java读取txt字符串挨个写入int数组

 int []num=new int[1001];
   FileReader fr = new FileReader("1.txt");
   BufferedReader br = new BufferedReader(fr);

 String str;
   StringBuilder sb = new StringBuilder();
   while((str=br.readLine())!=null)
   {
    sb.append(str);
   }
   String st=sb.toString();
    int sum=0,mynum;
    for(int i=0;i<st.length();i++)
    {
     num[i]=Integer.parseInt(st.substring(i,i+1));
    }

乍看 很麻烦！