java - 如何从 Java Netbeans 中的 GUI 更新表？

Question

我正在使用 Java Netbeans 设计 GUI，并尝试将 GUI 字段中的值插入到表中。它显示没有错误，但没有插入任何内容。这是我的代码:

Statement stmt = null;
try {

    String sql = "Insert into Elective (subject_code,topic,syllabus,credit,Expert_ID,startsession,endsession) values (?,?,?,?,?,?,?)";
    pst = conn.prepareStatement(sql);
    String subject = Subject_code.getSelectedItem().toString();
    pst.setString(1, subject);
    pst.setString(2, topic.getText());
    pst.setString(3, syllabus.getText());
    pst.setString(4, credit.getText());

    String Expert = Expert_ID.getSelectedItem().toString();
    pst.setString(5, Expert);

    int y1 = startsession.getYear();
    int y2 = endsession.getYear();
    pst.setInt(6, y1);
    pst.setInt(7, y2);
    //ResultSet executeQuery = pst.executeQuery();
    stmt = conn.createStatement();
    ResultSet rs = stmt.executeQuery("SELECT * FROM Elective;");
    while (rs.next()) {
        String subject_code1 = rs.getString("subject_code");
        String topic1 = rs.getString("topic");
        String syllabus1 = rs.getString("syllabus");
        String credit1 = rs.getString("credit");
        String Expert_ID1 = rs.getString("Expert_ID");
        int startsession1 = rs.getInt("startsession");
        int endsession1 = rs.getInt("endsession");
        System.out.println("Subject Code = " + subject_code1);
        System.out.println("Topic = " + topic1);
        System.out.println("Syllabus=" + syllabus1);
        System.out.println("Credit = " + credit1);
        System.out.println("Expert_ID = " + Expert_ID1);
        System.out.println("Start session = " + startsession1);
        System.out.println("End session = " + endsession1);
        System.out.println();
    }
    rs.close();
    stmt.close();

} catch (Exception e) {
    JOptionPane.showMessageDialog(null, e);
}

Answer 1

您应该使用 executeUpdate() 来更新数据库，而不是 executeQuery() 方法，并且 executeUpdate() 不会返回 ResultSet 。

使用

 pst.executeUpdate();

不是

ResultSet executeQuery = pst.executeQuery();//not correct

不知道您为什么评论该行。大概这就是您没有收到任何错误的原因