Java uses the list() function of the File class to obtain all file names in the specified directory

Java uses the list() function of the File class to obtain all file names in the specified directory

In Java programming, the File class is one of the core classes used to operate files and directories. It provides a series of methods to create, delete, and rename files and directories, obtain file attributes, determine whether the file exists, etc.

When processing files, sometimes it is necessary to obtain all file names in a specified directory. At this time, you can use the list() function of the File class to implement this function.

Using the list() function of the File class, we can get the names of all files and subdirectories in the specified directory. The following is a simple sample code:

import java.io.File;

public class FileDemo {
    public static void main(String[] args) {
        String dirPath = "C:/Users/User/Desktop";

        File dir = new File(dirPath);

        if (dir.isDirectory()) {
            String[] files = dir.list();
            if (files != null && files.length > 0) {
                System.out.println("指定目录下的所有文件和目录：");
                for (String fileName : files) {
                    System.out.println(fileName);
                }
            } else {
                System.out.println("指定目录下没有文件和目录。");
            }
        } else {
            System.out.println("指定路径不是一个目录。");
        }
    }
}

In this sample code, a string variable dirPath is first declared to store the path to the specified directory. Then use the constructor of the File class to create a File object dir and pass dirPath into it.

Next, determine whether dir is a directory by calling the isDirectory() method. If it is a directory, call the list() function to get the names of all files and subdirectories in the directory.

After obtaining the names of files and directories, then traverse and output these names through a simple for loop.

Finally, some error handling is added. For example, if there are no files or directories in the specified directory, the corresponding prompt information will be output.

It should be noted that the list() function only returns the names of files and subdirectories under the specified directory, and does not include files and subdirectories under the subdirectory. If you need to get all file names recursively, you can use the listFiles() function.

I hope that through this sample code, everyone will have a preliminary understanding of using the list() function of the File class in Java to obtain all file names in a specified directory. In practical applications, appropriate modifications and extensions can be made according to specific needs.

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