How to implement text editor in Java language

Introduction

A simple text compiler that can open files through pop-up dialog boxes, write and save files.

Code

package Code.a;
import java.io.*;
import javax.swing.*;
import java.awt.event.*;
public class Editor implements ActionListener{
    JFrame f;
    JTextArea ta;
    JScrollPane sp;
    JMenuBar menubar;
    JMenu menu;
    JMenuItem openItem,saveItem,closeItem,exitItem;
    FileReader fr;
    FileWriter fw;
    JFileChooser fc;
    File file;
    //构造界面，本类作为监听类；
    public Editor(){
        f = new JFrame("简易文本编辑器");
        ta = new JTextArea();
        sp = new JScrollPane(ta);//滚轮
        f.add(sp);
        
        menubar = new JMenuBar();//菜单栏
        menu = new JMenu("File"); 
        openItem = new JMenuItem("Open");//四个选项
        saveItem = new JMenuItem("Save");
        closeItem = new JMenuItem("Close");
        exitItem = new JMenuItem("Exit");
        menu.add(openItem);
        menu.add(saveItem);
        menu.add(closeItem);
        menu.add(exitItem);
        menubar.add(menu);
        
        f.setJMenuBar(menubar);
        f.setSize(400,300);
        f.setVisible(true);
        //四个选项事件函数；
        openItem.addActionListener(this);
        saveItem.addActionListener(this);
        closeItem.addActionListener(this);
        exitItem.addActionListener(this);
    }
    public void actionPerformed(ActionEvent e)
    {
        //异常
        try {
            //点击打开选项时，弹出打开文件对话框；
            if(e.getActionCommand()=="Open") {
                fc = new JFileChooser();
                if(fc.showOpenDialog(null) == JFileChooser.APPROVE_OPTION)
                {
                    file = fc.getSelectedFile();
                    fr = new FileReader(file);
                    int c;
                    while((c = fr.read()) != -1)
                    {
                        ta.append(String.valueOf((char) c));
                    }
                    fr.close();
                }
            }
            //点击保存选项时，弹出保存文件对话框；
            else if(e.getActionCommand()=="Save") {
                
                String str = ta.getText();
                fc = new JFileChooser();
                if(fc.showSaveDialog(null) == JFileChooser.APPROVE_OPTION)
                {
                    file = fc.getSelectedFile();
                    fw = new FileWriter(file);
                    fw.write(str);
                    fw.close();
                }
            }
            //点击关闭选项时，清空文本框；
            else if(e.getActionCommand() == "Close") {
                ta.setText("");
            }
            //点击退出选项时，退出当前界面；
            else if(e.getActionCommand() == "Exit") {
                System.exit(0);
            }
        }
        //处理异常；
        catch(IOException exp) {
            exp.printStackTrace();
        }
    }
    public static void main(String[] args) {
        Editor e = new Editor();

    }

}

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