1 /**
2 * 首字母变大写
3 *
4 * @param str 字符串
5 * @return {String}
6 */
7 public static String firstCharToUpper(String str) {
8 char firstChar = str.charAt(0);
9 if (firstChar >= 'a' && firstChar <= 'z') {
10 char[] arr = str.toCharArray();
11 arr[0] -= ('a' - 'A');
12 return new String(arr);
13 }
14 return str;
15 }
1 /**
2 * 首字母变小写
3 *
4 * @param str 字符串
5 * @return {String}
6 */
7 public static String firstCharToLower(String str) {
8 char firstChar = str.charAt(0);
9 if (firstChar >= 'A' && firstChar <= 'Z') {
10 char[] arr = str.toCharArray();
11 arr[0] += ('a' - 'A');
12 return new String(arr);
13 }
14 return str;
15 }
