//加密字符串
import javax.swing.JOptionPane;
public class Jami {
public static void main(String[] args)
{
String
s1 = JOptionPane.showInputDialog("请输入字符串:");
String output;
output = "字符串:"+s1;
char[] c = new char[s1.length()];
s1.getChars(0, s1.length(), c,0);
//加密
for(int i=0;i<s1.length();i++)
{
if(c[i]=='X')
c[i]='A';
else if(c[i]=='Y')
c[i]='B';
else if(c[i]=='Z')
c[i]='C';
else if (c[i] == ' ')
c[i]=c[i];
else
c[i]+=3;
}
output=new String(c);
//解密
char[] S2 = new char[s1.length()];
s1.getChars(0, s1.length(), S2,0);
for(int i=0;i<s1.length();i++)
{
if(S2[i]=='C')
S2[i]='Z';
else if(S2[i]=='B')
S2[i]='Y';
else if(S2[i]=='A')
S2[i]='X';
else if(S2[i] == ' ')
S2[i]=S2[i];
else
S2[i]-=3;
}
String o=new String(S2);
output +="\n\n解密后的字符串是:"+o;//定义输出格式
JOptionPane.showMessageDialog(
null,"加密后的字符串是:"+output,"字符串"+s1,
JOptionPane.PLAIN_MESSAGE);
System.exit(0);
}
}
![](https://images2015.cnblogs.com/blog/811593/201510/811593-20151024174917020-76624623.png)