Home>
•file class
1. It is only used for information (name, size, etc.) indicating a file (directory), and cannot be used to access the contents of the file.
package cn.test;
import java.io.file;
import java.io.ioexception;
public class demo16 {
public static void main (string [] args) {
file file=new file ("f:\\ javaio");
//Whether the file (directory) exists
if (! file.exists ()) {
//Create a directory
file.mkdir ();//file.mkdirs ();
} else {
//File (directory) delete
file.delete ();
}
//Whether it is a directory Returns true if it is a directory, false if it is not a directory or the directory does not exist
system.out.println (file.isdirectory ());
//whether it is a file
system.out.println (file.isfile ());
//file file2=new file ("f:\\ java \\diary 1.txt");
file file2=new file ("f:\\ javaio", "Diary 2.txt");
if (! file2.exists ()) {
try {
//Create a file
file2.createnewfile ();
} catch (ioexception e) {
e.printstacktrace ();
}
} else {
file2.delete ();
}
system.out.println (file);
system.out.println (file.getabsolutepath ());//Return the absolute path
system.out.println (file.getname ());//directory name
system.out.println (file2.getname ());//file name
system.out.println (file.getparent ());//The path to the parent directory
system.out.println (file.getparent ());//The path to the parent directory
}
}
2. Traversing the directory
package com.test.io;
import java.io.file;
import java.io.ioexception;
/**
* Common operations of the file class
* @author administrator
*
* /
public class fileutils {
/**
* List all files in the specified directory (including its subdirectories)
* @param dir
* @throws ioexception
* /
public static void listdirectory (file dir) throws ioexception {
if (! dir.exists ()) {
throw new illegalargumentexception ("directory" + dir + "does not exist");
}
if (! dir.isdirectory ()) {
throw new illegalargumentexception (dir + "Not a directory");
}
/* string [] filenames=dir.list ();//An array of strings is returned,List subdirectories and files in the current directory (not including the contents of subdirectories)
for (string string:filenames) {
system.out.println (dir + "\\" + string);
} * /
//If i want to traverse the contents of the subdirectory,You need to construct the file object for recursive operations
file [] files=dir.listfiles ();//Returns the abstraction of direct subdirectories (files)
if (files!=null&&files.length>0) {
for (file file:files) {
if (file.isdirectory ()) {
//recursive
listdirectory (file);
} else {
system.out.println (file);
}
}
}
}
}
Related articles
- Detailed File type representing a file in java
- Detailed and simple examples of the Java File class
- Talk about the differences between the File class getPath (), getAbsolutePath (), and getCanonical in Java
- IO Stream RandomAccessFile class instance in Java
- Java uses the File class to traverse directories and file instance code
- Java uses RandomAccessFile class to read and write files
- Summary of basic usage of java File class
- Summary of common methods of the Java File class
- Detailed explanation of common methods in the File class in Java
Trends