.

楼主用了个笨方法解决了 就是再加个if判断 count==count++ 就输出负一 不等于就输出count++

求个简单点的方法

contains

//题目要的是下标，不是个数
public class Test {
public static void main(String args[]) {
String s = "123456781234568";
char c = '2';
System.out.println(test1(c, s));
System.out.println(test2(c, s));
System.out.println("count = " + test2(c, s).size());
}
static List<Integer> test1(char c, String s) {
List<Integer> result = new ArrayList<Integer>();
char[] sc = s.toCharArray();
for (int i = 0; i < sc.length; i++) {
if (c == sc[i]) {
result.add(i);
}
}
return result;
}
static List<Integer> test2(char c, String s) {
List<Integer> result = new ArrayList<Integer>();
int index = s.indexOf(c);
while (index != -1) {
result.add(index);
index = s.indexOf(c, index + 1);
}
return result;
}
}

public class Demo01 {
static Scanner sc = new Scanner(System.in);
public static void main(String []args) {
System.out.println("请输入字符串");
String s = sc.next();
System.out.println("请输入字符");
String s1 = sc.next();
fan(s,s1);
}
public static void fan(String s ,String s1) {
boolean b = false;
if (s.contains(s1)){
b=true;
}
if (b) {
char arr [] = s.toCharArray();
char arr1[] = s1.toCharArray();
for (int x = 0;x<arr.length;x++) {
if (arr[x]==arr1[0]) {
System.out.println(x+1);}
}
}else{
System.out.println(-1);
}
}
}