Android中字符串操作简介

字符串排序（冒泡排序）

public static String strSort(String str){
  char[] chars = str.toCharArray();
  for (int i = 0; i < chars.length - 1; i++) {
    for (int j = i + 1; j < chars.length; j++) {
      if(chars[i] < chars[j]){
        char temp = chars[i];
        chars[i] = chars[j];
        chars[j] = temp;
      }
    }
  }
  return new String(chars);
}

字符串比较大小

public static int strSort(String str1, String str2) {
  char[] chars1 = str1.toCharArray();
  char[] chars2 = str2.toCharArray();
  int size = chars1.length < chars2.length ? chars1.length : chars2.length;
  for (int i = 0; i < size; i++) {
    if (intCompare(chars1[i], chars2[i]) != 0)
      return intCompare(chars1[i], chars2[i]);
  }
  return intCompare(chars1.length, chars2.length);
}

private static int intCompare(char char1, char char2) {
  if (char1 > char2) {
    return 1;
  } else if (char1 < char2) {
    return -1;
  } else {
    return 0;
  }
}

private static int intCompare(int char1, int char2) {
  if (char1 < char2) {
    return -1;
  } else if (char1 > char2) {
    return 1;
  } else {
    return 0;
  }
}

反转字符串

public static String reverseString(String str) {
  if (str == null || str.length() < 2)
    return str;
  return reverseString(str.substring(1, str.length())) + str.charAt(0);
}

获取某段字符

public static String cutOutString(String str) {
  return str.substring(str.indexOf("ah"), str.indexOf("bd"));
}

判断字符串中出现的子字符串的次数

public static int countStr(String str, String key) {
  int total = 0;
  for (String tmp = str; tmp != null && tmp.length() >= key.length(); ) {
    if (tmp.indexOf(key) == 0)
        total++;
      tmp = tmp.substring(1);
  }
    return total;
}