public class TestStr {

public static void main(String[] args) {

Scanner scan = new Scanner(System.in);

System.out.println("请输入字符串:");

String str = scan.next();

System.out.println("输入次数:");

int times = scan.nextInt();

char chr = getChar(str, times);

if(chr != ' ') {

System.out.println(chr);

}else {

System.out.println("未找到满足要求的值");

}

}

public static char getChar(String str, int times) {

for (int i = 0; i < str.length(); i++) {

String param = "[^(" + str.charAt(i) +")]";   //正则表达式

String s = str.replaceAll(param, "").trim();  //把不满足正则表达式的替换成空字符

if(s.length() >= times) {       //判断匹配后的字符长度是否满足

return str.charAt(i);

}

}

return ' ';

}

}