public static void main(String []args){
int ch=0;
int nu=0;
int blank=0;
int ot=0;
String st = JOptionPane.showInputDialog("请输入字符串");
for(int i=0;i<st.length();i++){
char n=st.charAt(i);
if(n>='0'&&n<='9')nu++;
else if((n>='a'&n<='z')||(n>='A'&n<='Z'))ch++;
else if(n==' ')blank++;
else ot++;
}
System.out.println("数字:"+nu);
System.out.println("字母:"+ch);
System.out.println("空格:"+blank);
System.out.println("其他:"+ot);
}
追问我想再问一句、您能否用正则表达式帮我写一个?