Summary of document operations in java (dry cargo)
- 2020-06-07 04:28:54
- OfStack
File class introduction
package com.file;
import java.io.File;
import java.io.IOException;
/**
* Created by elijahliu on 2017/2/10.
*/
public class filetest {
public static void main(String[] args) {
File file = new File("hello.txt");
// If there is a
if (file.exists()) {
// file
System.out.println(file.isFile());
// Path (folder)
System.out.println(file.isDirectory());
File nameto = new File("new Hello.txt");
file.renameTo(nameto);// So here's the renaming of the file, just go ahead and create it 1 a file Object and then use renameTo Method to rename a file
} else {
System.out.println(" File does not exist ");
try {
file.createNewFile();
System.out.println(" The file has been created ");
} catch (IOException e) {
System.out.println(" File cannot be created ");
}
}
if (file.exists()) {
// Delete the file
file.delete();
System.out.println(" Delete the file ");
} else {
}
}
}
Folder operation
package com.file;
import java.io.File;
/**
* Created by elijahliu on 2017/2/11.
*/
public class HelloFolder {
public static void main(String[] args) {
File folder = new File("my new folder");
if (folder.mkdir()) {// Create folder Judge success
System.out.println(" Folder creation completed ");
File newfolder = new File("myn new foleder - new");
folder.renameTo(newfolder);// I renamed the folder here The rename of the folder is to be changed individually 1 Level of folder name And this 1 The folder below level ii remains unchanged Save directory structure
if (folder.delete()) {
System.out.print("done");// The delete here can only delete empty folders, if there is something in the folder, then cannot delete, do not ask 372101 Delete directly 1 A non-empty folder is very irresponsible
} else {
System.out.println("fail");
}
}else{
if (folder.exists()) {
System.out.println(" Folders already exist without being created ");
}else{
System.out.println(" Folder creation failed ");
}
}
File folders = new File("my new folder/one/two/three/main");
folders.mkdirs();// in java using mkdir Can only create 1 A, mkdirs Multiple levels of directories can be created
}
}
File property Settings
package com.file;
import java.io.File;
/**
* Created by elijahliu on 2017/2/11.
*/
public class SetFileProperty {
public static void main(String[] args){
File file = new File("test.file");
if (file.exists()){
file.setWritable(true);// Can write
file.setReadable(true);// Can be read
file.setReadOnly();// read-only
}
}
}
Traversal folder
public void printFiles(File dir,int tab) {//tab Indenting for different directory structures
if (dir.isDirectory()) {
File next[] = dir.listFiles();// Determine if it is a directory Returns an array of all filenames of the directory for traversing the folder
for (int i = 0;i<next.length;i++) {// Hierarchical indent output
System.out.print("---");
}
for(int i = 0;i<next.length;i++) {// This USES recursion to get the directory structure
System.out.println(next[i].getName());
if (next[i].isFile()) {
printFiles(next[i],++tab);
}
}
}
}
Simple file read and write
package com.file;
import java.io.*;
/**
* Created by elijahliu on 2017/2/11.
*/
public class ReadFile {
public static void main(String[] args) {
File file = new File("new Hello.txt");
if(file.exists()){
System.err.print("exsit");
try (FileInputStream fis = new FileInputStream(file)) {// File input stream This is a byte stream
InputStreamReader isr = new InputStreamReader(fis,"UTF-8");//inputstreamReader is 1 Byte stream, byte stream and character stream conversion time, need to be specified 1 A code, or it will be messy
BufferedReader br = new BufferedReader(isr);// Character buffer
String line;
while((line = br.readLine())!=null){// Print out the contents of the buffer if they are not empty
System.out.println(line);
}
br.close();// Finally, the individual threads are closed
isr.close();
fis.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
File newfile = new File("newtext.txt");
try {
FileOutputStream fos = new FileOutputStream(newfile);// Here if the file doesn't exist it will be created automatically
OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF-8");// And read 1 So here's the byte and character streams that are converted
BufferedWriter bw = new BufferedWriter(osw);// Here is the write buffer
bw.write(" Oh my god, you rock! ");// Write string
bw.close();// And the above 1 sample What's open last here is closed first Open first and close later
osw.close();
fos.close();
System.out.println("done");
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}