用Java写一个成绩管理系统，有图形化界面，能实现文件输入输出流

以下是一个简单的成绩管理系统的Java代码，使用了Swing实现图形化界面，并且能够使用文件输入输出流进行数据的读写操作。

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

public class ScoreManagementSystem extends JFrame {
    private JLabel nameLabel, scoreLabel;
    private JTextField nameField, scoreField;
    private JButton addButton, showButton, saveButton, loadButton;
    private JTextArea infoArea;

    public ScoreManagementSystem() {
        super("成绩管理系统");

        // 创建组件
        nameLabel = new JLabel("姓名：");
        scoreLabel = new JLabel("成绩：");
        nameField = new JTextField(10);
        scoreField = new JTextField(10);
        addButton = new JButton("添加");
        showButton = new JButton("显示");
        saveButton = new JButton("保存");
        loadButton = new JButton("读取");
        infoArea = new JTextArea(10, 30);

        // 添加组件
        JPanel panel1 = new JPanel();
        panel1.add(nameLabel);
        panel1.add(nameField);
        panel1.add(scoreLabel);
        panel1.add(scoreField);
        panel1.add(addButton);
        panel1.add(showButton);
        panel1.add(saveButton);
        panel1.add(loadButton);
        add(panel1, BorderLayout.NORTH);
        add(infoArea, BorderLayout.CENTER);

        // 绑定事件
        addButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String name = nameField.getText();
                String scoreStr = scoreField.getText();
                if (name.length() == 0 || scoreStr.length() == 0) {
                    JOptionPane.showMessageDialog(ScoreManagementSystem.this, "请输入姓名和成绩", "错误", JOptionPane.ERROR_MESSAGE);
                    return;
                }
                try {
                    double score = Double.parseDouble(scoreStr);
                    addScore(name, score);
                    infoArea.setText(getAllScores());
                } catch (NumberFormatException ex) {
                    JOptionPane.showMessageDialog(ScoreManagementSystem.this, "请输入正确的成绩", "错误", JOptionPane.ERROR_MESSAGE);
                }
            }
        });

        showButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                infoArea.setText(getAllScores());
            }
        });

        saveButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                JFileChooser fc = new JFileChooser();
                fc.setFileFilter(new FileNameExtensionFilter("文本文件", "txt"));
                int result = fc.showSaveDialog(ScoreManagementSystem.this);
                if (result == JFileChooser.APPROVE_OPTION) {
                    File file = fc.getSelectedFile();
                    try {
                        saveScores(file);
                        JOptionPane.showMessageDialog(ScoreManagementSystem.this, "保存成功", "提示", JOptionPane.INFORMATION_MESSAGE);
                    } catch (IOException ex) {
                        JOptionPane.showMessageDialog(ScoreManagementSystem.this, "保存失败：" + ex.getMessage(), "错误", JOptionPane.ERROR_MESSAGE);
                    }
                }
            }
        });

        loadButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                JFileChooser fc = new JFileChooser();
                fc.setFileFilter(new FileNameExtensionFilter("文本文件", "txt"));
                int result = fc.showOpenDialog(ScoreManagementSystem.this);
                if (result == JFileChooser.APPROVE_OPTION) {
                    File file = fc.getSelectedFile();
                    try {
                        loadScores(file);
                        infoArea.setText(getAllScores());
                        JOptionPane.showMessageDialog(ScoreManagementSystem.this, "读取成功", "提示", JOptionPane.INFORMATION_MESSAGE);
                    } catch (IOException ex) {
                        JOptionPane.showMessageDialog(ScoreManagementSystem.this, "读取失败：" + ex.getMessage(), "错误", JOptionPane.ERROR_MESSAGE);
                    }
                }
            }
        });

        // 设置窗口属性
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(400, 300);
        setLocationRelativeTo(null);
        setVisible(true);
    }

    // 添加一条成绩
    private void addScore(String name, double score) {
        try {
            FileWriter fw = new FileWriter("scores.txt", true);
            fw.write(name + " " + score + "\n");
            fw.close();
        } catch (IOException e) {
            JOptionPane.showMessageDialog(this, "写入文件失败：" + e.getMessage(), "错误", JOptionPane.ERROR_MESSAGE);
        }
    }

    // 获取所有成绩
    private String getAllScores() {
        StringBuilder sb = new StringBuilder();
        try {
            FileReader fr = new FileReader("scores.txt");
            BufferedReader br = new BufferedReader(fr);
            String line;
            while ((line = br.readLine()) != null) {
                sb.append(line).append("\n");
            }
            br.close();
            fr.close();
        } catch (IOException e) {
            JOptionPane.showMessageDialog(this, "读取文件失败：" + e.getMessage(), "错误", JOptionPane.ERROR_MESSAGE);
        }
        return sb.toString();
    }

    // 保存成绩到文件
    private void saveScores(File file) throws IOException {
        FileWriter fw = new FileWriter(file);
        FileReader fr = new FileReader("scores.txt");
        BufferedReader br = new BufferedReader(fr);
        String line;
        while ((line = br.readLine()) != null) {
            fw.write(line + "\n");
        }
        br.close();
        fr.close();
        fw.close();
    }

    // 从文件读取成绩
    private void loadScores(File file) throws IOException {
        FileReader fr = new FileReader(file);
        BufferedReader br = new BufferedReader(fr);
        String line;
        FileWriter fw = new FileWriter("scores.txt");
        while ((line = br.readLine()) != null) {
            fw.write(line + "\n");
        }
        br.close();
        fr.close();
        fw.close();
    }

    public static void main(String[] args) {
        new ScoreManagementSystem();
    }
}

这个成绩管理系统的界面包括姓名、成绩两个输入框，以及添加、显示、保存、读取四个按钮。当用户点击添加按钮时，程序将读取输入框中的姓名和成绩，然后将它们写入到一个文件中。当用户点击显示按钮时，程序将读取文件中的所有成绩，并将它们显示在界面的文本区域中。当用户点击保存按钮时，程序将弹出一个文件选择对话框，用户可以选择一个文件，然后程序将把当前所有成绩写入到该文件中。当用户点击读取按钮时，程序将弹出一个文件选择对话框，用户可以选择一个文件，然后程序将从该文件中读取成绩，并将它们写入到原来的文件中。