java - 调用 .next() 方法时扫描仪出现 NoSuchElementException

Question

在 Java 中，我收到此异常:

Exception in thread "main" java.util.NoSuchElementException
    at java.util.Scanner.throwFor(Unknown Source)
    at java.util.Scanner.next(Unknown Source)
    at com.reading.text.Activity3.readFile(Activity3.java:22)
    at com.reading.text.Activity3.main(Activity3.java:10)

来自此 Java 代码:

public static void main(String args[])
{
    readFile("C:/Users/forsakendoll/Desktop/boom.txt");
}

public static void readFile(String path) {
    Scanner file = null;
    try {
        file = new Scanner(new File (path));
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } finally {
        while (file.hasNext()) {
            for(int counter = 0 ; counter < file.next().length(); counter ++) {
                System.out.println(file.next().charAt(counter));    
            }
        }
    }
}

抛出异常

System.out.println(file.next().charAt(counter));

异常是什么意思？

Answer 1

您在循环的每次迭代中都会调用 .next() 两次，因此当您接近末尾时，您会跳出列表的末尾，编译器会告诉您那里没有任何内容.

而不是这个:

for(int counter = 0 ; counter < file.next().length(); counter ++) {
    System.out.println(`file.next()`.charAt(counter));    
}

这样做:

String temp = file.next();
for(int counter = 0 ; counter < next.length(); counter ++) {
    System.out.println(temp .charAt(counter));    
}  

SEE HERE