Question

过去几个小时我一直在挠头，想知道出了什么问题。我想在我的访问数据库上编辑一个日期/时间格式，它只是让我不知道为什么我无法更新它。这是我的代码，我会解释。。

这是Main类，其中有一个按钮表示更新，单击时将导致另一个名为UpdateBooking_Run（）的类

public MainInterface() {
    JButton updateBookings = new JButton("UPDATE");
    updateBookings.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            UpdateBooking_Run ub = new UpdateBooking_Run();
            ub.setVisible(true);
        }
    });
 }

这是UpdateBooking_Run（），没有文本框只有这个类里面的按钮......正如你从字符串中看到的，我将日期转换为java.sql.Date

public class UpdateBooking_Run extends JFrame {
   public static java.sql.Date sqldate;
   public UpdateBooking_Run() {
      JButton btnAdd = new JButton("UPDATE");
       btnAdd.addActionListener(new ActionListener() {
          public void actionPerformed(ActionEvent arg0) {
            try {
                Integer.parseInt(yearBookings.getText().trim());
            }
            catch (NumberFormatException na) {
                JOptionPane.showMessageDialog(null, "Please input year", "Error", JOptionPane.ERROR_MESSAGE);

            }

            DateFormat df = new SimpleDateFormat("yyyy/MM/dd");
            String mu = monthBookings.getSelectedItem().toString();
            String da = dayBookings.getSelectedItem().toString();
            String ye = yearBookings.getText().trim();

            String dat =  ye + "/" + mu + "/" + da ;

            java.util.Date date = null;

            try {
                date = df.parse(dat);
            } catch (ParseException e) {
                e.printStackTrace();
            }
            sqldate = new java.sql.Date(date.getTime());

            try {
                UpdateConn_Run uc = new UpdateConn_Run();
                uc.updateDate();
            }
            catch (Exception en) {
                en.printStackTrace();
            }
          }
       });
     }
  }

正如您在上面的代码中看到的，我将sqldate设置为static主要是因为它在我的其他类上更新了字符串，但我似乎无法更新Date。。

然后这是连接......或者UpdateConn_Run（）

public class UpdateConn_Run {
   Connection con;
   Statement st;
   ResultSet rs;
   StringBuffer results;
   String url = "jdbc:ucanaccess://C://DATABASE//DATA.accdb";   
   PreparedStatement ps;

      public void updateBooking() {
        try {
           int i = 1;
           UpdateBooking_Run ubr = new UpdateBooking_Run();
           MainInterface mi = new MainInterface();

        Date da = UpdateBooking_Run.sqldate;

        con = DriverManager.getConnection(url);
        //theres actually an uneditable textbox in MainInterface that shows the ID of the selected row
        int id = Integer.parseInt(mi.idstringBookings);
        String sql = "UPDATE bookings SET date ='"+da+"' WHERE ID ='"+id+"'";
        ps = con.prepareStatement(sql);
        ps.executeUpdate();

        ps.close();
        con.close();

        if (i == 1) {
            JOptionPane.showMessageDialog(null, "Database has been updated please click Refresh");

        }

    }

    catch (Exception e) {
            e.printStackTrace();
    }
}

我似乎也得到错误......

net.ucanaccess.jdbc.UcanaccessSQLException: data exception: invalid datetime format
at net.ucanaccess.jdbc.UcanaccessPreparedStatement.executeUpdate(UcanaccessPreparedStatement.java:261)
at interfaceSystem.UpdateConn_Run.updateBooking(UpdateConn_Run.java:109)
at interfaceSystem.UpdateBooking_Run$2.actionPerformed(UpdateBooking_Run.java:284)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

但它仍然让我感到困惑。。

它表示无效的日期时间格式，所以我继续并一次又一次地更改了格式。即使尝试过MS Access中的格式问题仍然存在。
试图不把日期作为静态。我得到＆＃34; null＆＃34;。
有人可以解释为什么静态用于更新PreparedStatements中的数据库吗？我仍然困惑于今天...（我班上的每个人似乎都在使用它，虽然我不知道为什么）

我很抱歉我的英语。我不是母语人士所以如果你对语法有疑问我会很感激...

Answer 1

由于您使用的是PreparedStatement，因此您应该使用占位符，并且您的代码应如下所示：

query = "UPDATE bookings SET date = ? WHERE id = ?";

preparedStatement = con.prepareStatement(query);
preparedStatement.setDate(1, da);
preparedStatement.setInt(2, id);
preparedStatement.executeUpdate();

由于您将Date对象包含在String中，因此将使用其toString()方法对其进行解析，您的语句将如下所示：

"UPDATE bookings SET date = 2000-01-12 WHERE id = 22"

Answer 2

我不做Java，但是你的最终SQL for Access必须如下所示：

"UPDATE bookings SET date = #2017/03/21# WHERE ID = '1'";

或者，如果ID是数字：

"UPDATE bookings SET date = #2017/03/21# WHERE ID = 1";

因此，像：

//datestring = da formatted as "2017/03/20"
String sql = "UPDATE bookings SET date =#"+datestring+"# WHERE ID ='"+id+"'";

使用PreparedStatement将java.sql.Date更新到数据库中

2 个答案: