用java做一个UI界面，以便能够打开学生信息的文件，以表格形式查看文件内容，并能够修改学生信息的内容并保存。写出该程序的代码

在Java中创建一个用户界面(UI)来读取、显示和编辑学生信息通常涉及到Swing库或者JavaFX。以下是一个基本的示例，使用Swing来实现一个简单的窗口，它包含一个JTable用于显示和编辑数据。假设我们有一个包含学号、姓名和成绩的学生信息类。

首先，创建一个Student类：

public class Student {
    private int id;
    private String name;
    private double grade;

    // getters and setters
    public int getId() { return id; }
    public void setId(int id) { this.id = id; }
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public double getGrade() { return grade; }
    public void setGrade(double grade) { this.grade = grade; }

    // toString for JTable display
    @Override
    public String toString() {
        return "ID: " + id + ", Name: " + name + ", Grade: " + grade;
    }
}

然后，创建一个简单的Swing UI:

import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import java.awt.*;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class StudentInfoGUI extends JFrame {

    private JTable jTable;
    private DefaultTableModel model;

    public static void main(String[] args) {
        EventQueue.invokeLater(() -> {
            try {
                StudentInfoGUI frame = new StudentInfoGUI();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
    }

    public StudentInfoGUI() {
        setTitle("Student Information");

        // Create a table model
        model = new DefaultTableModel(new Object[]{"ID", "Name", "Grade"}, 0);

        // Load data from file
        loadFromFile("students.txt");

        // Create the table
        jTable = new JTable(model);
        jTable.getColumnModel().getColumn(0).setPreferredWidth(60);
        jTable.getColumnModel().getColumn(1).setPreferredWidth(150);
        jTable.getColumnModel().getColumn(2).setPreferredWidth(80);
        
        // Add table to scroll pane
        JScrollPane jScrollPane = new JScrollPane(jTable);
        add(jScrollPane);

        setSize(400, 300);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    private void loadFromFile(String fileName) {
        BufferedReader reader = null;
        try {
            reader = new BufferedReader(new FileReader(fileName));
            String line;
            while ((line = reader.readLine()) != null) {
                String[] parts = line.split(",");
                model.addRow(new Object[]{parts[0], parts[1], Double.parseDouble(parts[2])});
            }
        } catch (IOException e) {
            System.out.println("Error reading file");
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    // Implement editing functionality here
    public void updateRow(int row, String newName, double newGrade) {
        model.setValueAt(newName, row, 1);
        model.setValueAt(newGrade, row, 2); // Assuming index 2 is for grades
    }

    // Save changes back to file
    public void saveToFile() {
        BufferedWriter writer = null;
        try {
            writer = new BufferedWriter(new FileWriter("students.txt"));
            for (int i = 0; i < model.getRowCount(); i++) {
                String[] rowData = (String[])model.getValueAt(i, columnModel.getColumnIds());
                writer.write(rowData[0] + "," + rowData[1] + "," + rowData[2] + "\n");
            }
        } catch (IOException e) {
            System.out.println("Error saving file");
        } finally {
            if (writer != null) {
                try {
                    writer.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

这个程序会从`students.txt`文件加载数据到JTable中，允许用户通过点击单元格进行编辑，并在`saveToFile()`函数中将更改保存回去。注意这只是一个基础示例，实际应用可能需要添加更多的错误处理和用户交互细节。