Intellij：将我的getConnection代码链接到MySQL数据库Web应用程序J2EE时出现问题

如何解决Intellij：将我的getConnection代码链接到MySQL数据库Web应用程序J2EE时出现问题

您好，请将我的登录代码链接到数据库时出现问题。我的sql列名称匹配。我确保了这一点。我使用macOS的mysql工作台创建了连接。

我的设置如下：

   public class User {
    private int userId;
    private String userName;
    private String password;
    private String email;
    private String address;
    private String phone;

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }



    private boolean logged = false;


    public Connection getConnection() throws Exception {
         //My Connection to the database 
         Class.forName("com.mysql.cj.jdbc.Driver");
        
        return DriverManager.getConnection("jdbc:mysql://localhost:3306/OnlineBookStore","root","root");
    }

    public void login()  {
        
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        try {
            connection = getConnection();
            preparedStatement = connection.prepareStatement("select userid,email,phone,address from users where uname = ? and pwd= ?");
            preparedStatement.setString(1,userName);
            preparedStatement.setString(2,password);

            ResultSet rs = preparedStatement.executeQuery();
            
            logged = false;

            if (rs.next()) {
                userId = rs.getInt("userid");
                email = rs.getString("email");
                address = rs.getString("address");
                phone = rs.getString("phone");
                logged = true;

            }

        } catch (Exception ex) {
            System.out.println(ex.getMessage());
        }
    }



    public String registerUser() {
        Connection con = null;
        PreparedStatement ps = null;

        try {
            con = getConnection();
            userId = getNextUserid(con);
            ps = con.prepareStatement("insert into users values (?,?,?)");
            ps.setInt(1,userId);
            ps.setString(2,userName);
            ps.setString(3,password);
            ps.setString(4,email);
            ps.setString(5,address);
            ps.setString(6,phone);
            ps.executeUpdate();
            logged = true;
            return null;
        } catch (Exception ex) {
            return ex.getMessage();
        }
    }

    public boolean isLogged() {
        return logged;
    }

    public int getNextUserid(Connection con)  throws Exception
    {
        PreparedStatement ps = null;
        ps = con.prepareStatement("select nvl( max(userid),0) + 1 from users");
        ResultSet rs = ps.executeQuery();
        rs.next();
        int nextuserid = rs.getInt(1);
        rs.close();

        return  nextuserid;

    }

}

我的输出逻辑与logedIn布尔表达式有关。我在index.jsp文件中创建了输出表达式（如果要从数据库登录的用户名和密码正确，则应该连接），但输出总是输出为“否”，我的数据库连接就可以了。

输出是我的JSP文件中的Setup：

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    
</head>
<body bgcolor="beige">
<div style="text-align: center;">

    <jsp:useBean id="user" class="obs.User" scope="session" />

    <jsp:setProperty  name="user" property="*" />

    <%
        user.login();
        if (!user.isLogged()){
               out.print("No");
        } else{
           out.print("yes");}
    %>
    <h3>Invalid Login. Click <a href=index.html>here</a> to try again! </h3>




</div>
</body>
</html>

Finally this is my index.html :

    <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>


<body bgcolor="beige">

<h2>New User Registration </h2>
<hr>
<form action="register.jsp" method="post">
    <table>
        <tr>
            <td>
                User Name
            <td>
                <input type=text name=uname size=20>*
        </tr>
        <tr>
            <td>
                Password
            <td>
                <input type=password name=pwd size=20>*
        </tr>
        <tr>
            <td>
                Confirm Password
            <td>
                <input type=password name=pwd2 size=20>*
        </tr>

        <tr>
            <td>
                Email Address
            <td>
                <input type=text name=email size=30>*
        </tr>

        <tr>
            <td>Mailing Address
            <td>
                <textarea name="address" rows=3 cols=30></textarea>*
            </td>
        </tr>


        <tr>
            <td>
                Phone Number
            <td>
                <input type=text  name=phone  size=30>
        </tr>

    </table>
    <p>

        <input type=submit value="Register">
        <input type=reset value="Clear All">
    <p>
        <a href="login.html">Go Back</a>
</form>

</center>
</body>
</html>

我也将它作为依赖项添加到了pom.xml文件中：

<dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.21</version>
    </dependency>

请检查一下为什么输出为“否”的逻辑，并且看起来正确，请在此平台上发布此问题以征求意见，或者我的逻辑是否错误。另外，如果我的getConnection代码错误或要更改mysql连接器，请先谢谢。

Intellij：将我的getConnection代码链接到MySQL数据库Web应用程序J2EE时出现问题

如何解决Intellij：将我的getConnection代码链接到MySQL数据库Web应用程序J2EE时出现问题

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