Question

将输入用户名和密码 ans将其传递给validation.jsp

的login.jsp

<center>
            <table border="1" cellpadding="5" cellspacing="2">
                <thead>
                    <tr>
                        <th colspan="2">Login Here</th>
                    </tr>
                </thead>
                <tbody>
                    <tr>
                        <td>Username</td>
                        <td><input type="text" name="username" required/></td>
                    </tr>
                    <tr>
                        <td>Password</td>
                        <td><input type="password" name="password" required/></td>
                    </tr>
                    <tr>
                        <td colspan="2" align="center"><input type="submit" value="Login" />
                            &nbsp;&nbsp;
                            <input type="reset" value="Reset" />
                        </td>                        
                    </tr>                    
                </tbody>
            </table>
            </center>
        </form>
    </body>
</html>

validation.jsp
它将验证数据库中的数据并返回;

<%@ page import ="java.sql.*" %>
<%
    try{
        String username = request.getParameter("username");   
        String password = request.getParameter("password");
        Class.forName("com.mysql.jdbc.Driver");  // MySQL database connection
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/tejas?" + "user=root&password=tejas");    
        PreparedStatement pst = conn.prepareStatement("Select user,pass from login where user=tejas and pass=te65");
        pst.setString(1, username);
        pst.setString(2, password);
        ResultSet rs = pst.executeQuery();                        
        if(rs.next())           
           out.println("Valid login credentials");        
        else
           out.println("Invalid login credentials");            
   }
   catch(Exception e){       
       out.println("Something went wrong !! Please try again");       
   }      
%>`

这是两个保存在webapps文件夹下的代码 webapps文件夹包含web-inf login.jsp validation.jsp

的web.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
version="3.1"
metadata-complete="true">
<display-name>Welcome to Tomcat</display-name>
<description>
Welcome to Tomcat
</description>
</web-app>

我需要向web.xml添加内容吗？请帮忙......

Answer 1

<强>第一
您setString在查询中没有任何?，您必须使用，所以如果您想要一些动态，则必须使用：

 pst = conn.prepareStatement("Select user,pass from login where user=? and pass=?");
 //------------------------------------------------------------------^----------^
 pst.setString(1, username);
 pst.setString(2, password);

如果您想修改用户名和密码，则无需使用.setString。

运行jsp后，请求的错误源不可用

1 个答案: