Question

  <%@page language="java" contentType="text/html" import="java.sql.*" pageEncoding="UTF-8" %>
  <!DOCTYPE html>
 <html> 
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Register</title>
</head>
<body>
    <form> 
        <table width="300">
            <tr>
                <td>Enter User Name:<td><input type="text" name="uname">
            </tr>
            <tr>
                <td>Enter Password:
                <td><input type="password" name="pass"></td>
            </tr>
            <tr>
                <td><button  name="b1" >Save</button>
                <td><input type="reset" name="rs" value="Reset"></td>
        </table>
    </form> 

    <%
        Class.forName("com.mysql.jdbc.Driver");
        Connection con = DriverManager.getConnection("jdbc:mysql://localhost/projectjsp", "root", "");
        Statement s = con.createStatement();
        String a = request.getParameter("uname");
        String b = request.getParameter("pass");
        String q = "insert into userlogin (username,password) values ('" + a + "','" + b + "')";
        s.execute(q);
        out.print(q);

    %>  

</body>
</html>

在Web浏览器中打开它时会显示错误和异常

javax.servlet.ServletException：com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException：键'PRIMARY'的重复条目'null'

当代码被删除时，页面显示正常。

如何将给定的java代码放在按钮“b1”上。因此当按下它时代码运行

0 个答案: