24-2.Java中的Character:char类型的包装类类型(二)

主要了一些功能

(1) public static boolean isUpperCase(char ch):判断当前字符是否大写字母字符

(2) public static boolean isLowerCAse(char ch):是否为小写字母字符  

(3)public static boolean isDigit(char ch):是否为数字字符

String转换的功能很类似

(1)public static char toLowerCase(char ch):将字符转换成小写

(2)public static char toUpperCase(char ch):将字符转换成大写

​
public class CharacterDemo {
    public static void main(String[] args) {

        //创建字符类对象
        Character character = new Character('a') ;
//        Character character = new Character((char)(97)) ;
        System.out.println(character);

        System.out.println("---------------------------------");

        System.out.println("isUpperCase():"+Character.isUpperCase('A'));
        System.out.println("isUpperCase():"+Character.isUpperCase('a'));
        System.out.println("isUpperCase():"+Character.isUpperCase('0'));

        System.out.println("---------------------------------");

        System.out.println("isLowerCase():"+Character.isLowerCase('A'));
        System.out.println("isLowerCase():"+Character.isLowerCase('a'));
        System.out.println("isLowerCase():"+Character.isLowerCase('0'));

        System.out.println("---------------------------------");

        System.out.println("isDigit():"+Character.isDigit('A'));
        System.out.println("isDigit():"+Character.isDigit('a'));
        System.out.println("isDigit():"+Character.isDigit('0'));

      
    }
}

​

 1.键盘录入一个字符串,有大写字母字符,数字字母字符,小写字母字符,不考虑其他字符,分别统计

 大写字母字符,小写字母字符,数字字符的个数

public class Test {
    public static void main(String[] args) {

        //定义三个统计变量
        int bigCount = 0  ;
        int smallCount = 0 ;
        int numberCount =  0;
        //创建键盘录入对象
        Scanner sc = new Scanner(System.in) ;

        //提示并录入数据
        System.out.println("请您输入一个数据:");
        String line = sc.nextLine() ;

        //转换成字符数组
        char[] chs = line.toCharArray();
        for (int i = 0; i <chs.length ; i++) {
            char ch = chs[i] ;
            if(Character.isDigit(ch)){
                numberCount ++ ;
            }else if(Character.isUpperCase(ch)){
                bigCount ++ ;
            }else if(Character.isLowerCase(ch)){
                smallCount ++;
            }

        }

        System.out.println("大写字母字符有"+bigCount+"个");
        System.out.println("小写字母字符有"+smallCount+"个");
        System.out.println("数字字符有"+numberCount+"个");
    }
}