public class Solution { public static void main(String args[]) { testSolutions.lowercaseToUppercase('A'); testSolutions.UppercaseTolowercase('a'); } } class Solutions { /** * @param character: a character * @return: a character */ public char lowercaseToUppercase(char character) { // 转大写 String UppercaseCharacter = String.valueOf(character).toUpperCase(); System.out.println(UppercaseCharacter.charAt(0)); return UppercaseCharacter.charAt(0); } public char UppercaseTolowercase(char character) { // 转小写 String lowercaseCharacter = String.valueOf(character).toLowerCase(); System.out.println(lowercaseCharacter.charAt(0)); return lowercaseCharacter.charAt(0); } }