Javascript 如何修复登录到Ajax成员时出现的会话错误？-弹簧MVC2_Javascript_Java_Jquery_Ajax_Spring Mvc

Javascript 如何修复登录到Ajax成员时出现的会话错误？-弹簧MVC2

javascript java jquery ajax spring-mvc

Javascript 如何修复登录到Ajax成员时出现的会话错误？-弹簧MVC2,javascript,java,jquery,ajax,spring-mvc,Javascript,Java,Jquery,Ajax,Spring Mvc,MemberService.java： public HashMap<String, Object> login(String id,String pw) { HashMap<String, Object> result = memberDao.selectOne(id); if(result != null) // 존재하는 값이 있으면 { String opwd = (String) result.get("pw"); //

MemberService.java：

public HashMap<String, Object> login(String id,String pw)
{
    HashMap<String, Object> result = memberDao.selectOne(id);

    if(result != null) // 존재하는 값이 있으면
    {
        String opwd = (String) result.get("pw"); // opwd = 존재하는값의 pw값을 가져온 값

        if(opwd.equals(pw)) 
        {
            return result; // true면 존재하는값을 반환
        }
        else
        {
            return null;
            //return null; // 아니면 값을 반환하지 않음.
        }
    }
    else // 존재하는 값이 없다면
    {
        return null;
    }
}

因此，该项目表现良好。但代码似乎效率低下

修改前出现错误的原因是我认为如果它不在HashMap中，它将返回一个空值

我现在有三个问题

我想知道我认为的问题是否正确

如何才能更有效地编写代码

您应该如何处理MemberService中的异常处理

如果您的代码运行良好，并且您只关心如何改进它，您应该将其发布到。我在那里发布了一个问题。谢谢@nisargshah如果您的代码运行良好，并且您只关心如何改进它，您应该将其发布到。我在那里发布了一个问题。谢谢你@NisargShah

@RequestMapping("loginOK.do")
@ResponseBody
public String login(@RequestParam(required=false) String id, @RequestParam(required=false) String pw,HttpSession session, HttpServletRequest request, HttpServletResponse response) throws IOException 
{
    HashMap<String, Object> loginIdentify = mService.login(id,pw);
    System.out.println("loginIdentify is that :  " + loginIdentify);

    session.setAttribute("id", loginIdentify.get("id"));

    if(loginIdentify == null)
    {
        return "0"; // member isn't exist
    }
    else
    {
        return "1"; // member is exist
    }
}

<%@ page language="java" contentType="text/html; charset=EUC-KR"
    pageEncoding="EUC-KR"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=EUC-KR">
<link rel="stylesheet" href="css/normalize.css">
<link rel="stylesheet" href="css/swiper.min.css">
<link rel="stylesheet" href="css/loginPage.css">
<script type="text/javascript" src="js/jquery-3.1.1.min.js"></script>
<script type="text/javascript" src="js/swiper.jquery.min.js"></script>
<title>Insert title here</title>
</head>
<body>
<jsp:include page="header.jsp" />
<div class="loginPage_main">
    <div class="pageName">
        <img class="pageName_image" src="images/greeting_title.jpg">
        <div class="pageName_explanation">
            <p>로그인</p>
        </div>
    </div>
    <div class="location">
    </div>
    <div class="loginForm_area">
        <div class="hidden_area">
            <div class="img_lock_area">
                <img src="images/lock.png" class="img_lock">
            </div>
            <form action="loginOK.do" id="login_frm" name="frm" method="post" onsubmit="return checkValue()">
                <div class="input_zone">
                    <div class="input_id">
                        <span>&nbsp;&nbsp;ID</span><input type="text" placeholder="아이디를 입력하세요" style="width:280px;margin-left: 10px;" name="id">
                    </div>  
                    <div class="input_pw">
                        <span>PW</span><input type="password" placeholder="비밀번호를 입력하세요" style="width:280px;margin-left: 10px;" name="pw">
                    </div>
                </div>
            </form>     
                <div class="loginBtn" onclick="document.getElementById('login_frm').onsubmit();">
                    <div style="margin-top: 22px;">
                        <span class="loginOK">Login</span>
                    </div>
                </div>
        </div>
        <div class="loginForm_subBtn_area">
            <div class="btn_value_join">
                <a class="btn_join" onclick="location.href='move_joinMemberPage.do'">회원가입</a>
            </div>
            <div class="btn_value_find_id">
                <a class="btn_find_id">아이디 찾기</a>
            </div>
            <div class="btn_value_find_pw">
                <a class="btn_find_pw">비밀번호 찾기</a>
            </div>
        </div>
    </div>
</div>
<script type="text/javascript">

    function checkValue() 
    {
        var form = document.frm;
        var id = form.id.value;
        var pw = form.pw.value;

        if(!form.id.value || !form.pw.value)
        {
            alert('아이디 혹은 비밀번호를 입력하세요.');
            return false;
        }

        $.ajax
        ({
            type: 'POST',
            url: 'loginOK.do',
            dataType:"text",
            data:{"id":id,"pw":pw},
            success: function(data)
            {
                if(data == 1)
                {
                    window.location.href='main.do';
                }
                else
                {
                    alert('아이디 혹은 비밀번호를 확인하세요.');
                }
            },
            error: function()
            {
                alert('error');
            }
        })
    }       
</script>
</body>
</html>

if(loginIdentify == null)
{
    return "0"; // member isn't exist
}
else
{
    session.setAttribute("id", loginIdentify.get("id"));
    return "1"; // member is exist
}