大学收费系统- Java

Question

我开发了一个使用Java和internet作为参考的大学费用报告生成器应用程序，但是现在我需要你们的帮助，使它变得更加明显和坚固，因为我是Java Swing的新手。

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.FileWriter;


public class College extends Frame {

    JLabel l1, l2, l3, l4,
            l5, l6, l7, l8,
            l9, l10, l12, l13,
            l14, l11, l15;

    JTextField tf1, tf2, tf3,
            tf4, tf5, tf6,
            tf7, tf8, tf9,
            tf10;

    JTextArea area2, area1;

    JRadioButton rb1, rb2, rb3,
            rb4, rb5, rb6,
            rb7;

    JFileChooser f1;

    // Default constructor to
    // initialize the parameters
    College()
    {


        l1 = new JLabel("Fee Report");
        l1.setBounds(550, 100, 250, 20);

        l2 = new JLabel(
                "Name of the Student:");
        l2.setBounds(50, 150, 250, 20);

        tf1 = new JTextField();
        tf1.setBounds(250, 150, 250, 20);

        l3 = new JLabel(
                "Name of the Father:");
        l3.setBounds(50, 200, 250, 20);

        tf2 = new JTextField();
        tf2.setBounds(250, 200, 250, 20);

        l4 = new JLabel("Roll Number:");
        l4.setBounds(50, 250, 250, 20);

        tf3 = new JTextField();
        tf3.setBounds(250, 250, 250, 20);

        l5 = new JLabel("Email ID:");
        l5.setBounds(50, 300, 250, 20);

        tf4 = new JTextField();
        tf4.setBounds(250, 300, 250, 20);

        l6 = new JLabel("Contact Number:");
        l6.setBounds(50, 350, 250, 20);

        tf5 = new JTextField();
        tf5.setBounds(250, 350, 250, 20);

        l7 = new JLabel("Address:");
        l7.setBounds(50, 400, 250, 20);

        area1 = new JTextArea();
        area1.setBounds(250, 400, 250, 90);

        l9 = new JLabel("Gender:");
        l9.setBounds(50, 500, 250, 20);

        JRadioButton r5
                = new JRadioButton(" Male");
        JRadioButton r6
                = new JRadioButton(" Female");

        r5.setBounds(250, 500, 100, 30);
        r6.setBounds(350, 500, 100, 30);

        ButtonGroup bg = new ButtonGroup();
        bg.add(r5);
        bg.add(r6);

        l10 = new JLabel("Nationality:");
        l10.setBounds(50, 550, 250, 20);

        String nationality[]
                = { "Indian","Other"};

        final JComboBox cb3
                = new JComboBox(nationality);

        cb3.setBounds(250, 550, 250, 20);

        l11 = new JLabel(
                "Year of passing 10th");
        l11.setBounds(50, 600, 250, 20);

        String language[]
                = { "2017","2016", "2015", "2014" ,"2013","2012"};

        final JComboBox cb1
                = new JComboBox(language);

        cb1.setBounds(250, 600, 90, 20);

        l12 = new JLabel(
                "Year of passing 12th");
        l12.setBounds(50, 650, 250, 20);

        String languagess[]
                = { "2020","2019", "2018", "2017","2016","2015" };


        l13 = new JLabel(
                "Percentage Secured in 10th:");
        l13.setBounds(50, 700, 250, 20);

        tf7 = new JTextField();
        tf7.setBounds(250, 700, 250, 20);

        l14 = new JLabel("Percentage Secured in 12th:");
        l14.setBounds(50, 750, 250, 20);

        tf8 = new JTextField();
        tf8.setBounds(250, 750, 250, 20);

        ImageIcon i2 = new ImageIcon("2.png");
        JLabel l15
                = new JLabel("", i2, JLabel.CENTER);

        l15.setBounds(900, 50, 600, 200);

        final JComboBox cb2
                = new JComboBox(languagess);

        cb2.setBounds(250, 650, 90, 20);
        l8 = new JLabel(
                "Groups Offered here are:");
        l8.setBounds(800, 150, 250, 20);

        rb1 = new JRadioButton("Engineering");
        rb1.setBounds(550, 150, 100, 30);

        rb2 = new JRadioButton("Arts");
        rb2.setBounds(650, 150, 100, 30);

        ButtonGroup bg1 = new ButtonGroup();

        bg1.add(rb1);
        bg1.add(rb2);

        rb3 = new JRadioButton("Hosteller / Residential ");
        rb3.setBounds(550, 200, 100, 30);

        rb4 = new JRadioButton("Day-Scholar");
        rb4.setBounds(650, 200, 120, 30);

        ButtonGroup bg2 = new ButtonGroup();
        bg2.add(rb3);
        bg2.add(rb4);

        String languages[]
                = { "CSE", "ECE", "EEE","IT","AERO","MCT","AUTO","PROD","TEXT","CIVIL", "MECH" };
        final JComboBox cb
                = new JComboBox(languages);
        cb.setBounds(800, 200, 90, 20);

        final JLabel label
                = new JLabel();
        label.setBounds(600, 430, 500, 30);
        JButton b = new JButton("Show");
        b.setBounds(1000, 300, 80, 30);

        final DefaultListModel<String> li1
                = new DefaultListModel<>();

        li1.addElement("CSE(2, 50, 000)");
        li1.addElement("ECE(2, 50, 000)");
        li1.addElement("EEE(2, 50, 000)");
        li1.addElement("IT(2, 50, 000)");
        li1.addElement("AERO(2, 50, 000)");
        li1.addElement("MCT(3, 50, 000)");
        li1.addElement("AUTO(3, 50, 000)");
        li1.addElement("CHEMICAL(3, 50, 000)");
        li1.addElement("BIOTECH(3, 50, 000)");
        li1.addElement("CIVIL(3, 50, 000)");
        li1.addElement("MECH(3, 50, 000)");

        final JList<String> list1
                = new JList<>(li1);

        list1.setBounds(600, 300, 125, 125);

        DefaultListModel<String> li2
                = new DefaultListModel<>();

        li2.addElement(
                "2 SHARE(1, 50, 000)");
        li2.addElement(
                "3 SHARE(1, 40, 000)");
        li2.addElement(
                "5 SHARE(1, 20, 000)");
        li2.addElement(
                "8 SHARE(1, 10, 000)");
        li2.addElement(
                "BUS(40, 000)");
        li2.addElement("SELF(0)");

        final JList<String> list2
                = new JList<>(li2);
        list2.setBounds(
                800, 300, 125, 125);

        JButton Receipt
                = new JButton("Generate Receipt");
        Receipt.setBounds(600, 490, 150, 30);
        JButton b2 = new JButton("Reset");
        b2.setBounds(750, 490, 150, 30);
        JButton Print = new JButton("Print");
        Print.setBounds(900, 490, 150, 30);

        area2 = new JTextArea();
        area2.setBounds(600, 540, 450, 240);

        add(l1);
        add(l2);
        add(l3);
        add(l4);
        add(l5);
        add(l6);
        add(l7);
        add(l8);
        add(l9);
        add(l10);
        add(l11);
        add(l12);
        add(l13);
        add(l14);
        add(tf1);
        add(tf2);
        add(tf3);
        add(tf4);
        add(tf5);
        add(tf7);
        add(tf8);
        add(area1);
        add(area2);
        add(l15);
        add(rb1);
        add(rb2);
        add(rb3);
        add(rb4);
        add(r5);
        add(r6);
        add(cb);
        add(cb3);
        add(cb1);
        add(cb2);
        add(list1);
        add(list2);
        add(b);
        add(label);
        add(Receipt);
        add(b2);
        add(Print);

        b.addActionListener(new ActionListener() {

            // Method to display the data
            // entered in the text fields
            public void actionPerformed(ActionEvent e)
            {
                String data = "";
                if (list1.getSelectedIndex() != -1) {
                    data = "You had selected the Group:"
                            + list1.getSelectedValue();
                    label.setText(data);
                }
                if (list2.getSelectedIndex() != -1) {
                    data += " and Hostel with the "
                            + "facility of: ";

                    for (Object frame :
                            list2.getSelectedValues()) {
                        data += frame + " ";
                    }
                }
                label.setText(data);
            }
        });

        // Reset the text fields
        b2.addActionListener(
                new ActionListener() {
                    public void actionPerformed(
                            ActionEvent e)
                    {
                        area2.setText("");
                        area1.setText(" ");
                        tf1.setText("");
                        tf2.setText("");
                        tf3.setText("");
                        tf4.setText("");
                        tf5.setText("");
                        tf6.setText(" ");
                    }
                });
        Print.addActionListener(
                new ActionListener() {
                    public void actionPerformed(
                            ActionEvent e)
                    {
                        try {
                            area2.print();
                        }
                        catch (java.awt.print
                                .PrinterException a) {
                            System.err.format(
                                    "NoPrinter Found",
                                    a.getMessage());
                        }
                    }
                });
        Receipt.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e)
            {

                area2.setText(
                        "--------------------"
                                + "-----------XYZ EDUCATIONAL INSTITUTIONS----"
                                + "--------------------"
                                + "----------"
                                + "---------\n");

                area2.setText(area2.getText()
                        + "Student Name: "
                        + tf1.getText()
                        + "\n");
                area2.setText(area2.getText()
                        + "Father's Name: "
                        + tf2.getText()
                        + "\n");
                area2.setText(area2.getText()
                        + "Register No : "
                        + tf3.getText()
                        + "\n");
                area2.setText(area2.getText()
                        + "Email ID: "
                        + tf4.getText()
                        + "\n");
                area2.setText(area2.getText()
                        + "Contact Number: "
                        + tf5.getText()
                        + "\n");
                area2.setText(area2.getText()
                        + "Department Chosen :  "
                        + cb.getSelectedItem()
                        .toString()
                        + "\n");

                if (rb1.isSelected()) {
                    area2.setText(area2.getText()
                            + "Interested to join in: " + " Engineering "
                            + "and Technology\n");
                }
                if (rb2.isSelected()) {
                    area2.setText(area2.getText()
                            + "Interested to join in: "
                            + "Arts and Sciences\n");
                }
                if (rb3.isSelected()) {
                    area2.setText(area2.getText()
                            + "Wants to be a "
                            + "Hosteller \n");
                }
                if (rb4.isSelected()) {
                    area2.setText(area2.getText()
                            + "Wants to be a "
                            + "Day Scholar \n");
                }
                area2.setText(area2.getText()
                        + "Had chosen: "
                        + list1.getSelectedValue()
                        .toString()
                        + "\n");
                area2.setText(area2.getText()
                        + "Had chosen: "
                        + list2.getSelectedValue()
                        .toString()
                        + "\n");

                int index2 = list2.getSelectedIndex();
                area2.setText(area2.getText()+"                             "+" Total amount to be paid "+" will be informed to you using e-mail/post\n ");

                if (e.getSource() == Receipt) {
                    try {
                        FileWriter fw
                                = new FileWriter(
                                "java.txt", true);
                        fw.write(area2.getText());
                        fw.close();
                    }
                    catch (Exception ae) {
                        System.out.println(ae);
                    }
                }

                JOptionPane.showMessageDialog(
                        area2, "Data stored in Server Successfully !");
            };
        });
        addWindowListener(
                new WindowAdapter() {
                    public void windowClosing(
                            WindowEvent we)
                    {
                        System.exit(0);
                    }
                });
        setSize(800, 800);
        setLayout(null);
        setVisible(true);
        setBackground(Color.lightGray);
    }
    public static void main(String[] args)
    {
        new College();
    }
}

Answer 1

绝对定位

这是：

    l1.setBounds(550, 100, 250, 20);

像这样的线条是不理想的。根据不同的窗口大小，绝对定位将无法缩放控件及其位置。在阅读关于布局的文章之后再考虑一下你的方法。与其设置边界，不如指定布局和边框宽度等。

成员

没有理由储存这些：

JLabel l1, l2, l3, l4,
        l5, l6, l7, l8,
        l9, l10, l12, l13,
        l14, l11, l15;

作为班上的成员。应该在函数级别声明它们。当它们超出范围时，它们不会消失；Frame将保留对它们的引用，但您不必这样做。

变量名

特别是对于像f1这样的重要变量--但也可能是所有其他变量--您将希望给它一个更有意义的名称，比如fileChooser。

分组add

与其一刀切地发布您的adds，我认为更容易理解的是重新安排这些内容，使它们在各自的控件声明后直接发生。

        l1 = new JLabel("Fee Report");
        l1.setBounds(550, 100, 250, 20);
        add(l1);

动作侦听器

考虑到操作侦听器方法的长度，应该将这些方法的主体移到类上的方法，而不是在您创建的匿名ActionListener对象上。

Answer 2

除了@Reinderien给出的有价值的技术提示之外，我还想评论一下您的代码结构。

在一个类中(甚至在该类的构造函数中)，您正在做所有事情：

• 创建用户界面(new JLabel()、setBounds()、add()等)
• 获取用户交互(addActionListener())
• 执行业务逻辑(例如生成各种报告)
• 展示结果(print()、setText()等)

我通常希望像您这样的应用程序至少分为两个主要部分：

• 业务逻辑，由与您正在使用的现实世界概念相对应的类组成，例如Student、Group、Course、Year。不应该有任何用户界面元素(没有来自javax.swing、java.awt、System.out等)。在那里，您应该找到描述学生、组等的字段，以及必要的操作(例如，在类Group中，一个方法，如add(Student student)，修改组的字段，现在包含多一个学生)。
• 用户界面，包括向用户展示应用程序当前状态和获取他的命令所需的一切。通过调用业务逻辑来执行它们。

如果您以这种方式组织代码，您将获得一些好处：

• 您的代码更具可读性。如果您想知道将学生添加到组中意味着什么，您可以在Group商务类中找到它。没有必要跳过Swing代码，在其中获取JLabel内容并向其他JLabels添加文本。UI类也是如此。他们只是定义了如何与用户交互，例如，当用户按下这个或那个按钮时，您想要将一个学生添加到一个组中，而不管它是如何在内部工作的。这是业务逻辑的责任。
• 你获得了更好的可重用性。也许你以后想在服务器上部署你的应用程序，让用户在他们的浏览器上进行交互。然后，您可以保持业务逻辑不变，“只要”编写一个新的基于web的前端，替换或添加到Swing用户界面。