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问题描述
当我尝试用进程 ID 填充 2D 数组时,我得到 nullpointerexception,它是 2D,因为每个系统都有一个无限的 PID 列表,我最终需要将它返回到我的主代码(现在设置为 void,因为只是一个原型测试函数).
I get nullpointerexception when I try to fill a 2D array with process IDs, it is 2D since there is a unlimited list of PIDs for each system and I need to eventually return that back to my main code (set to void now since just a prototype test function).
任何想法都会很棒
private void testfunctionA (List<String> additionalPC) {
// A 2d array that will contain a list of pids for each system - needs to be strings and not integers
String[][] pidCollection = new String[additionalPC.size()][];
// Go through one system at a time
for (int i=0; i < additionalPC.size(); i++) {
// Get pids for apple per system
String listofpids = Driver.exec("ssh " + additionalPayloads.get(i) + " ps -ef | grep -i apple | grep -v "grep -i apple" | awk \' {print $2}\'");
// Works ok for printing for one system
System.out.println(listofpids);
// put the list of pids into a string array - they are separated by rows
String[] tempPid = listofpids.split("
");
// Put the string array into the 2d array - put this fails with a NPE
for (int j=0; j < tempPid.length; j++) {
pidCollection[i][j] = tempPid[j];
}
System.out.println(pidCollection);
}
推荐答案
您已经创建了二维数组,但数组中充满了 null
一维数组.二维数组中的每个元素都需要创建一个一维数组.您已经使用 tempPid
创建了它;只是使用它.而不是
You've created your 2D array, but the array is full of null
1D arrays. Each element in the 2D array needs to have a 1D array created. You've already created it with tempPid
; just use it. Instead of
for (int j=0; j < tempPid.length; j++) {
pidCollection[i][j] = tempPid[j];
}
就用
pidCollection[i] = tempPid;
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