java三种判断字母大小写的方法

 public class AaNum {

public static void main(String[] args)

{

String s = new String("12HMa&%$k#d_34H3aH");

int max = 0;

int min = 0;

int other = 0;

for (int i = 0;i < s.length();i++)

{

if(s.charAt(i)>='A'&&s.charAt(i)<='Z')

{

max++;

}

else if(s.charAt(i)>='a'&&s.charAt(i)<='z')

{

min++;

}

else

other++;

}

System.out.println("max:"+max+"\nmin:"+min+"\nother:"+other);

max = 0;

min = 0;

other = 0;

for (int i = 0;i < s.length();i++)

{

if(Character.isUpperCase(s.charAt(i)) == true)

{

max++;

}

else if(Character.isLowerCase(s.charAt(i)) == true)

{

min++;

}

else

other++;

}

System.out.println("max:"+max+"\nmin:"+min+"\nother:"+other);

max = 0;

min = 0;

other = 0;

String sL = "abcdefghijklmnopqrstuvwxyz";

String sU = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

for (int i = 0;i < s.length();i++)

{

if(sL.indexOf(s.charAt(i)) != -1)

{

max++;

}

else if(sU.indexOf(s.charAt(i)) != -1)

{

min++;

}

else

other++;

}

System.out.println("max:"+max+"\nmin:"+min+"\nother:"+other);

}

}