本文介绍了Java多维数组因nullpointerException失败的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
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,因为每个系统都有无限制的PID列表,我最终需要将其返回到我的主代码(从现在开始设置为void只是一个原型测试功能).
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("\n");
// 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2D数组,但是该数组充满了 null
一维数组.2D数组中的每个元素都需要创建一个1D数组.您已经使用 tempPid
创建了它;只是使用它.代替
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];
}
只需使用
pidCollection[i] = tempPid;
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