java读取txt字符串挨个写入int数组

 1 int []num=new int[1001];
 2   FileReader fr = new FileReader("1.txt");
 3   BufferedReader br = new BufferedReader(fr);
 4 
 5 String str;
 6   StringBuilder sb = new StringBuilder();
 7   while((str=br.readLine())!=null)
 8   {
 9    sb.append(str);
10   }
11   String st=sb.toString();
12    int sum=0,mynum;
13    for(int i=0;i<st.length();i++)
14    {
15     num[i]=Integer.parseInt(st.substring(i,i+1));
16    }

乍看 很麻烦！