使用 BufferedReader 读取多行整数时出错

Question

我遇到了这个异常：

Exception in thread "main" java.lang.NumberFormatException: For input string: "55 45 65 88 "
    at java.lang.NumberFormatException.forInputString(Unknown Source)
    at java.lang.Integer.parseInt(Unknown Source)
    at java.lang.Integer.valueOf(Unknown Source)

使用此代码时：

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

String line = br.readLine();
int noOfStudents = Integer.parseInt(line); //firstline contains 1 integer.

ArrayList <Integer> marks = new ArrayList<Integer>();

line = br.readLine(); //second line contains a line of integers

StringTokenizer tokens = new StringTokenizer(line, "\\s+");
// to break the line into tokens 

while (tokens.hasMoreTokens())
{
    marks.add(Integer.valueOf(tokens.nextToken())); //error here
    //when I am converting tokens into integers its giving error
}

示例输入：

4
55 45 65 88（这里，当我按下回车键时，会出现上述错误）

Answer 1

StringTokenizer 不支持正则表达式。

StringTokenizer tokens = new StringTokenizer(line, "\\s+");
// This will look for literal "\s+" string as the token.

改用这个，

StringTokenizer tokens = new StringTokenizer(line, " "); // Just a space.

编辑：正如@MasterOdin 所指出的，StringTokenizer 的默认分隔符是空格" "。因此，以下内容也将以相同的方式工作，

StringTokenizer tokens = new StringTokenizer(line);

Answer 2

你可以选择简单的方法：

String []m=br.readLine().split(" "); // split the line delimited with space as array of string.
 for(int i=0;i<m.length;i++){
    marks.add(Integer.valueOf(m[i]));  // add to the marks array list
 }

编辑：根据 T.G

for (String s : br.readLine().split("\\s+")) {
   marks.add(Integer.valueOf(s));
}