该文件对象是否保持打开状态? [英] Is this file object left open?

问题描述

作为学校的一项练习，我用Java编写了一种在文件中搜索字符的方法.这是代码:

As an exercise for school I wrote a method in Java that searches for a character in a file. Here is the code:

 public static void countLetter(char needle, String hayStack) throws IOException {

        File f = new File(hayStack);                                           
        try (Scanner in = new Scanner(f)) {                                    
            String str = null;                                                 
            while (in.hasNext()){                                              
                str += in.next();                                              
            }                                                                  
            char[] charArr = str.toCharArray();                                
            int counter = 0;                                                   
            for (char c: charArr) {                                            
                if (c == needle){                                              
                    counter++;                                                 
                }                                                              
            }                                                                  
            System.out.println(counter);                                       
        }                                                                      
    }

这可以满足我的需求，但是我有一个问题. 文件对象是否曾经打开过? 我是否在Scanner对象上使用了try-with-resources，所以我很确定不必显式关闭它，但是文件对象呢? >

This does what I need it to but I have a question. Is the file object ever opened? And if it is, does it ever closed? I used try-with-resources on the Scanner object so I'm pretty sure I don't have to explicitly close that, but what about the file object?

推荐答案

文件对象只是路径名的抽象表示，与打开文件无关.因此它无法关闭.

File object is just an abstract representation of a pathname, it has nothing to do with opening a file. So it can not be closed.

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