public class base_day01 { public static void main(String[] arg) { String str = "統計字符串中的某個字在字符串中出現的位置"; int[] iArr = countAll(str,'字'); System.out.println(Arrays.toString(iArr)); } private static int[] countAll(String str,char ch) { int[] iArr={}; for(int i = 0; i < str.length();i++){ char c =str.charAt(i); if (c==ch){ iArr = Arrays.copyOf(iArr,iArr.length+1);//數組複製,新建的內存 iArr[iArr.length-1] = i; } } return iArr; } }結果: [2, 9, 11]