File Class String []列表(FilenameFilter fnf) (File Class String[] list(FilenameFilter fnf))

• This method is available in package java.io.File.list(FilenameFilter fnf).

  軟件包java.io.File.list(FilenameFilter fnf)中提供了此方法。

• This method is used to return the names of all the files in the form of an array of strings which is represented in the filepath.

  此方法用于以字符串數組的形式返回所有文件的名稱，這些字符串以文件路徑表示。

• The return type of this method is String[] i.e. It returns an array of strings of all the files or directories which is represented in filepath if the given path is directory else return null.

  此方法的返回類型為String []，即，如果給定路徑為目錄，則返回文件路徑中表示的所有文件或目錄的字符串數組，否則返回null。

• This method may raise an exception( i.e. Security Exception) if the write access is not given to the file.

  如果未授予文件寫入權限，則此方法可能會引發異常(即Security Exception)。

• This method is overridable. The first method does not accept any parameter and the second method accept one parameter.

  此方法是可重寫的。 第一種方法不接受任何參數，第二種方法則接受一個參數。

Syntax:

句法：

String[] list(){}

Parameter(s):

參數：

We pass only one object FilenameFilter as a parameter in the method and with the help of this argument, we can find files with filter(i.e we can find specific files).

我們僅傳遞一個對象FilenameFilter作為方法中的參數，借助此參數，我們可以找到帶有filter的文件(即，可以找到特定的文件)。

Return value:

返回值：

The return type of this method is String[] i.e. it returns all files names in an array of strings which is represented in a filepath.

此方法的返回類型為String []，即它以文件路徑表示的字符串數組形式返回所有文件名。

Java程序演示list()方法的示例 (Java program to demonstrate example of list() method)

// import the File class because we will use File class methods import java.io.*;// import the Exception class because it may raise an // exception when working with files import java.lang.Exception;public class ToListSpecificFiles {public static void main(String[] args) {try {// Specify the path of file and we use double slashes to // escape '\' character sequence for windows otherwise // it will be considerable as url.File file = new File("C:\\Users\\computer clinic\\OneDrive\\Articles");// Create a FilenameFilter objectFilenameFilter fnf = new FilenameFilter() {public boolean accept(File file, String name) {return name.startsWith("J");}};// By using list(fnf) returns all the files and directories // which is represented in a file path if file path is a // directory and all file or directories starts with 'J'.String[] filelist = file.list(fnf);System.out.println("These are the name of files represented in a given directory :" + file.getPath());// By using loop to traverse the filenames and directories // in the given path .for (int i = 0; i < filelist.length; i++)System.out.println(filelist[i]);} catch (Exception e) {System.out.println("An error occurred.");e.printStackTrace();}} }

Output

輸出量

D:\Programs>javac ToListSpecificFiles.javaD:\Programs>java ToListSpecificFiles These are the name of files represented in a given directory :C:\Users\computer clinic\OneDrive\Articles Java File Class canExecute().docx Java File Class canRead().docx Java File Class canWrite().docx

翻譯自: https://www.includehelp.com/java/file-class-string-list-filenamefilter-fnf-method-with-example.aspx

總結

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