Kjava local file read/write demo

Import java. Io. ioexception;
Import java. Io. inputstream;
Import java. Io. outputstream;

Import javax. microedition. Io. connector;
Import javax. microedition. Io. file. fileconnection;
Import javax. microedition. lcdui. Command;
Import javax. microedition. lcdui. commandlistener;
Import javax. microedition. lcdui. display;
Import javax. microedition. lcdui. displayable;
Import javax. microedition. lcdui. form;
Import javax. microedition. lcdui. stringitem;
Import javax. microedition. lcdui. textfield;
Import javax. microedition. MIDlet. MIDlet;
Import javax. microedition. MIDlet. midletstatechangeexception;

Public class fileoperations extends MIDlet implements commandlistener {
Form = new form ("fileoperations ");

Stringbuffer sb = new stringbuffer ();

String filepath = "file: // E:/1.txt"; // the path of the file to be read and written, such as Sony Ericsson and Nokia.

// String filepath = "file: // root1/1.txt"; // file path simulator to be read/written

// Stringitem Si = new stringitem (null, "data to be written :");

Stringitem info = new stringitem (null, null );

Textfield TF = new textfield ("data to be written", "test", 100, textfield. Any );

Command exit = new command ("exit", command. Exit, 1 );

Command write = new command ("Write File", command. OK, 1 );

Command READ = new command ("Read File", command. OK, 1 );

Public fileoperations (){

// Form. append (SI );
Form. append (TF );
Form. addcommand (write );
Form. addcommand (read );
Form. addcommand (exit );
Form. setcommandlistener (this );
}

Protected void destroyapp (Boolean arg0 ){

}

Protected void pauseapp (){

}

Protected void Startapp () throws midletstatechangeexception {
Display. getdisplay (this). setcurrent (form );

}

/**
* Add text
*
* @ Param Str
* Text to be added
*/
Private void addstr (string Str ){
SB. append (STR + "/N ");
Info. settext (sb. tostring ());
}

/**
* Write a file
*
* @ Param B
*/
Private void write (byte [] B ){
Addstr ("path" + filepath );
Write (filepath, B );
}

Private void write (string path, byte [] B ){
Addstr ("Write File ");
Fileconnection fc = NULL;
Outputstream OS = NULL;
Try {
Fc = (fileconnection) connector. Open (PATH );

If (! FC. exists () // if the file does not exist
FC. Create (); // create a file
Else
FC. truncate (0); // clear file data

OS = FC. openoutputstream ();
OS. Write (B); // Write File data
OS. Close ();
OS = NULL;
Addstr ("completed file writing ");
FC. Close ();
Fc = NULL;

} Catch (ioexception e ){
E. printstacktrace ();
Addstr ("file writing exception" + E. tostring ());

} Catch (securityexception e ){
E. printstacktrace ();
Addstr ("permission error during file writing ");

} Finally {
If (OS! = NULL ){
Try {
OS. Close ();
} Catch (ioexception e ){
E. printstacktrace ();
}
OS = NULL;
}

If (FC! = NULL ){
Try {
FC. Close ();
} Catch (ioexception e ){
E. printstacktrace ();
}
Fc = NULL;
}

}

}

/**
* Read files
*
*/
Private void read (){
Addstr ("path" + filepath );
Read (filepath );
}

Private void read (string path ){
Addstr ("Read File ");
Fileconnection fc = NULL;
Inputstream is = NULL;
Try {
Fc = (fileconnection) connector. Open (PATH );

If (! FC. exists () {// if the file does not exist
Addstr ("file does not exist ");
Return;
}

Is = FC. openinputstream ();
Byte [] B = new byte [(INT) FC. filesize ()];
Is. Read (B); // read the file data
Addstr ("File Content :");
Addstr (new string (B ));
Addstr ("finished reading the file ");
Is. Close ();
Is = NULL;
FC. Close ();
Fc = NULL;

} Catch (ioexception e ){
E. printstacktrace ();
Addstr ("an exception occurred while reading the file" + E. tostring ());

} Catch (securityexception e ){
E. printstacktrace ();
Addstr ("permission error occurred during file reading ");

} Finally {
If (is! = NULL ){
Try {
Is. Close ();
} Catch (ioexception e ){
E. printstacktrace ();
}
Is = NULL;
}

If (FC! = NULL ){
Try {
FC. Close ();
} Catch (ioexception e ){
E. printstacktrace ();
}
Fc = NULL;
}
}
}

/**
* Clear information
*
*/
Private void Cls (){
SB. Delete (0, SB. Length ());
Form. deleteall ();
// Form. append (SI );
Form. append (TF );
Form. append (Info );
}

Public void commandaction (command C, displayable arg1 ){
If (C = write) {// write a file
New thread (){
Public void run (){
CLS ();
Write (Tf. getstring (). getbytes ());
}
}. Start ();

} Else if (C = read) {// read the file
New thread (){
Public void run (){
CLS ();
Read ();
}
}. Start ();

} Else if (C = exit) {// exit
Destroyapp (true );
Yydestroyed ();

}

}
}

This article from the csdn blog, reproduced please indicate the source: http://blog.csdn.net/kf156/archive/2009/09/30/4621413.aspx