java - 这个文件扫描器代码有什么问题？

Question

我正在尝试在文件中搜索 Java 语言的字符。为此，我正在使用 Scanner扫描文件。

为了检查层次结构工作，我正在使用 System.out.print("Worked till here!");这样我就可以检查它是否被执行。我能够执行代码直到最后阶段，但后来我发现必不可少的boolean变量没有被改变，这是在检查是否有字符匹配的情况下的。

文件内容如下

Ok, here is some text!

Actually this file is created to test the validity of the java application

Java is my favourite programming language.

And I think I can score even more :)

Wish me luck!

但是，无论我搜索什么，它总是提示我 false .

这是我正在使用的代码

public static void main (String[] args) throws IOException {
    // Only write the output here!!!
    System.out.print("Write the character to be found in the File: ");
    Scanner sc = new Scanner(System.in);
    String character = sc.next();
    // Find the character
    System.out.println("Searching now...");
    getCharacterLocation(character);
    // Close the resource!
    sc.close();
    
}

执行的方法调用，方法如下

public static void getCharacterLocation (String character) throws IOException {
    System.out.println("File found...");
    File file = new File("res/File.txt");
    Scanner sc = new Scanner(file);
    int lineNumber = 0;
    int totalLines = 0;
    boolean found = false;
    // First get the total number of lines
    while(sc.hasNextLine()) {
        totalLines++;
        sc.nextLine();
        System.out.println("Line looping! For Total Lines variable.");
    }
    int[] lineNumbers = new int[totalLines];
    int lineIndex = 0;
    System.out.println("Searching in each line...");
    while(sc.hasNextLine()) {
        // Until the end
        /* Get each of the character, I mean string from
         * each of the line... */
        while(sc.hasNext()) {
            // Until the end of line
            String characterInLine = sc.next();
            if(sc.findInLine(character) != null) {
                found = true;
            }
        }
        System.out.print(sc.nextLine() + "\n");
        lineNumber++;
        sc.nextLine();
    }
    System.out.println("Searching complete, showing results...");
    // All done! Now post that.
    if(found) {
        // Something found! :D
        System.out.print("Something was found!");
    } else {
        // Nope didn't found a fuck!
        System.out.println("Sorry, '" + character + 
                    "' didn't match any character in file.");
    }
    sc.close();
}

不用介意变量和数组的额外使用。如果我可以获取该字符并将该值设置为 true，我将在进一步编码中使用它。

这是该程序的输出。

初始阶段

这是初始阶段。我写了Ok在输入字段中，您可以看到 Ok也是文件中的第一个字符。

最后阶段

这是执行后的结果。

这方面有什么帮助吗？

Answer 1

您计算行数并且不重新启动扫描仪。

boolean found = false;
// First get the total number of lines
while(sc.hasNextLine()) {
    totalLines++;
    sc.nextLine();
    System.out.println("Line looping! For Total Lines variable.");
}
int[] lineNumbers = new int[totalLines];
int lineIndex = 0;
System.out.println("Searching in each line..."); // <------
while(sc.hasNextLine()) {

添加例如

根据评论更新

sc.close();
sc = new Scanner(file); 

在下一个while(sc.hasNextLine())

之前