Java中大小写转换

public class Test {

public Test(){}

public static void main(String[] args) {
String str = "aaFF";
StringBuffer sb = new StringBuffer();
char[] charArray = str.toCharArray();
char temp;
for (int i = 0; i < charArray.length; i++) {
if (charArray[i] >= 'a' && charArray[i] <= 'z') {
temp = (char) (charArray[i] - 32);
sb.append(temp);
}
if (charArray[i] >= 'A' && charArray[i] <= 'Z') {
temp = (char) (charArray[i] + 32);
sb.append(temp);
}
}
System.out.println(str + "大小写转换后是：" + sb);
}


}


}