val usableSpace = datastoreCapacity.foldLeft(0L) { // A

    case (sumOfUsedSpace, esxDevice) =>
         val sumOfTotalBytesOnStorageDevice = esxDevice.datastores.foldLeft(0L) { // B

             case (totalBytesOnDevice, datastore) =>
                   // totalBytesOnDevice + ut..getOrElse(0L).toString.toLong
                   /* Note --> val sum = */ // assignment returns Unit
                   datastore.utilization.foldLeft(0L) { // C

                       case (total,util) =>
                            total + util.usedBytes.getOrElse(0L).toString.toLong
                   }

         }
         sumOfUsedSpace + sumOfTotalBytesOnStorageDevice
}

如何使用scala获取嵌套json中的元素总和？

1 个答案: