使用Scanner类从文件读取信息时遇到问题

Question

I wrote this simple program to try to read information from a txt file in my computer's D drive`

package readDisk;
import java.nio.charset.StandardCharsets;
import java.nio.file.*;
import java.util.*;

public class ReadDisk 
{
    public static void main(String[] args) {
    Scanner input = new Scanner(Path.of("D:\\test.txt"), StandardCharsets.UTF_8);
    String TestText = input.nextLine();
    System.out.println(TestText);
    }
}

I am getting an error message upon compilation which goes

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
    The method of(String) is undefined for the type Path

    at readDisk.ReadDisk.main(ReadDisk.java:9)

I am following a sample program found in the 11th Edition of Core Java Volume 1 and I've looked all over, trying to find where I've gone wrong to no avail. Any help will be appreciated.

Answer 1

As opposed to what some commenters say, the method you're trying to use does actually exist . The method in question takes a required first argument, and then a variable number of arguments, effectuated by the varargs construct , which means zero or more arguments.

But it is only available from Java 11 onwards. You need to check your Java version.

An alternative would be that you use scanner with another argument:

• new Scanner(new File(D:/test.txt), StandardCharsets.UTF_8) ; or
• new Scanner(Paths.get(D:/test.txt), StandardCharsets.UTF_8)

The constructors throw a FileNotFoundException and an IOException respectively. Make sure you either handle it or propagate it to the caller.

---

^{Note: A quick local test has shown me that this actually works for me. So if your code still throws a FileNoteFoundException , my guess is there is something otherwise wrong with the file or filename.}

Answer 2

尝试按以下方式初始化扫描仪，您无需为此设置Path：

Scanner input = new Scanner(new File("D:\\test.txt") , StandardCharsets.UTF_8);

Answer 3

The Path.of() method, added in JDK 11, requires a URI as parameter, not a String . For example,

Scanner input = new Scanner(Path.of(new URI("file:///D:/test.txt")), StandardCharsets.UTF_8);

Or you can simply use new Scanner(File) , as other answer said.

Answer 4

Your code is fine Path::of method can take only one argument since the second one is vararg. Just make sure you are using java 11