Question

大家好我在bootstrap中设计了注册表单，我使用远程验证器验证了所有表单文件，我有registerdao.java方法，它有checkusername布尔方法检查所有行，如果用户名存在，则返回用户名字符串，否则为false我在registartiion servlet中有checkusernameexists方法，当你输入用户名字段时检查用户名。我不明白为什么我的代码没有显示任何东西。下面是代码没有检查用户名对数据库和通知。如何编写javascript以便它检查用户名对数据或给我一些想法如何使这段代码工作？任何帮助都会有很大的帮助吗？谢谢

ReegisterDao.java public static boolean checkUserName（String userName）throws SQLException { String checkUserNameQuery =“select * from EmployeeDetails USER_NAME ='”+ userName +“'”;

  try{


 // preparing some objects for connection
currentCon = ConnectionManager.getConnection();
Statement stmt = currentCon.createStatement();
rs  = stmt.executeQuery(checkUserNameQuery);
boolean more = rs.next();

    // if user does not exist set the isValid variable to false
    return more;
     }



catch (InstantiationException | IllegalAccessException e){}

返回false; }

RegistrationServlet.java

public int checkUserNameExists(RegistrationBean user) throws SQLException{

        int a=RegistrationDao.Register(user);


    return a;

}

这是验证用户名

的远程验证器的一部分

   username: {
                    validators: {
                        notEmpty: {
                            message: 'The username is required'
                        },
                        stringLength: {
                            min: 6,
                            max: 30,
                            message: 'The username must be more than 6 and less than 30 characters long'
                        },
                        regexp: {
                            regexp: /^[a-zA-Z0-9_\.]+$/,
                            message: 'The username can only consist of alphabetical, number, dot and underscore'
                        },
                        remote:{
                            message:'This Username is already taken',
                            url:'https://localhost:8080/RegistrationServlet.java',
                            data:'username'
                        },
                        type:'POST'


                }   

                },

这是bootstrap用户名字段

的一部分

<div class="form-group">
    <label class="col-xs-2 control-label">Username</label>

    <div class="col-xs-4">
        <input type="text" class="form-control" name="username" placeholder="Username" />
    </div></div>

Answer 1

返回类型必须是有效的json格式。我认为从servlet返回到验证代码的任何东西都不是正确的json形式。使用inspect元素并在网络标签中查看它正在返回的内容。

首先你必须将你的遥控器更改为喜欢这个

             remote: {
                        type: "POST",
                        url: 'RegistrationEmailCheck',//servlet
                        delay: 1000,

                        message: 'Your Message'
                    }

并从servlet返回这样的数据

  public class RegistrationEmailCheck extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    response.setContentType("application/json");

  PrintWriter out = response.getWriter();
JSONObject json = new JSONObject();
String availEmail = request.getParameter("email");
System.out.println(availEmail);
String SQL = "SELECT email FROM login WHERE email='" + availEmail + "'";
Connection con = DBInfo.getConn();
Statement st;
ResultSet rs;

try {
    st = con.createStatement();
    rs = st.executeQuery(SQL);


    if (rs.next()) {

        out.print("{\"valid\" : false }");
        json.put("valid", false);
        System.out.println("false");


    } else {

        out.print("{\"valid\" : true }");
        json.put("valid", true);
        System.out.println("true");


    }


} catch (Exception ex) {
    ex.printStackTrace();
} finally {

    out.close();
    }



}


}

此代码用于检查电子邮件

使用java bean和jquery远程验证器进行即时用户名检查

1 个答案: