Question

用java编写一个数据加密的程序

要求：（1）输入任意一串明文M。
（2）根据以下公式将其转换为密文C。
j=i+k mod 26 其中，j，i 为字母在26个字母表中的第j、i位;
k为输入参数 k=1,2,…..,10
（3）具有输入输出界面。

Answer 1

import java.util.HashMap;
import java.util.Map;

public class NewJFrame extends javax.swing.JFrame {
public static Map<Character,Integer> charmap = new HashMap<Character,Integer>();
public static char stringmap[] = new char[]{'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o',
'p','q' ,'r','s','t','u','v','w','x','y','z'
};
static{
charmap.put('a', 1);
charmap.put('b', 2);
charmap.put('c', 3);
charmap.put('d', 4);
charmap.put('e', 5);
charmap.put('f', 6);
charmap.put('g', 7);
charmap.put('h', 8);
charmap.put('i', 9);
charmap.put('j', 10);
charmap.put('k', 11);
charmap.put('l', 12);
charmap.put('m', 13);
charmap.put('n', 14);
charmap.put('o', 15);
charmap.put('p', 16);
charmap.put('q', 17);
charmap.put('r', 18);
charmap.put('s', 19);
charmap.put('t', 20);
charmap.put('u', 21);
charmap.put('v', 22);
charmap.put('w', 23);
charmap.put('x', 24);
charmap.put('y', 25);
charmap.put('z', 26);

charmap.put('A', 1);
charmap.put('B', 2);
charmap.put('C', 3);
charmap.put('D', 4);
charmap.put('E', 5);
charmap.put('F', 6);
charmap.put('G', 7);
charmap.put('H', 8);
charmap.put('I', 9);
charmap.put('J', 10);
charmap.put('K', 11);
charmap.put('L', 12);
charmap.put('M', 13);
charmap.put('N', 14);
charmap.put('O', 15);
charmap.put('P', 16);
charmap.put('Q', 17);
charmap.put('R', 18);
charmap.put('S', 19);
charmap.put('T', 20);
charmap.put('U', 21);
charmap.put('V', 22);
charmap.put('W', 23);
charmap.put('X', 24);
charmap.put('Y', 25);
charmap.put('Z', 26);
}
public NewJFrame() {
initComponents();
}

private char change(char c) {
int i = charmap.get(c);
int k = 2;
int j;
j=(i+k) % 26 ;
return stringmap[--j];
}

// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

jPanel1 = new javax.swing.JPanel();
ba = new javax.swing.JButton();
ta = new javax.swing.JTextField();
tb = new javax.swing.JTextField();

setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

ba.setText("转换");
ba.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
baActionPerformed(evt);
}
});

tb.setEnabled(false);

javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(66, 66, 66)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(tb)
.addComponent(ta, javax.swing.GroupLayout.DEFAULT_SIZE, 316, Short.MAX_VALUE)))
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(147, 147, 147)
.addComponent(ba, javax.swing.GroupLayout.PREFERRED_SIZE, 79, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addContainerGap(59, Short.MAX_VALUE))
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addComponent(ta, javax.swing.GroupLayout.PREFERRED_SIZE, 38, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(tb, javax.swing.GroupLayout.DEFAULT_SIZE, 38, Short.MAX_VALUE)
.addGap(18, 18, 18)
.addComponent(ba)
.addContainerGap())
);

javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);

pack();
}// </editor-fold>

private void baActionPerformed(java.awt.event.ActionEvent evt) {
String aa = ta.getText();
char bb[] = aa.toCharArray();
char cc[] = new char[bb.length];
for(int i = 0; i < bb.length;i++){
cc[i] = change(bb[i]);
}
tb.setText(String.valueOf(cc));
}

public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new NewJFrame().setVisible(true);
}
});
}

// Variables declaration - do not modify
private javax.swing.JButton ba;
private javax.swing.JPanel jPanel1;
private javax.swing.JTextField ta;
private javax.swing.JTextField tb;
// End of variables declaration

}

private void initComponents() 这个方法不用太在意，只是个生成界面的方法而已......
看不懂这个方法也没关系

Answer 2

void recode(int[] M , int k) {
for(int j = 0 ; j < M.length ; j++){
M[j] = (M[j] + k) % 26 ;
}
}