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尝试设置一个 JDBC 来检查数据库中匹配的用户名和密码，并且当按下登录按钮时，如果匹配的用户被授予访问权限，我在这里有我当前的代码，但我不确定缺少什么当我启动程序时，它似乎没有检查数据库中的正确信息。

更新：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;

public class NewClass extends JFrame {

    private JTextField jtfUsername, jtfPassword;
    private JButton backButton, loginButton;
    private JMenuItem jmiLogin, jmiBack, jmiHelp, jmiAbout;

    NewClass() {
        //create menu bar
        JMenuBar jmb = new JMenuBar();

        //set menu bar to the applet
        setJMenuBar(jmb);

        //add menu "operation" to menu bar
        JMenu optionsMenu = new JMenu("Options");
        optionsMenu.setMnemonic('O');
        jmb.add(optionsMenu);

        //add menu "help"
        JMenu helpMenu = new JMenu("Help");
        helpMenu.setMnemonic('H');
        helpMenu.add(jmiAbout = new JMenuItem("About", 'A'));
        jmb.add(helpMenu);

        //add menu items with mnemonics to menu "options"
        optionsMenu.add(jmiLogin = new JMenuItem("Login", 'L'));
        optionsMenu.addSeparator();
        optionsMenu.add(jmiBack = new JMenuItem("Back", 'B'));

        //panel p1 to holds text fields
        JPanel p1 = new JPanel(new GridLayout(2, 2));
        p1.add(new JLabel("Username"));
        p1.add(jtfUsername = new JTextField(15));
        p1.add(new JLabel("Password"));
        p1.add(jtfPassword = new JPasswordField(15));

        //panel p2 to holds buttons
        JPanel p2 = new JPanel(new FlowLayout());
        p2.add(backButton = new JButton("Back"));
        p2.add(loginButton = new JButton("Login"));

        //Panel with image??????

        //add panels to frame
        JPanel panel = new JPanel(new GridLayout(2, 1));
        panel.add(p1, BorderLayout.CENTER);
        panel.add(p2, BorderLayout.SOUTH);
        add(panel, BorderLayout.CENTER);
        setTitle("Main Page");


        //listners for exit menuitem and button
        jmiBack.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                Welcome welcome = new Welcome();
                welcome.setVisible(true);
                welcome.setSize(500, 500);
                welcome.setLocationRelativeTo(null);
                registerInterface regFace = new registerInterface();
                regFace.setVisible(false);
                NewClass.this.dispose();
                NewClass.this.setVisible(false);
            }
        });

        backButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                Welcome welcome = new Welcome();
                welcome.setVisible(true);
                welcome.setSize(500, 500);
                welcome.setLocationRelativeTo(null);
                registerInterface regFace = new registerInterface();
                regFace.setVisible(false);
                NewClass.this.dispose();
                NewClass.this.setVisible(false);
            }
        });

        //listner for about menuitem
        jmiAbout.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                JOptionPane.showMessageDialog(null,
                        "This is the login panel"
                        + "\n Assignment for University",
                        "About", JOptionPane.INFORMATION_MESSAGE);
            }
        });

        //action listeners for Login in button and menu item
        loginButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                try {
                    usernamecheck.checkLogin(jtfUsername.getText(), jtfPassword.getText()); {
                    System.out.println("User is validated");
               }
                } catch (SQLException se) {
                }
                MainMenu mainmenu = new MainMenu();
                mainmenu.setVisible(true);
                mainmenu.setSize(500, 500);
                mainmenu.setLocationRelativeTo(null);
                registerInterface regFace = new registerInterface();
                regFace.setVisible(false);
                NewClass.this.dispose();
                NewClass.this.setVisible(false);
            }
        });

        jmiLogin.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                MainMenu mainmenu = new MainMenu();
                mainmenu.setVisible(true);
                mainmenu.setSize(500, 500);
                mainmenu.setLocationRelativeTo(null);
                registerInterface regFace = new registerInterface();
                regFace.setVisible(false);
                NewClass.this.dispose();
                NewClass.this.setVisible(false);
            }
        });
    }

    public static void main(String arg[]) {
        log frame = new log();
        frame.setSize(500, 500);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

class usernamecheck {

    static final String DATABASE_URL = "jdbc:mysql://localhost:3306/test";
    static final String USERNAME = "root";
    static final String PASSWORD = "root";

   // launch the application
    public static boolean checkLogin(String username, String password)
            throws SQLException {
        System.out.print("dfdF");

        Connection connection = null; // manages connection
        PreparedStatement pt = null; // manages prepared statement

        // connect to database usernames and query database

尝试 {

        // establish connection to database
        Class.forName("com.mysql.jdbc.Driver").newInstance();
        Connection con = DriverManager.getConnection(DATABASE_URL, "root", "root");

        // query database
        pt = con.prepareStatement("select userName,password from test.person where userName=?");

        // process query results
        pt.setString(1, username);
        ResultSet rs = pt.executeQuery();
        String orgUname = "", orPass = "";
        while (rs.next()) {
            orgUname = rs.getString("userName");
            orPass = rs.getString("password");
        } //end while
        if (orPass.equals(password)) {
            //do something
            return true;
        } else {
            //do something
        }
    }//end try
    catch (Exception e) {
    } //end catch  
    return false;
} //end main

}

4

2 回答 2

0

您的方法中缺少一个return类型checkLogin。您可以返回一个boolean值来验证用户。还要添加一些日志记录/系统输出以确保您的代码中发生了什么。

将您的方法更新为：

// launch the application
    public static boolean checkLogin(String username, String password)
            throws SQLException {
        System.out.print("dfdF");

        Connection connection = null; // manages connection
        PreparedStatement pt = null; // manages prepared statement

        // connect to database usernames and query database
        try {

            // establish connection to database
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            Connection con = DriverManager.getConnection(DATABASE_URL, "root", "root");

            // query database
            pt = con.prepareStatement("select userName,password from test.person where userName=?");

            // process query results
            pt.setString(1, username);
            ResultSet rs = pt.executeQuery();
            String orgUname = "", orPass = "";
            while (rs.next()) {
                orgUname = rs.getString("userName");
                orPass = rs.getString("password");
            } //end while
            if (orPass.equals(password)) {
                //do something
                return true;
                rs.close();
            } else {
                //do something
            }
        }//end try
        catch (Exception e) {
        } //end catch  
        return false;
    } //end main

然后将您的用户检查更新为

           try {
                if(usernamecheck.checkLogin(jtfUsername.getText(), jtfPassword.getText())) {
                    System.out.println("User is validated");
               } else {
                 return;
               }
            } catch (SQLException se) {
            }
于 2013-09-22T04:21:07.350 回答
0

使您的checkLogin方法返回布尔类型并在if (orPass.equals(password)) {块内返回 true。检查方法是否为 true，如果是，则授予访问权限。

于 2013-09-22T04:24:39.563 回答