Java代码案例47——利用字符编码进行字符串加密和解密

源文件

package xiangmu;
public class Ceshi {
    public static void main(String args[]) {
        // 利用ASCII码表对字符串进行加密和解密
        String zifuchuan = "I'm 20 years old.";
        // 密钥是正整数，假定为3，这个是加密和解密的钥匙
        // 修改密钥可以得到不同的加密后的字符串
        int miyao = 3;
        System.out.println("原始字符串为：" + zifuchuan);
        String jiamihou = jiami(zifuchuan, miyao);
        System.out.println("加密后的字符串为：" + jiamihou);
        String jiemihou = jiemi(jiamihou, miyao);
        System.out.println("解密后的字符串为：" + jiemihou);
    }
    public static String jiami(String zfc, int my) {
        // zfc 要加密的字符串
        // my 约定好的密钥
        String xinzfc = "";
        for(int i = 0; i < zfc.length(); i = i + 1) {
            xinzfc = xinzfc + (char)(zfc.charAt(i) + my);
        }
        return xinzfc;
    }
    public static String jiemi(String zfc, int my) {
        // zfc 要解密的字符串
        // my 约定好的密钥
        String xinzfc = "";
        for(int i = 0; i < zfc.length(); i = i + 1) {
            xinzfc = xinzfc + (char)(zfc.charAt(i) - my);
        }
        return xinzfc;
    }
} 
原始字符串为：I'm 20 years old.
加密后的字符串为：L*p#53#|hduv#rog1
解密后的字符串为：I'm 20 years old.