Java File IO Operation example

This article is intended to illustrate the basic methods and processes of Java file IO operations as an example.

Source

1 ImportJava.io.*;2 3  Public classMain {4     Final StaticString filename= "Alice.txt";5     //file name6      Public Static voidMain (string[] args) {7         intCount=1;8String dir=system.getproperty ("User.dir");9SYSTEM.OUT.PRINTLN ("The default dir is" +dir);Ten         //Show current Path OneFile file=NewFile (dir+FILENAME); A         Try { - file.createnewfile (); -             //creates a file that has a file with the same name when the CreateNewFile () method is called, and returns false without making a change the}Catch(IOException e) -         { - e.printstacktrace (); -         } +         if(File.exists ()) System.out.println ("The file is exist.")); -         if(File.canread ()) System.out.println ("The file can read. Lenth: "+file.length ()); +         if(File.canwrite ()) System.out.println ("The file can write"); A         //File.delete (); at         //File.getpath (); -         //some practical methods of file -PrintWriter printwriter=NULL; -BufferedWriter bufferedwriter=NULL; -         //do not declare a variable in a try, and the variable will not be accessible in finally -         Try{ inPrintwriter=NewPrintWriter (NewFileOutputStream (FILENAME,false)); -             //If the file does not exist, a new file is created to             //second parameter: Boolean append;true when using "Add Mode", do not create new file, False when creating new file +Printwriter.println (count++ + ":" + "My Name is Alice."); -Printwriter.println (count++ + ":" + "I want to write code."); thePrintwriter.println (count++ + ":" + "I want to having another dance."); *             //Write File $ Panax Notoginseng}Catch(IOException e) -         { the e.printstacktrace (); +         } A         finally { the             if(printwriter!=NULL) + printwriter.close (); -             //Close the stream $         } $BufferedReader bufferedreader=NULL; -         Try -         { theBufferedreader=NewBufferedReader (NewFileReader (FILENAME)); - String what;Wuyi              while(Bufferedreader.ready ()) the{//when there are characters in the stream, read them repeatedly -what=bufferedreader.readline (); Wu System.out.println (what); -             } About             //Read the file $}Catch(IOException e) -         { - e.printstacktrace (); -         } A         finally { +             if(bufferedreader!=NULL) the                 Try { - bufferedreader.close (); $                     //Close the stream the}Catch(IOException e) the                 { the e.printstacktrace (); the                 } -         } in     } the}

Alice.txt file ↑

Console ↑

Java File IO Operation example