Question

我正在开发一个网上银行应用程序，这是我陷入困境的一部分。

- ＆gt;用户会在HTML页面上显示一个表单，以输入其详细信息，以创建帐户。

- ＆gt;然后将详细信息输入MySQL数据库，并将用户重定向到JSP页面，在该页面中应显示他的帐号（使用MySQL自动增量功能自动生成）和秘密4位数pin（为每个用户随机生成，而不是自动递增）。

来自我的servlet的doPost（）方法的代码在DB中插入值并重定向到JSP就在这里 -

try {
Class.forName("com.mysql.jdbc.Driver");
Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/inb", "root", "root");

//The user's password has to be converted into a salted hash before storing in the database.
String hashed_password=CreateDigest.getPasswordDigest(request.getParameter("password"));

PreparedStatement ps=con.prepareStatement("insert into inb.users values (NULL, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)");
        ps.setString(1, request.getParameter("name1"));
        ps.setString(2, request.getParameter("name2"));
        ps.setString(3, request.getParameter("name3"));
        ps.setString(4, request.getParameter("dob"));
        ps.setInt(5, Integer.parseInt(request.getParameter("age")));
        ps.setString(6, request.getParameter("email"));
        ps.setString(7, request.getParameter("mobnum"));
        ps.setString(8, request.getParameter("address1"));
        ps.setString(9, request.getParameter("address2"));
        ps.setString(10, request.getParameter("pannum"));
        ps.setString(11, request.getParameter("aadhar"));
        ps.setString(12, hashed_password);
        ps.setString(13, request.getParameter("acc_bal"));
        ps.setInt(14, pin);

            int i=ps.executeUpdate();


    //Check if records have been actually been inserted or not.
        if (i>0)    {
            response.sendRedirect("AccountOpened.jsp");
        }

    } catch (ClassNotFoundException | SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

现在，这是显示帐户号的JSP代码。和用户的针脚 - （last_acc_no和last_pin是我的Servlet类中的静态变量，我创建它是为了保存最后插入的帐号no和pin。）

<% 
String acc_no=CreateAccount.last_acc_No;
int pin=CreateAccount.last_pin;
%>
<h3>Congratulations ! Your account has been created.</h3>.
<br/><br/>
Your Account Number Is : <b> <%= acc_no %> </b>
<br/><br/>
Your Secret PIN No. Is : <b> <%= pin %> </b>

现在，我想检索最后插入的用户的account_no和pin，以便我可以在JSP页面上显示它。我无法找到一种方法。

Answer 1

try {
Class.forName("com.mysql.jdbc.Driver");
Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/inb", "root", "root");

//The user's password has to be converted into a salted hash before storing in the database.
String hashed_password=CreateDigest.getPasswordDigest(request.getParameter("password"));

PreparedStatement ps=con.prepareStatement("insert into inb.users values (NULL, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)", , Statement.RETURN_GENERATED_KEYS);
        ps.setString(1, request.getParameter("name1"));
        ps.setString(2, request.getParameter("name2"));
        ps.setString(3, request.getParameter("name3"));
        ps.setString(4, request.getParameter("dob"));
        ps.setInt(5, Integer.parseInt(request.getParameter("age")));
        ps.setString(6, request.getParameter("email"));
        ps.setString(7, request.getParameter("mobnum"));
        ps.setString(8, request.getParameter("address1"));
        ps.setString(9, request.getParameter("address2"));
        ps.setString(10, request.getParameter("pannum"));
        ps.setString(11, request.getParameter("aadhar"));
        ps.setString(12, hashed_password);
        ps.setString(13, request.getParameter("acc_bal"));
        ps.setInt(14, pin);

            int i=ps.executeUpdate(); 


    //Check if records have been actually been inserted or not.
            ResultSet rs = ps.getGeneratedKeys();
            if(rs.next())
            {
                int id = rs.getInt(1);
            request.setAttribute("id", id);
            request.setAttribute("pin", pin);
            request.getRequestDispatcher("AccountOpened.jsp").forward(request, response);
        }

    } catch (ClassNotFoundException | SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

在你的jsp页面中：

<h3>Congratulations ! Your account has been created.</h3>.
<br/><br/>
Your Account Number Is : <b> <%= request.getAttribute("id")%> </b>
<br/><br/>
Your Secret PIN No. Is : <b> <%= request.getAttribute("pin") %> </b>

Answer 2

您是否考虑在Return SCOPE_IDENTITY()中使用t-sql？

int i是否会返回帐号 - 应该是。这样您就不必担心它是数据库中最顶层的条目。严格说你只想要创建的最后一条记录是危险的。用户A和用户B可以在同一时间创建帐户并获得纠结/交叉的帐户信息。一旦你拥有了“int i”的accountNumber，你就不会有从数据库中重新获取这些信息的问题吗？

这有帮助吗？

检索数据库中插入的最后一行

2 个答案: