File type application examples

public  class test1 {
     / * 
     * keyboard input from a folder, the folder size statistics 
     * / 
    public  static  void main (String [] args) { 
        File the dir = the getFile (); 
        . the System OUT .println (getFileLength (the dir)) ; 
    } 
    Private  static  Long getFileLength (File the dir) {
         Long len = 0 ; 
        File [] Farr = dir.listFiles ();
         for (File SUBFILE: Farr) {
             IF (subFile.isFile ()) {
                 len = len +subFile.length (); // file size is the length in bytes 
            }the else{
                len= len +getFileLength (SUBFILE); // recursive folder is encountered at
            }
        }
        returnlen;
    }

    public staticFile the getFile () {// Get keyboard input
        Scanner S1=new newScanner (the System.in);
        . the SystemOUT.println ("Please enter a folder path");
        
        the while(to true) {
            String path=s1.nextLine ();
            file F1=new new File (path);
             IF (f1.exists ()) {
                 IF (f1.isFile ()) { 
                    System. OUT .println ( " you entered is a file path, please re-enter a folder path " ); 
                } the else {
                     return F1; 
                } 
            } the else { 
                . the System OUT .println ( " path you entered is not present, re-enter a folder path " ); 
            } 
        } 
    } 
}

 

 

import java.io.File;

public class test2 {
    
    public static void main(String[] args) {
        File dir = test1.getFile();
        deleteFile(dir);
    }

    private static void deleteFile(File dir) {  //  递归删除文件夹
        File[] subFiles = dir.listFiles();
        for (File subFile : subFiles) {
            if (subFile.isFile()) {
                subFile.delete();
            } else {
                deleteFile(subFile);
            }
        } 
        Dir.delete (); 
    } 

}

 

Import java.io.BufferedInputStream The;
 Import java.io.BufferedOutputStream;
 Import java.io.File;
 Import a java.io.FileInputStream;
 Import java.io.FileNotFoundException;
 Import java.io.FileOutputStream;
 Import java.io.IOException; 

Import javax.swing.text.DefaultEditorKit.CopyAction; 

public  class Test3 {
     / * 
     * 2 files received from the keyboard folder path, the one folder to another folder 
     * / 
    public  static  void main (String [] args) throws IOException { 
        File the src = test1.getFile ();
        File dest = test1.getFile();
        copy(src,dest);
    }

    private static void copy(File src, File dest) throws IOException {
        File newDir = new File(dest,src.getName());
        newDir.mkdir();
        File[] subFiles = src.listFiles();
        for (File subfile : subFiles) {
            if(subfile.isFile()){
                BufferedInputStream b1 = new BufferedInputStream(new FileInputStream(subfile));
                BufferedOutputStream b2 = new BufferedOutputStream(
                        new FileOutputStream(new File(newDir,subfile.getName())));
                int  b;
                while ((b = b1.read()) != -1) {
                    b2.write(b);
                }
                b1.close();
                b2.close();
                
            }else{
                copy(subfile, newDir);
            }
        }
    }

 

Import java.io.File;
 Import java.io.PrintStream; 

public  class Test4 {
     / * 
     * get a folder from the keyboard, in accordance with the print file and folder hierarchy 
     * / 
    public  static  void main (String [] args) { 
        File the dir = test1.getFile (); 
        PrintLev (the dir, 0 ); 
    } 

    public  static  void PrintLev (File the dir, int Lev) { 
        File [] subFiles = dir.listFiles ();
         for (the subfile File: subFiles) {
             for ( int I = 0; i <= lev; i ++) {
                System.out.print("\t");
            }
            System.out.println(subfile);
            if (subfile.isDirectory()) {
                PrintLev(subfile,lev + 1);
            }
        }
    }

}

 

 

import java.io.FileInputStream;

public class test5 {
    /*
     * 斐波那契数列
     */
    public static void main(String[] args) {
        int x = fei(12);
        System.out.println(x);
        int[] arr = new int[12];
        for (int i = 0; i < arr.length; i++) {
            arr[i] = fei(i+1);
            System.out.println(arr[i]);
        }
        
    }

    private static int fei(int n) {
        
        IF (n-n-||. 1 == == 2 ) {
             return . 1 ; 
        } 
        the else {
             return FEI (. 1-n-) + FEI (2-n- ); 
        } 
    } 

}

 

Import java.math.BigInteger; 

public  class test6 {
     / * 
     number of all zero factorial * 1000 and trailing zeros 
     * / 
    public  static  void main (String [] args) {
         // the demo1 ();     // get all 0 
        demo2 ();      // Get tail 0 
    } 

    public  static  void demo2 () { 
        a BigInteger B1 = new new a BigInteger ( ". 1" );
         for ( int I =. 1; I <= 1000; I ++ ) { 
            a BigInteger B2 = new new a BigInteger (I + " " );
            b1 = b1.multiply(b2);
        }
        //System.out.println(b1);
        String str = b1.toString();
        StringBuilder sb1 = new StringBuilder(str);
        str = sb1.reverse().toString();
        int count = 0 ;
        for (int i = 0; i < str.length(); i++) {
            if ('0'!=str.charAt(i)) {
                break;
            } else {
                count++;
            }
            
            
        }
        System.out.println(count);
    }

    public static void demo1() {
        BigInteger b1 = new BigInteger("1");
        for (int i = 1; i <= 1000; i++) {
            BigInteger b2 = new BigInteger(i+"");
            b1 = b1.multiply(b2);
        }
        //System.out.println(b1);
        String str = b1.toString();
        int count = 0 ;
        for (int i = 0; i < str.length(); i++) {
            if ('0'==str.charAt(i)) {
                count= count +1 ;
            }
            
        }
        System.out.println(count);
    }

}