Java USES the File class to traverse directories and file instance code
- 2020-07-21 07:40:29
- OfStack
1. Constructor
File(String args0)// use 1 Creates a string representing a path to a file or directory 1 a File object
File(URL args0)// use 1 a URL Object creation File object
File(File args0, String args1)// use 1 a File object (1 Is a directory ) and 1 A string of filenames was created File object
File(String args0, String args1)// use 1 The directory string and 1 Creates an object with a string of filenames
There are two things to note about using the File class:
First, the File class is used to represent the name, size, and other information of a file or directory and cannot be used to access the contents of a file.
Second, backslashes or double slashes should be replaced in the path of argument passing.
2. Common methods
exists()// Determines whether the current file or directory exists
mkdir()// Create a single level directory, you cannot create multiple levels of directories
mkdirs()// Create multilevel directories
createNewFile()// To create a file with the current path, you need to throw an exception if the path does not exist
delete()// Deletes the current directory or file
isDirectory()// Determine the current File Object directory
isFile()// Determine the current File Whether the object 1 A file
getAbsolutePath()// Returns the absolute path to the current directory or file
getName()// Returns the name of the current directory or file
getParent()// Returns the parent path of the current directory or file
list()// return 1 a String An array of subdirectories and files under the current directory, not including files or directories under the subdirectory
listFiles()// return 1 a File An array of subdirectories and files under the current directory, not including files or directories under the subdirectory
Example 3.
Traverse the directory, printing all directories at all levels.
import java.io.File;
import java.io.IOException;
public class FileTest {
public static void main(String[] args) {
File dir = new File("F:/documents/example");
listDirectory(dir);
}
public static void listDirectory(File dir) {
if (!dir.exists()) {
throw new IllegalArgumentException(" directory " + dir + " There is no ");
}
if (!dir.isDirectory()) {
throw new IllegalArgumentException(dir + " Not a directory ");
}
File[] files = dir.listFiles();
if (files != null && files.length > 0) {
for (File file : files) {
if (file.isDirectory()) {
listDirectory(file);
} else {
System.out.println(file);
}
}
}
}
}