Question

我尝试使用MySQL数据库验证java中的用户（登录）。我希望能够在控制台中执行此操作。这就是我到目前为止：我的主要课程 -

import java.util.Scanner;

public class main {
    public static void main(String args[]){
        if (args.length < 2)
            return;
        login meth = new login();
        Scanner in = new Scanner(System.in);

        String username;
        String password;

        System.out.println("");
        System.out.println("Username: ");
            username = in.next();
        System.out.println("2. Account Holder");
            password = in.next();
        System.out.println("");
        meth.loginDetails(username, password);


        login checker = new login();
        boolean rc = checker.loginDetails(args[0], args[1]);


        System.out.println("The result is: " + Boolean.toString(rc));

        in.close();   
    }

}

这是我的课程，我尝试连接数据库并进行查询。

import java.sql.*;

public class login {
    public void databaseConnection(){ //swapping index a and index b around
        try     {
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = null;
            conn = DriverManager.getConnection("jdbc:mysql://localhost/loginTest","root", "");
            System.out.println("Database is connected !");
            conn.close();
        }
        catch(Exception e){
            System.out.println("Do not connect to DB - Error:"+e);
        }
    }


    static final String CONN_URL = "jdbc:mysql://localhost/loginTest";
    static final String DB_USER = "root";
    static final String DB_PASSWORD = "";

    public boolean loginDetails(String accountNumber, String password){
        Connection con = null;
        Statement stmt = null;
        ResultSet rs = null;

        boolean passwdOK = false;

        try {
            // Establish the connection.
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            con = DriverManager.getConnection(CONN_URL, DB_USER, DB_PASSWORD);

            // Create and execute an SQL statement
            String sqlst = "SELECT Password FROM customer " +
                                 " WHERE Account Number = '" + accountNumber + "'";

            stmt = con.createStatement();
            rs = stmt.executeQuery(sqlst);

            // Check the return data
            if (rs.next()) {
                String passwdSaved = rs.getString(1).trim();
                if (passwdSaved.equals(password.trim()))
                    passwdOK = true;
            }

            rs.close();
            stmt.close();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        finally {
            if (con != null) try { con.close(); } catch(Exception e) {}
        }

        return passwdOK;
    }
}

我的数据库名为Customer，单独的列称为帐号，密码。

在我运行该程序时，它立即被终止。没有显示任何打印行。

所以我的问题是我如何得到一个真或假的结果，用户名和密码是匹配的。如果它是假的，让他们重试，如果它的真正负载切换菜单？

Answer 1

首先改变

boolean rc = checker.loginDetails(args[0], args[1]);

到

boolean rc = checker.loginDetails(username, password);

如果您没有使用参数运行此程序，则args [0]和args [1]将抛出ArrayIndexOutOfBoundException

如何使用MySQL数据库对用户进行身份验证？

1 个答案: