用java开发一个在线学习学生系统中的题库管理部分，并要有GUI部分。其中管理员（manager）能增删查改改题库。

好的，您可以按照以下步骤来实现在线学习学生系统中的题库管理部分：

1. 创建数据库表

首先，您需要创建一个名为“题库（question）”的数据库表，其中包含以下字段：

- id: 题目ID，自增长的整数类型。
- content: 题目内容，VARCHAR 类型。
- answer: 答案，VARCHAR 类型。
- type: 题目类型，VARCHAR 类型。

2. 创建 Java 类

接下来，您需要创建一个名为“Question”的 Java 类，该类将映射到数据库表中的每个字段。您可以使用以下代码开始：

public class Question {
    private int id;
    private String content;
    private String answer;
    private String type;

    // getter and setter methods
}

3. 创建 DAO 类

接下来，您需要创建一个名为“QuestionDAO”的 Java 类，该类用于执行与数据库相关的操作。您可以使用以下代码开始：

public class QuestionDAO {
    private Connection connection;

    public QuestionDAO() {
        // 获取数据库连接
        connection = getConnection();
    }

    // 获取数据库连接
    private Connection getConnection() {
        Connection conn = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/your_database_name", "your_username", "your_password");
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }

    // 增加题目
    public void addQuestion(Question question) {
        String sql = "INSERT INTO question (content, answer, type) VALUES (?, ?, ?)";
        try {
            PreparedStatement ps = connection.prepareStatement(sql);
            ps.setString(1, question.getContent());
            ps.setString(2, question.getAnswer());
            ps.setString(3, question.getType());
            ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 删除题目
    public void deleteQuestion(int id) {
        String sql = "DELETE FROM question WHERE id=?";
        try {
            PreparedStatement ps = connection.prepareStatement(sql);
            ps.setInt(1, id);
            ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 修改题目
    public void updateQuestion(Question question) {
        String sql = "UPDATE question SET content=?, answer=?, type=? WHERE id=?";
        try {
            PreparedStatement ps = connection.prepareStatement(sql);
            ps.setString(1, question.getContent());
            ps.setString(2, question.getAnswer());
            ps.setString(3, question.getType());
            ps.setInt(4, question.getId());
            ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 查询题目
    public Question getQuestion(int id) {
        Question question = null;
        String sql = "SELECT * FROM question WHERE id=?";
        try {
            PreparedStatement ps = connection.prepareStatement(sql);
            ps.setInt(1, id);
            ResultSet rs = ps.executeQuery();
            if (rs.next()) {
                question = new Question();
                question.setId(rs.getInt("id"));
                question.setContent(rs.getString("content"));
                question.setAnswer(rs.getString("answer"));
                question.setType(rs.getString("type"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return question;
    }

    // 查询所有题目
    public List<Question> getAllQuestions() {
        List<Question> questions = new ArrayList<>();
        String sql = "SELECT * FROM question";
        try {
            Statement stmt = connection.createStatement();
            ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                Question question = new Question();
                question.setId(rs.getInt("id"));
                question.setContent(rs.getString("content"));
                question.setAnswer(rs.getString("answer"));
                question.setType(rs.getString("type"));
                questions.add(question);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return questions;
    }
}

4. 创建 GUI 界面

最后，您需要创建一个名为“QuestionManager”的 GUI 界面，该界面包含一个表格和一组按钮，用于执行增加、删除、修改和查询操作。您可以使用以下代码开始：

public class QuestionManager extends JFrame {
    private JTable table;
    private QuestionTableModel model;
    private QuestionDAO dao;

    public QuestionManager() {
        super("题库管理");

        dao = new QuestionDAO();
        model = new QuestionTableModel(dao.getAllQuestions());
        table = new JTable(model);

        JScrollPane scrollPane = new JScrollPane(table);
        getContentPane().add(scrollPane, BorderLayout.CENTER);

        JPanel buttonPanel = new JPanel();
        getContentPane().add(buttonPanel, BorderLayout.SOUTH);

        JButton addButton = new JButton("增加");
        addButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                QuestionDialog dialog = new QuestionDialog(QuestionManager.this, "增加题目");
                dialog.setVisible(true);
                if (dialog.isOK()) {
                    Question question = dialog.getQuestion();
                    dao.addQuestion(question);
                    model.addQuestion(question);
                }
            }
        });
        buttonPanel.add(addButton);

        JButton deleteButton = new JButton("删除");
        deleteButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                int selectedRow = table.getSelectedRow();
                if (selectedRow != -1) {
                    int id = (int) table.getValueAt(selectedRow, 0);
                    dao.deleteQuestion(id);
                    model.deleteQuestion(selectedRow);
                }
            }
        });
        buttonPanel.add(deleteButton);

        JButton updateButton = new JButton("修改");
        updateButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                int selectedRow = table.getSelectedRow();
                if (selectedRow != -1) {
                    int id = (int) table.getValueAt(selectedRow, 0);
                    Question question = dao.getQuestion(id);
                    QuestionDialog dialog = new QuestionDialog(QuestionManager.this, "修改题目", question);
                    dialog.setVisible(true);
                    if (dialog.isOK()) {
                        question = dialog.getQuestion();
                        dao.updateQuestion(question);
                        model.updateQuestion(selectedRow, question);
                    }
                }
            }
        });
        buttonPanel.add(updateButton);

        JButton queryButton = new JButton("查询");
        queryButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String type = JOptionPane.showInputDialog(QuestionManager.this, "请输入题目类型");
                if (type != null && !type.isEmpty()) {
                    List<Question> questions = dao.getAllQuestions();
                    List<Question> filteredQuestions = new ArrayList<>();
                    for (Question question : questions) {
                        if (question.getType().equals(type)) {
                            filteredQuestions.add(question);
                        }
                    }
                    model.setQuestions(filteredQuestions);
                }
            }
        });
        buttonPanel.add(queryButton);

        setSize(600, 400);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new QuestionManager().setVisible(true);
            }
        });
    }
}

5. 创建表格模型类

最后，您需要创建一个名为“QuestionTableModel”的表格模型类，该类用于显示所有题目。您可以使用以下代码开始：

public class QuestionTableModel extends AbstractTableModel {
    private static final String[] COLUMN_NAMES = {"ID", "内容", "答案", "类型"};
    private List<Question> questions;

    public QuestionTableModel(List<Question> questions) {
        this.questions = questions;
    }

    public void setQuestions(List<Question> questions) {
        this.questions = questions;
        fireTableDataChanged();
    }

    public void addQuestion(Question question) {
        questions.add(question);
        fireTableRowsInserted(questions.size() - 1, questions.size() - 1);
    }

    public void deleteQuestion(int rowIndex) {
        questions.remove(rowIndex);
        fireTableRowsDeleted(rowIndex, rowIndex);
    }

    public void updateQuestion(int rowIndex, Question question) {
        questions.set(rowIndex, question);
        fireTableRowsUpdated(rowIndex, rowIndex);
    }

    @Override
    public int getRowCount() {
        return questions.size();
    }

    @Override
    public int getColumnCount() {
        return COLUMN_NAMES.length;
    }

    @Override
    public String getColumnName(int columnIndex) {
        return COLUMN_NAMES[columnIndex];
    }

    @Override
    public Class<?> getColumnClass(int columnIndex) {
        switch (columnIndex) {
            case 0:
                return Integer.class;
            case 1:
            case 2:
            case 3:
                return String.class;
            default:
                return Object.class;
        }
    }

    @Override
    public Object getValueAt(int rowIndex, int columnIndex) {
        Question question = questions.get(rowIndex);
        switch (columnIndex) {
            case 0:
                return question.getId();
            case 1:
                return question.getContent();
            case 2:
                return question.getAnswer();
            case 3:
                return question.getType();
            default:
                return null;
        }
    }
}

至此，您已经成功实现了在线学习学生系统中的题库管理部分，并且具有GUI界面，管理员（manager）能增删查改题库。