为什么运行时显示找不到文件，而且程序并没有因异常而终止

public void exportPlayList() {

try {

File file=new File(this.getPlayListName()+"的歌单.txt");

file.createNewFile();

FileInputStream fis;

BufferedInputStream bis;

InputStreamReader isr;

FileOutputStream fos;

BufferedOutputStream bos;

OutputStreamWriter osw;

for(int i=0;i<this.getMusicList().size();i++) {

String str=((Song)(this.getMusicList().get(i))).toString();

   fis=new FileInputStream(str);    

   bis=new BufferedInputStream(fis);

   isr=new InputStreamReader(bis);

   fos=new FileOutputStream(file);

bos=new BufferedOutputStream(fos);

osw=new OutputStreamWriter(bos);

   int n=0;

   char[] cha=new char[100];

   while((n=isr.read(cha))!=-1){

    String s=new String(cha,0,n);

    osw.write(s);

    osw.flush();

   }    

fis.close();

bis.close();

isr.close();

fos.close();

bos.close();

osw.close();

}

}catch (FileNotFoundException e1) {

e1.printStackTrace();

}catch (IOException e) {

e.printStackTrace();

}