8.26 ~ 9.1 weekly summary

This week the focus is placed on learning operating Java files.

Learning as follows:

Created in the specified location of a file, directory and create a txt file, and output statements to determine whether to create success.

Package File file type operation; 

Import java.io.File;
 Import java.io.IOException; 

public  class Demo1 { 
    
    public  static  void main (String [] args) throws IOException {// thrown 
            
        File File = new new File ( "D : // java directory created " );
         boolean b = file.mkdir (); // create a virtual directory 
        IF (b) { 
            System.out.println ( !" directory successfully created " ); 
            File = new new File (" d : // // create the directory java java file created .txt " );
             boolean b2 =file.createNewFile ();
             IF (b2) { 
                System.out.println ( "File successfully created!" ); 
            } 
            the else { 
                System.out.println ( "File creation failed!" ); 
            } 
        } the else { 
            System.out. println ( "directory creation failed!" ); 
        } 
    } 

}

Delete operations:

You must delete the files inside of something, and then delete the file itself, if the file inside the thing, you can not delete the operation. Delete only an empty file.

Package File file type operation; 

Import java.io.File;
 Import java.io.IOException; 

public  class Demo2 { 
    
    public  static  void main (String [] args) throws IOException { 
        File File = new new File ( "D: // Create Java // directory file .txt "java created );
         IF (File.Exists ()) {   // If the file exists 
        boolean b = File.delete (); // delete the file 
        IF (b) { 
            System.out.println ( "delete file successfully" ); 
        } the else { 
            System.out.println ("Failed to delete file" ); 
        } 
        } 
        File = new new File ( "d: // java directory created" );
         IF (File.Exists ()) { 
            File.delete (); // delete directory 
            boolean b2 = File. the delete ();
              IF (b2) { 
                 System.out.println ( "successfully remove a directory ..." ); 
             } the else { 
                 System.out.println ( "delete directory failed." ); 
             } 
            } 
    } 
}

Traverse directories:

The output out of the files in the directory:

Package File file type operation; 

Import java.io.File; 

public  class Demo3 { 
    
    public  static  void main (String [] args) { 
        File File = new new File ( "D: \\ c \\ c Language Language Information" ); 
        File Files [] = File.listFiles (); // traverse the directory 
        for ( int I = 0; I <files.length; I ++ ) { 
            System.out.println (Files [I]); 
        } 
    } 

}

Perform the operation results are as follows:

 

 

 

Reading and writing files:

output stream reader 

writer for the input stream  

After each new input and output streams must be operated by a respective closing created.

Two kinds of ways to read the file:

1 .
 // all at once have been read out and output 
Package File File Class Action 2; 

Import java.io.File;
 Import java.io.FileReader;
 Import a java.io.Reader; 

public  class file read and write operations { 
    
    public  static  void main (String [] args) throws Exception { 
        File File = new new File ( "D: //cxy.txt" ); 
        Reader Reader = new new the FileReader (File);
         char C [] = new new  char [1024];   // character array 
        int len = reader.Read (C);
        reader.Close ();   // Close the input stream 
        System.out.println ( "details:" + new new String (C, 0 , len)); 
    } 

}
 2 .
 // the file reads and outputs data individually 
Package file file class Action 2; 

Import java.io.File;
 Import java.io.FileReader;
 Import a java.io.Reader; 

public  class file read and write operations {2 
    
    
    public  static  void main (String [] args) throws Exception { 
        file File = new new File ( "D: //cxy.txt" ); 
        Reader Reader = new newThe FileReader (File);
         char C [] = new new  char [1024];   // array of characters 
        int TEMP = 0 ;
         int len = 0 ;
         the while (! (Reader.Read TEMP = ()) = -. 1) {    // a reading a 
            C [len ++] = ( char ) TEMP; 
            
        } 
        reader.Close ();   // Close the input stream 
        System.out.println ( "details:" + new new String (C, 0 , len)); 

} 
}

Overwriting files:

The original data file covering the entire re-enter data

Package File File Class Action 2; 

Import java.io.File;
 Import java.io.FileNotFoundException;
 Import java.io.FileOutputStream;
 Import a java.io.OutputStream; 

public  class Demo3 { 

    public  static  void main (String [] args) throws {Exception 
        File File = new new File ( "D: // Baidu network disk //cxy.txt" ); 
        OutputStream OUT = new new FileOutputStream (File); 
        String str = "I could not help my life by the day, is a magic fairy to me a small count us ";   // cover 
        byte B [] = str.getBytes ();
        out.write (B);   // array to the output stream 
        the out.close ();    // Close the output stream 
    } 
}

File append mode:

Before data does not cover, add new information to the end

Package File File Class Action 2; 

Import java.io.File;
 Import java.io.FileOutputStream;
 Import a java.io.OutputStream;
 / ** 
 * append file 
 * @author cuixingyu 
 * 
 * / 

public  class Demo4 { 
    
    public  static  void main ( String [] args) throws Exception { 
        File File = new new File ( "D: // Baidu network disk //cxy.txt" ); 
        the OutputStream OUT = new new a FileOutputStream (File, to true ); 
        String STR = "my life that I could not help day, magic fairy is for me to say 4785 ";  // append mode 
        byte B [] = str.getBytes (); 
        out.write (B);   // array to the output stream 
        the out.close ();    // Close the output stream 

} 
}