try
{
fr = new FileReader( args[ 0 ] );
}
catch ( FileNotFoundException e )
{
System.out.println( "Source File not found" );
return;
}

try
{
fw = new FileWriter( args[ 1 ] );
}
catch ( IOException e )
{
System.out.println( "Target File write error" );
return;
}


fw失败时，不用释放fr？