在Java中使用相同的jButton插入和更新數據到MySQL

Question

我正在構建我的第一個Java應用程序。我創建了一個名爲SAVE和UPDATE的獨立按鈕，分別將新數據插入MySQL數據庫和更新修改。兩個按鈕都可以正常工作，但我現在正在考慮將兩個功能組合到一個按鈕中。我該如何解決它？

下面是我的代碼爲單獨的按鈕，完美，但獨立工作;

保存功能

public void actionPerformed(ActionEvent arg0) { 

try{ 

String sql ="Insert into attendance (counseleeID,attendanceDate,present) values (?,?,?)"; 

       pst=conn.prepareStatement(sql); 
       pst.setString(1, comboBoxCounseleeID.getSelectedItem().toString()); 
       pst.setString(2, ((JTextField)dateChooser.getDateEditor().getUiComponent()).getText()); 
       pst.setString(3, comboBoxPresent.getSelectedItem().toString()); 
       pst.execute(); 


       JOptionPane.showMessageDialog(null, "Saved"); 

       comboBoxCounseleeID.setSelectedItem(null); 
       ((JTextComponent) dateChooser.getDateEditor().getUiComponent()).setText(null); //review 
       comboBoxPresent.setSelectedItem(null); 


        }   

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

      } 

      finally { 
        try{ 
         rs.close(); 
          pst.close(); 
         // conn.close(); 
         } 
         catch(Exception e) { 
             } 
          } 
       Update_table(); 
     } 

更新功能

public void actionPerformed(ActionEvent arg0) { 

int p =JOptionPane.showConfirmDialog(null, "Are you sure you want to save these changes?","Update 
    Warning",JOptionPane.YES_NO_OPTION); 
      if(p==0){ 
      try { 
       String s1= comboBoxCounseleeID.getSelectedItem().toString(); 
       String s2= ((JTextField)dateChooser.getDateEditor().getUiComponent()).getText(); 
       String s3= comboBoxPresent.getSelectedItem().toString(); 

String sql ="UPDATE attendance SET counseleeID='"+s1+"',attendanceDate='"+s2+"',present='"+s3+"' 
WHERE (counseleeID='"+s1+"' AND attendanceDate='"+s2+"') "; 
       pst = conn.prepareStatement(sql); 
       pst.execute(); 


       JOptionPane.showMessageDialog(null, "Updated"); 

       comboBoxCounseleeID.setSelectedItem(null); 
       ((JTextComponent) dateChooser.getDateEditor().getUiComponent()).setText(""); //review 
       comboBoxPresent.setSelectedItem(""); 


      } catch (Exception e2) { 
       JOptionPane.showMessageDialog(null, e2); 
      } 

      finally { 
        try{ 
         rs.close(); 
          pst.close(); 
         // conn.close(); 
         } 
         catch(Exception e2) { 
             } 
          } 
       Update_table(); 
      } 
     } 

Answer 1

按照您的意見我已經寫了一小段代碼，這將有助於你。考慮你的表，因爲這

----------------------------------------- 
| id  | name  | salary  | 
+----------+-------------+--------------+ 
| 1  | abc   | 2000   | 
+----------+-------------+--------------+ 
| 2  | kbc   | 3000   | 
+----------+-------------+--------------+ 

表名：EMP 使用下面的代碼：

JButton btn = new JButton("Save"); 
btn.addActionListener((ActionEvent e)->{ 
     //assuming that you have already create the connection to database 
     PreparedStatement ps = con.PreparedStatement("select * from emp where id=?"); 
     ps.setInt(1,yourInput); 
     ResultSet rs = ps.executeQuery(); 
     if(rs.hasNext()) // means record is already available (i.e. Update record) 
     { 
      //update your record here 
     } 
     else   // means no record available (i.e. insert a record) 
     { 
      //insert you record here 
     } 
});