错误 java.lang.NumberFormatException：对于输入字符串：“”
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Error java.lang.NumberFormatException: For input string: ""
提问by ArCiGo
I'm trying to read this file
我正在尝试读取此文件
C101
VEHICLE
NUMBER CAPACITY
25 200
CUSTOMER
CUST NO. XCOORD. YCOORD. DEMAND READY TIME DUE DATE SERVICE TIME
0 40 50 0 0 1236 0
1 45 68 10 912 967 90
2 45 70 30 825 870 90
3 42 66 10 65 146 90
4 42 68 10 727 782 90
5 42 65 10 15 67 90
6 40 69 20 621 702 90
7 40 66 20 170 225 90
8 38 68 20 255 324 90
But when I read the file, the program throws me this exception:
但是当我读取文件时，程序抛出了这个异常：
Exception in thread "main" java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:504)
at java.lang.Integer.parseInt(Integer.java:527)
at VRP.main(VRP.java:43)
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)
I cheked my code and debugged, but I can't find the problem.
我检查了我的代码并进行了调试，但我找不到问题所在。
I used an array to save all the spaces between the columns (I only read the first four columns) and then an ArrayList but it doesn't worked.
我使用了一个数组来保存列之间的所有空格（我只读取了前四列），然后是一个 ArrayList 但它不起作用。
public static void main(String[] args) throws Exception {
File f = new File("C101.txt");
FileReader fr = new FileReader(f);
BufferedReader reader = new BufferedReader(fr);
String nada = reader.readLine(); //C101
nada = reader.readLine(); //espacio en blanco
nada = reader.readLine(); //vehicle=25
nada = reader.readLine(); //number, capacity
nada = reader.readLine(); //25, 200
nada = reader.readLine(); //espacio en blanco
nada = reader.readLine(); //customer
nada = reader.readLine(); //encabezados
nada = reader.readLine(); //espacio en blanco
String[] espacios;
int capacity = 200;
int custno, xcoord, ycoord, demand;
ArrayList<String> guardar = new ArrayList<String>();
while (reader.ready()) {
espacios = reader.readLine().trim().split(" ");
for (int i = 0; i < espacios.length; i++) {
guardar.add(espacios[i]);
}
custno = Integer.parseInt(espacios[0]);
xcoord = Integer.parseInt(espacios[1]);
ycoord = Integer.parseInt(espacios[2]);
demand = Integer.parseInt(espacios[3]);
}
}
Sorry for the inconvenient and thank you for your time.
很抱歉给您带来不便，感谢您抽出宝贵时间。
回答by La-comadreja
You got to make sure that espacios[0]through espacios[3]are actually integers. What you should probably do is print them out to check. If one of them isn't an integer, Integer.parseInt()will throw that exception.
你必须确保espacios[0]通过espacios[3]实际上是整数。您可能应该做的是将它们打印出来进行检查。如果其中一个不是整数，Integer.parseInt()将抛出该异常。
回答by Reimeus
You're splitting on a single space but there is more than one space between the integer columns
您在一个空格上拆分，但整数列之间有多个空格
espacios = reader.readLine().trim().split("\s+");
