mysql中的登录表单

Question

我正在使用Mysql netbeans。我已经创建了一个db表"userdetails_summertrainingproject“。在登录表单中，我有两个文件要填写，一个是"UUId_JTextField“，另一个是"Password1_JPasswordField”。我想比较一下，用户输入的密码值与用户输入的特定UUId的db中的密码值相同。UUid是独一无二的。

try{
                Class.forName("com.mysql.jdbc.Driver");
                Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql","root","");
                    String query = "SELECT password FROM userdetails_summertrainingproject WHERE UUId=?;";
                    PreparedStatement preparedStatement = conn.prepareStatement(query);
                    preparedStatement.setString(1,UUId_JTextField.getText());
                    ResultSet rs = preparedStatement.executeQuery();
                    char[] password1 = Password1_JPasswordField.getPassword();
                    String pass1 = new String(password1);
                    if(rs.getString(query)==pass1){
                        JOptionPane.showMessageDialog(null, "Logged in successfully");
                    }
            }

            catch(Exception e){
                System.out.println("Exception in Login:"+e.getMessage());
            }

以上是我正在使用的代码。例外是：

Login中的异常:列“从userdetails_summertrainingproject选择密码UUId=？；”未找到。

Answer 1

试试这段代码，你错过了rs.next()

    try {
        Class.forName("com.mysql.jdbc.Driver");
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3307/mysql", "root", "");
        String query = "SELECT password FROM userdetails_summertrainingproject WHERE UUId=?;";
        PreparedStatement preparedStatement = conn.prepareStatement(query);
        preparedStatement.setString(1, UUId_JTextField.getText());
        ResultSet rs = preparedStatement.executeQuery();
        char[] password1 = Password1_JPasswordField.getPassword();
        String pass1 = Arrays.toString(password1);
        rs.next();
        if (rs.getString("password").equals(pass1)) {
            JOptionPane.showMessageDialog(null, "Logged in successfully");
        }
    } catch (Exception e) {
        e.printStackTrace();
    }

我认为使用另一种方法来获取连接字符串是比较容易的。否则，您必须一次又一次地编写下面的代码。

Class.forName("com.mysql.jdbc.Driver");
    Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3307/mysql", "root", ""); 

编辑：

public static void main(String[] args) {
    try {
        Class.forName("com.mysql.jdbc.Driver");
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql", "root", "");
        String query = "SELECT UUId FROM userdetails_summertrainingproject;";
        PreparedStatement preparedStatement = conn.prepareStatement(query);
        ResultSet rs = preparedStatement.executeQuery();
        rs.next();
        String UUId = rs.getString("UUId");
        System.out.println("UUId " + UUId);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

创建一个类并添加以下代码。然后检查这段代码是否有效。请确保端口，数据库名称，用户和密码是正确的。

如果这是给com.mysql.jdbc.CommunicationsException: Communications link failure。很可能您的端口不正确。

​

我正在使用这两个图书馆。

Answer 2

try{
      Class.forName("com.mysql.jdbc.Driver");
      Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql","root","");
      String query="SELECT password FROM tryingtable WHERE name=?;";
      PreparedStatement prepstmt=conn.prepareStatement(query);
      prepstmt.setString(1,jtf.getText());
      ResultSet rs=prepstmt.executeQuery();
      rs.next();
      String result=rs.getString("password");;
      char[] pass = jpf.getPassword();
      String password1= new String(pass);
      if(result.equals(password1))
      JOptionPane.showMessageDialog(null, "go!!");
       else
       JOptionPane.showMessageDialog(null, "no!!");

    }

      catch(Exception e){
      System.out.println("Exception:"+e.getMessage());
      e.getStackTrace();
      }

Answer 3

当您要将密码字段与文本字段进行比较时，请使用

char[] pass_char = passwordField.getPassword();
String pass_string = new String(pass_char);

以上代码将以字符串形式给出密码字段值，然后

if(pass_string.equals(textfield))
JOptionPane.showMessageDialog("Password match");
else
JOptionPane.showMessageDialog("Password did not match");