记事本

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package notebook;import java.io.File;import java.util.Hashtable;import java.util.Enumeration;import javax.swing.*;import javax.swing.filechooser.*;public class ExampleFileFilter extends FileFilter {    private static String TYPE_UNKNOWN = "Type Unknown";    private static String HIDDEN_FILE = "Hidden File";    private Hashtable filters = null;    private String description = null;    private String fullDescription = null;    private boolean useExtensionsInDescription = true;      public ExampleFileFilter() {this.filters = new Hashtable();    }    public ExampleFileFilter(String extension) {this(extension,null);    }       public ExampleFileFilter(String extension, String description) {this();if(extension!=null) addExtension(extension); if(description!=null) setDescription(description);    }       public ExampleFileFilter(String[] filters) {this(filters, null);    }        public ExampleFileFilter(String[] filters, String description) {this();for (int i = 0; i < filters.length; i++) {    // add filters one by one    addExtension(filters[i]);} if(description!=null) setDescription(description);    }       public boolean accept(File f) {if(f != null) {    if(f.isDirectory()) {return true;    }    String extension = getExtension(f);    if(extension != null && filters.get(getExtension(f)) != null) {return true;    };}return false;    }         public String getExtension(File f) {if(f != null) {    String filename = f.getName();    int i = filename.lastIndexOf('.');    if(i>0 && i<filename.length()-1) {return filename.substring(i+1).toLowerCase();    };}return null;    }        public void addExtension(String extension) {if(filters == null) {    filters = new Hashtable(5);}filters.put(extension.toLowerCase(), this);fullDescription = null;    }       public String getDescription() {if(fullDescription == null) {    if(description == null || isExtensionListInDescription()) { fullDescription = description==null ? "(" : description + " (";// build the description from the extension listEnumeration extensions = filters.keys();if(extensions != null) {    fullDescription += "." + (String) extensions.nextElement();    while (extensions.hasMoreElements()) {fullDescription += ", " + (String) extensions.nextElement();    }}fullDescription += ")";    } else {fullDescription = description;    }}return fullDescription;    }        public void setDescription(String description) {this.description = description;fullDescription = null;    }      public void setExtensionListInDescription(boolean b) {useExtensionsInDescription = b;fullDescription = null;    }        public boolean isExtensionListInDescription() {return useExtensionsInDescription;    }}

package notebook;import java.awt.*;import java.awt.event.*;import javax.swing.*;import java.io.*;import javax.swing.event.*;import javax.print.*;import javax.print.attribute.*;import java.util.*;import java.text.*;public class MyNotebook extends JFrame implements ActionListener {    Container con;    JScrollPane JSPane;    JTextArea text;    JMenuBar mainMenuBar;    JMenu fileMenu, editMenu, formatMenu, helpMenu;    JMenuItem newItem, openItem, saveItem, saveasItem, pageItem, printItem, exitItem;    JMenuItem undoItem, cutItem, copyItem, pasteItem, findItem, replaceItem, selectallItem, dateItem;    JCheckBoxMenuItem wrapItem;    JMenuItem fontItem;    JMenuItem helpItem, aboutItem;    boolean changed = false;    boolean haveName = false;    File file = null;//主程序入口    public static void main(String[] args) {        MyNotebook notbook = new MyNotebook();        notbook.setVisible(true);    }//创建界面、安装各种监听器、    public MyNotebook() {        setTitle("记事本 -- 未命名");        con = getContentPane();        text = new JTextArea();        JSPane = new JScrollPane(text);        createMenu();        setJMenuBar(mainMenuBar);        con.add(JSPane, BorderLayout.CENTER);        java.awt.Dimension screenSize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();        setBounds((screenSize.width - 800) / 2, (screenSize.height - 600) / 2, 800, 600);    }//创建主菜单    public void createMenu() {        //创建JMenuBar        mainMenuBar = new JMenuBar();        //创建四个JMenu        fileMenu = new JMenu("文件");        editMenu = new JMenu("编辑");        formatMenu = new JMenu("格式");        helpMenu = new JMenu("帮助");        //创建JMenuItem并添加到对应的JMenu中        mainMenuBar.add(fileMenu);        newItem = new JMenuItem("新建");        openItem = new JMenuItem("打开..");        saveItem = new JMenuItem("保存..");        saveasItem = new JMenuItem("另存为..");        pageItem = new JMenuItem("页面设置..");        printItem = new JMenuItem("打印..");        exitItem = new JMenuItem("退出");        fileMenu.add(newItem);        fileMenu.add(openItem);        fileMenu.add(saveItem);        fileMenu.add(saveasItem);        fileMenu.addSeparator();        fileMenu.add(pageItem);        fileMenu.add(printItem);        fileMenu.addSeparator();        fileMenu.add(exitItem);        mainMenuBar.add(helpMenu);        helpItem = new JMenuItem("帮助主题");        aboutItem = new JMenuItem("关于..");        helpMenu.add(helpItem);        helpMenu.add(aboutItem);        exitItem.addActionListener(this);        saveItem.addActionListener(this);        saveasItem.addActionListener(this);        newItem.addActionListener(this);        printItem.addActionListener(this);        openItem.addActionListener(this);    }    public void actionPerformed(ActionEvent e) {        Object obj;        obj = e.getSource();        if (obj == exitItem) {            doExit();        } else if (obj == saveItem) {            doSave();        } else if (obj == saveasItem) {            doSaveAs();        } else if (obj == newItem) {            doNewFile();        } else if (obj == openItem) {            doOpen();        }    }//当用户按下窗口的“关闭”时，会自动调用此方法    protected void processWindowEvent(WindowEvent e) {        if (e.getID() == WindowEvent.WINDOW_CLOSING) {            doExit();        }    }//程序退出时的代码    void doExit() {        int select;        if (!changed) {            System.exit(0);        } else {            select = JOptionPane.showConfirmDialog(this, "文件修改后尚未存盘，要保存吗？");            switch (select) {                case JOptionPane.YES_OPTION:                    select = doSave();                    if (select == 1) {                        System.exit(0);                    }                    break;                case JOptionPane.NO_OPTION:                    System.exit(0);                    break;                case JOptionPane.CANCEL_OPTION:                    break;            }        }    }//保存用户编辑的文件，保存成功返回1，否则返回0    int doSave() {        FileOutputStream fout;        byte content[];        int flag;        if (!haveName) {            flag = doSaveAs();        } else if (changed) {            try {                fout = new FileOutputStream(file);                content = text.getText().getBytes();                fout.write(content);                fout.close();                changed = false;                JOptionPane.showMessageDialog(this, "保存成功！");                flag = 1;            } catch (FileNotFoundException e) {                JOptionPane.showMessageDialog(this, "指定的文件名称或属性有问题！");                flag = 0;            } catch (IOException e) {                JOptionPane.showMessageDialog(this, "无法写文件，请检查文件是否被锁定");                flag = 0;            }        } else {            JOptionPane.showMessageDialog(this, "保存成功，其他情况！");            flag = 1;        }        return flag;    }//用"另存为"对话框保存文件。保存成功返回1，否则返回0    int doSaveAs() {        FileOutputStream fout;        byte content[];        int flag = 0;        File tmpfile = null;        ExampleFileFilter filter = new ExampleFileFilter();        JFileChooser chooser;        filter.addExtension("txt");        filter.setDescription("文本文件");        if (file != null) {            chooser = new JFileChooser(file.getPath());        } else {            chooser = new JFileChooser();        }        chooser.setFileFilter(filter);        flag = chooser.showSaveDialog(this);        if (flag == JFileChooser.APPROVE_OPTION) {            tmpfile = chooser.getSelectedFile();            if (tmpfile.exists()) {                if (JOptionPane.showConfirmDialog(this, "文件已经存在，是否覆盖？",                        "警告", JOptionPane.YES_NO_OPTION) == JOptionPane.YES_OPTION) {                    flag = 1;                } else {                    flag = 0;                }            } else {                flag = 1;            }        } else {            flag = 0;        }        if (flag == 1) {//用户已经确定要以指定名称保存文件            try {                fout = new FileOutputStream(tmpfile);                content = text.getText().getBytes();                fout.write(content);                fout.close();                flag = 1;            } catch (FileNotFoundException e) {                JOptionPane.showMessageDialog(this, "指定的文件名称或属性有问题！");                flag = 0;            } catch (IOException e) {                JOptionPane.showMessageDialog(this, "无法写文件，请检查文件是否被锁定");                flag = 0;            }        }        if (flag == 1) {//文件保存成功，修改相关变量            changed = false;            haveName = true;            file = tmpfile;            this.setTitle(file.getName() + " - 记事本");        }        return flag;    }//新建一个文件    void doNewFile() {        int select, flag;        if (changed) {            select = JOptionPane.showConfirmDialog(this, "文件修改后尚未存盘，要保存吗？");            switch (select) {                case JOptionPane.YES_OPTION:                    flag = doSave();                    break;                case JOptionPane.NO_OPTION:                    flag = 1;                    break;                default:                    flag = 0;                    break;            }        } else {            flag = 1;        }        if (flag == 1) {            changed = false;            haveName = false;            setTitle("记事本 -- 未命名");            text.setText(null);        }    }//打开一个已经存在的文件    void doOpen() {        int select, flag;        File tmpfile = null;        ExampleFileFilter filter;        JFileChooser chooser;        FileInputStream fin;        byte buf[];        if (changed) {            select = JOptionPane.showConfirmDialog(this, "文件修改后尚未存盘，要保存吗？");            switch (select) {                case JOptionPane.YES_OPTION:                    flag = doSave();                    break;                case JOptionPane.NO_OPTION:                    flag = 1;                    break;                default:                    flag = 0;                    break;            }        } else {            flag = 1;        }        if (flag == 1) {            changed = false;            filter = new ExampleFileFilter();            filter.addExtension("txt");            filter.setDescription("文本文件");            if (file != null) {                chooser = new JFileChooser(file.getPath());            } else {                chooser = new JFileChooser();            }            chooser.setFileFilter(filter);            select = chooser.showOpenDialog(this);            if (select == JFileChooser.APPROVE_OPTION) {                tmpfile = chooser.getSelectedFile();                try {                    fin = new FileInputStream(tmpfile);                    buf = new byte[(int) tmpfile.length()];                    fin.read(buf);                    fin.close();                    text.setText(new String(buf));                    changed = false;                    haveName = true;                    file = tmpfile;                    setTitle("记事本 -- " + file.getName());                } catch (FileNotFoundException e) {                    JOptionPane.showMessageDialog(this, "指定的文件名称或属性有问题！");                } catch (IOException e) {                    JOptionPane.showMessageDialog(this, "无法读文件，请检查文件是否被锁定");                }            }        }    }}

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