JAVA实现字母加密

/**
 * <p>Filename: Calculation.java</p>
 * <p>Copyright:Copyright(c)2009</p>
 * @author 楚雄好地方
 * @version 200907
 *  */
//实现将键盘输入的字母加密。例如：A变成Z，B变成Y以此类推
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class shixun1_1 {
    public static void main(String[] args) {
        String outputStr = "";
                     System.out.print("请输入字母：");
        //从键盘输入字母
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        try {
            //读取行，赋值给inputStr
            String inputStr = br.readLine();           
            for(int i=0;i<inputStr.length();i++){
                //将转换后的字符连接成字符串输出
                outputStr = outputStr + changeLetter(inputStr.charAt(i));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
       
        System.out.println(outputStr);
    }
    public static char changeLetter(char c){
        //用于后台打印，知道Unicode码
        /*Integer num1 = 'A';
        Integer num2 = 'Z';
        Integer num3 = 'a';
        Integer num4 = 'z';       
        System.out.println(num1);
        System.out.println(num2);
        System.out.println(num3);
        System.out.println(num4);*/
        //unicode码
        //A值为65
        //Z值为90
        //a值为97
        //b值为122       
       
        int letter = c;       
        char character = 0;
        if(c>=65&&c<=90){
            //比如输入B，则运算步骤如下：
            //90-（66-65）=89，89转换成字符则为Y
            //以下小写的同理
            character = (char)(90-(letter-65));
        }
        if(c>=97&&c<=122){
            character = (char)(122-(letter-97));
        }       
        return character;
    }
}