Question

我正在创建一个java程序，当你在textarea上输入内容时，另一个textarea会自动加密字符。我正在使用Caesar的密码。

示例：我在第一个textarea上键入QWERTY。当我输入Q时，第二个文本区域自动显示结果N，然后是W，它将显示T等等。

到目前为止，这是我的代码。它看起来像一个记事本。保存文件时，它将自动转换为Caesar的密码。我想改变它的外观，以便用户可以在他/她打字时看到该消息的样子。

import javax.swing.*;
import java.awt.*;
import java.io.*;
import java.util.*;
import java.awt.event.*;

public class LeftShift implements ActionListener
{
    public static LeftShift f = new LeftShift();

    Container content;

JFrame frame;
JTextArea txtarea = new JTextArea("");
JScrollPane scroll = new JScrollPane();
JPanel panel = new JPanel();
JMenuBar mb = new JMenuBar();
JMenu file= new JMenu("File");
JMenu about= new JMenu("About");
JMenuItem new1 = new JMenuItem("New");
JMenuItem open = new JMenuItem("Open");
JMenuItem save= new JMenuItem("Save");
JMenuItem saveas= new JMenuItem("Save As");
JMenuItem exit= new JMenuItem("Exit");
JMenuItem author= new JMenuItem("Author");

File fileopened = null;

public void mainFrame()
{
    frame = new JFrame("Untitled - Notepad");
    content = frame.getContentPane();

    frame.setSize(500,500);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    scroll = new JScrollPane(txtarea);
    frame.add(scroll);
    frame.setJMenuBar(mb);
    mb.add(file);
    mb.add(about);
    file.add(new1);
    file.add(open);
    file.add(save);
    file.add(saveas);
    file.add(exit);
    about.add(author);

    new1.addActionListener(this);
    open.addActionListener(this);
    save.addActionListener(this);
    saveas.addActionListener(this);
    exit.addActionListener(this);
    author.addActionListener(this);

}

public static void main(String args[])
{
    f.mainFrame();
}

public void actionPerformed(ActionEvent e)
{
    if(e.getSource()==new1)
    {
        txtarea.setText("");
        frame.setTitle("Untitled - Notepad");
        fileopened = null;
    }
    else if(e.getSource()==open)
    {
        JFileChooser chooser = new JFileChooser();  

        int returnvalue = chooser.showOpenDialog(null);
        if(returnvalue==chooser.APPROVE_OPTION)
        {
            fileopened = chooser.getSelectedFile();
            frame.setTitle(fileopened.getName() + " - Notepad");

            String s = new String("");
            String str = new String("");

            try
            {
                Scanner scanner = new Scanner(fileopened);

                while(scanner.hasNext())
                {
                        s = scanner.nextLine();
                        str += Decrypt(s) + "\n";   
                }   

                txtarea.setText(str);
            }

            catch(FileNotFoundException fnfe)
            {}
        }           
    }
    else if(e.getSource()==save)
    {
        if(fileopened != null)
        {

                String s = new String("");

                try
                {
                    BufferedWriter bw = new BufferedWriter(new FileWriter(fileopened,false));

                    Scanner scanner = new Scanner(txtarea.getText());

                    while(scanner.hasNext())
                    {
                        s = scanner.nextLine();
                        bw.write(Encrypt(s));
                        bw.newLine();   
                    }

                    bw.close();
                    frame.setTitle(fileopened.getName() + " - Notepad");
                }
                catch(IOException ioe)
                {}  
        }
        else
        {
            JFileChooser chooser = new JFileChooser();  

            int returnvalue = chooser.showSaveDialog(null);
            if(returnvalue==chooser.APPROVE_OPTION)
            {
                fileopened = chooser.getSelectedFile();

                String s = new String("");

                try
                {
                    BufferedWriter bw = new BufferedWriter(new FileWriter(fileopened,false));

                    Scanner scanner = new Scanner(txtarea.getText());

                    while(scanner.hasNext())
                    {
                        s = scanner.nextLine();
                        bw.write(Encrypt(s));
                        bw.newLine();   
                    }

                    bw.close();
                    frame.setTitle(fileopened.getName() + " - Notepad");
                }
                catch(IOException ioe)
                {}
            }
        }
    }
    else if(e.getSource()==saveas)
    {
        JFileChooser chooser = new JFileChooser();  

        int returnvalue = chooser.showOpenDialog(null);
        if(returnvalue==chooser.APPROVE_OPTION)
        {
            fileopened = chooser.getSelectedFile();

            String s = new String("");

            try
            {
                BufferedWriter bw = new BufferedWriter(new FileWriter(fileopened,false));

                Scanner scanner = new Scanner(txtarea.getText());

                while(scanner.hasNext())
                {
                        s = scanner.nextLine();
                        bw.write(Encrypt(s));
                        bw.newLine();   
                }

                bw.close();
                frame.setTitle(fileopened.getName() + " - Notepad");
            }
            catch(IOException ioe)
            {

            }
        }
    }
    else if(e.getSource()==exit)
    {
        System.exit(0);
    }
    else if(e.getSource()==author)
    {
        JOptionPane.showMessageDialog(null,"Caesar Encipher and Decipher LeftShift");
    }

}

public String Encrypt(String s)
{
    String str = new String();
    for ( int i = 0; i < s.length(); ++i )
    {
        char c = s.charAt(i);
        int j = (int) c;

        if(j>=65 && j<=67) //Letter ABC
        {   
            switch(j)
            {
                case 65:
                    j=88;
                    break;
                case 66:
                    j=89;
                    break;
                case 67:
                    j=90;
                    break;
            }
        }
        else if(j>=97 && j<=99) //Letter abc
        {
            switch(j)
            {
                case 97:
                    j=120;
                    break;
                case 98:
                    j=121;
                    break;
                case 99:
                    j=122;
                    break;
            }           
        }
        else if(j>=68 && j<=90) //Letter D-Z
        {
            j-=3;
        }
        else if(j>=100 && j<=122) //Letter d-z
        {
            j-=3;
        }

        c = (char) j;
        str += c;
    }
    return str;
}

public String Decrypt(String s)
{
    String str = new String();
    for ( int i = 0; i < s.length(); ++i )
    {
        char c = s.charAt(i);
        int j = (int) c;

        if(j>=88 && j<=90) //Letter XYZ
        {   
            switch(j)
            {
                case 88:
                    j=65;
                    break;
                case 89:
                    j=66;
                    break;
                case 90:
                    j=67;
                    break;
            }
        }
        else if(j>=120 && j<=122) //Letter xyz
        {
            switch(j)
            {
                case 120:
                    j=97;
                    break;
                case 121:
                    j=98;
                    break;
                case 122:
                    j=99;
                    break;
            }           
        }
        else if(j>=65 && j<=87) //Letter A-W
        {
            j+=3;
        }
        else if(j>=97 && j<=119) //Letter a-w
        {
            j+=3;
        }

        c = (char) j;
        str += c;
    }
    return str;
}
    }

Answer 1

将DocumentListener添加到第一个文本区域。当事件触发时，您可以翻译并更新第二个文本区域。

有关详细信息，请参阅How to Write a DocumentListener。

不要忘记处理文本区域中的文本删除。

键入时转换字符串

1 个答案: