加密字符串

//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 +="

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);
        
    }

	}