根据不同的id开头从数据库更改密码

Question

我有3张桌子（医生，护士，病人），他们都有不同的身份证明开始，医生身份从101开始，护士从102开始，患者从200开始。我想根据他们的id的开头更改密码。在我的JFrame中我有5个JComponents，4个Jtextfields，1个Jbutton 1 Jtextfields用于id（name：idField）1个Jtextfields用于当前密码（name：currentPass）2个Jtextfields用于新密码（name：newPass1，newPass2）1个Jbutton for动作（名称：changeButton）

我在我的代码中做了两种不同的方式，但两者都不适用于我。你能帮我解决这个问题吗？

第一种方式：

private void changeButtonActionPerformed(java.awt.event.ActionEvent evt) {                                             
       id=idField.getText();
       newpass1=newPass1.getText();
       newpass2=newPass2.getText();

        try {
        con = DriverManager.getConnection("jdbc:derby://localhost:1527/hj", "xxx", "xxx");
        st = con.createStatement();

        if (newpass1.equals(newpass2)){


          ResultSet rs = st.executeQuery("update patient set patient_Password="+ newpass1 +" where patient_Id="+id+" and patient_Id like '200%'");  
          JOptionPane.showMessageDialog(this , "Successfully changed", "Patient password successfuly changed !",JOptionPane.PLAIN_MESSAGE);

          ResultSet rs1 = st.executeQuery("update Nurse set nurse_password="+ newpass1 +" where nurse_id="+id+" and nurse_id like '102%'");
            JOptionPane.showMessageDialog(this , "Successfully changed", "Nurse password successfuly changed !",JOptionPane.PLAIN_MESSAGE);

            ResultSet rs2 = st.executeQuery("update doctor set doctor_password="+ newpass1 +" where doctor_id="+id+" and doctor_id like '101%'");
            JOptionPane.showMessageDialog(this , "Successfully changed", "Doctor password successfuly changed !",JOptionPane.PLAIN_MESSAGE);

        } else 
            JOptionPane.showMessageDialog(this , "Not equal", "Your new passwords are not equal!! , try again",JOptionPane.ERROR_MESSAGE );
       }catch (Exception x){
           JOptionPane.showMessageDialog(this, x.getStackTrace());
       }
    }

第二种方式：

 private void changeButtonActionPerformed(java.awt.event.ActionEvent evt) {                                             
       id=idField.getText();
       newpass1=newPass1.getText();
       newpass2=newPass2.getText();

        try {
        con = DriverManager.getConnection("jdbc:derby://localhost:1527/hj", "xxx", "xxx");
        st = con.createStatement();

        if (newpass1.equals(newpass2)){

        if (id.startsWith("200")){
          ResultSet rs = st.executeQuery("update patient set patient_Password="+ newpass1 +" where patient_Id="+id+"");  
          JOptionPane.showMessageDialog(this , "Successfully changed", "Patient password successfuly changed !",JOptionPane.PLAIN_MESSAGE);
        } 
        else if (id.startsWith("102")){
          ResultSet rs = st.executeQuery("update Nurse set nurse_password="+ newpass1 +" where nurse_id="+id+"");
            JOptionPane.showMessageDialog(this , "Successfully changed", "Nurse password successfuly changed !",JOptionPane.PLAIN_MESSAGE);
                }
        else if (id.startsWith("101")){
            ResultSet rs = st.executeQuery("update doctor set doctor_password="+ newpass1 +" where doctor_id="+id+"");
            JOptionPane.showMessageDialog(this , "Successfully changed", "Doctor password successfuly changed !",JOptionPane.PLAIN_MESSAGE);
        }

        } else 
            JOptionPane.showMessageDialog(this , "Not equal", "Your new passwords are not equal!! , try again",JOptionPane.ERROR_MESSAGE );
       }catch (Exception x){
           JOptionPane.showMessageDialog(this, x.getStackTrace());
       }
    }

Answer 1

请使用PreparedStatement！

    if (id.startsWith("200")){
      try (PreparedStatement pstmt = conn.prepareStatement("UPDATE patient SET patient_passwort=? WHERE patient_id=?");) {
          pstmt.setString(1, newpass1);
          pstmt.setString(2, id);
          int rows = pstmt.executeUpdate();

          JOptionPane.showMessageDialog(this , "Successfully changed", 
             "Patient password successfuly changed! (updated rows: "+rows+")", JOptionPane.PLAIN_MESSAGE);
       }
    } 

通过连接查询，您将获得update patient set patient_Password=abcdefghi where patient_Id=200340 and patient_Id like '200%'。未引用新密码（此处为abcdefghi），这对于查询中的字符串是必需的。 patient_id也没有引用，但它可能是一个数字字段，不得引用。

BTW：

• 不需要查询部分patient_id like '200%'。
• 您应该关闭所有PreparedStatement / Statement实例，这可以通过使用try-with-resources（try (PreparedStatement xxx = ...) { ... your code } // closes automatically）来完成。同样适用于Connection和ResultSet。
• 因为id是一个整数，你可能想要这样使用它：int updId = Integer.parseInt(id); ... pstmt.setInt(2, updId); ...

提普：如果你使用Apache commons-dbutils，你会更加轻松。例如org.apache.commons.dbutils.QueryRunner

  QueryRunner r = new QueryRunner();
  int rows = r.update(conn, 
       "UPDATE patient SET patient_passwort=? WHERE patient_id=?",
       newpass1, id);