0 
String name = request.getParameter("type");
String queryString = "SELECT * FROM Customer WHERE TYPE='Provider';";

rs = statement.executeQuery(queryString);
while(rs.next()) out.print(rs.getString(2));

何も印刷しません、なぜですか？DB接続を確認しましたが、正常に接続されています。何が問題なのでしょう？

jspのコード全体。コード全体に問題があると思います。ここでの問題は何ですか？

<%@page import="java.sql.Statement"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.DriverManager"%>
<%@page import="java.sql.Connection"%>
<head> 
        <meta charset="utf-8">

        <title>GET CUSTOMER LIST</title><meta name="keywords" content="contact, direction,"><meta name="description" content="">

        <meta name="HandheldFriendly" content="True">
        <meta name="MobileOptimized" content="320">
        <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">



        <meta name="format-detection" content="telephone=no"> 
        <meta name="format-detection" content="address=no">  

        <link rel="canonical" href="#">

        <link rel="apple-touch-icon-precomposed" sizes="114x114" href="http://www.onbile.com/nbproject/private/sushi/media/icon/apple-touch-icon.png">
        <link rel="apple-touch-icon-precomposed" sizes="72x72" href="http://www.onbile.com/nbproject/private/sushi/media/icon/apple-touch-icon.png">
        <link rel="apple-touch-icon-precomposed" href="http://www.onbile.com/nbproject/private/sushi/media/icon/apple-touch-icon-precomposed.png">
        <link rel="shortcut icon" href="http://www.onbile.com/nbproject/private/sushi/media/icon/apple-touch-icon.png">

        <!-- Mobile IE ows us to activate ClearType technology for smoothing fonts for easy reading -->
        <meta http-equiv="cleartype" content="on">

                <link rel="shortcut icon" href="http://www.onbile.com/favicon.ico">     
        <style type="text/css" media="screen">
            /*reset*/
            html, body { margin: 0; padding: 0; border: 0; }
            body { font-family:Helvetica, Arial, sans-serif; line-height:1.5; font-size:16px; background: #fff; color: #333; word-wrap: break-word; -webkit-text-size-adjust: none; }
            h1, h2, h3, h4, h5, h6{ font-weight: normal; margin: 0;}
            p img { float: left; margin: 0 10px 5px 0; padding: 0; }
            img { border: 0; max-width: 100%; }
            table { width:auto; border-collapse: collapse;border-spacing: 0; }
            article, aside, details, figcaption, figure, footer, header, hgroup, nav, section { display: block; }

            /*Non-semantic helper classes*/
            .ir { display: block; border: 0; text-indent: -999em; overflow: hidden; background-color: transparent; background-repeat: no-repeat; text-align: left; direction: ltr; }
            .ir br { display: none; }

            @font-face {
                font-family: 'FagoCoRegular';
                src: url('http://www.onbile.com/nbproject/private/sushi/media/font/fagoco-webfont.eot');
                src: url('http://www.onbile.com/nbproject/private/sushi/media/font/fagoco-webfont.eot?#iefix') format('embedded-opentype'),
                     url('http://www.onbile.com/nbproject/private/sushi/media/font/fagoco-webfont.woff') format('woff'),
                     url('http://www.onbile.com/nbproject/private/sushi/media/font/fagoco-webfont.ttf') format('truetype'),
                     url('http://www.onbile.com/nbproject/private/sushi/media/font/fagoco-webfont.svg#') format('svg');
                font-weight: normal;
                font-style: normal;
            }
            @font-face {
                font-family: 'FagoCoBlackRegular';
                src: url('http://www.onbile.com/nbproject/private/sushi/media/font/fagoco-black-webfont.eot');
                src: url('http://www.onbile.com/nbproject/private/sushi/media/font/fagoco-black-webfont.eot?#iefix') format('embedded-opentype'),
                     url('http://www.onbile.com/nbproject/private/sushi/media/font/fagoco-black-webfont.woff') format('woff'),
                     url('http://www.onbile.com/nbproject/private/sushi/media/font/fagoco-black-webfont.ttf') format('truetype'),
                     url('http://www.onbile.com/nbproject/private/sushi/media/font/fagoco-black-webfont.svg#FagoCoBlackRegular') format('svg');
                font-weight: normal;
                font-style: normal;
            }

            body {
                font-family: 'FagoCoRegular';
            }
            h2.title1 {
                padding: 22px 15px 20px 15px;
                line-height: 0.9em;
            }
            .title2 {
                line-height: 0.9em;
            }
            .title4 {
                letter-spacing: -0.05em;
                line-height: 1.2em;
            }
            img.image {
                padding: 1px 0;
                display: block;
                width: 100%;
            }
            .imgcontent {
                position: relative;
                overflow: hidden;
                border-top-width: 1px;
                border-top-style: solid;
                border-bottom-width: 1px;
                border-bottom-style: solid;
            }
            img.image.left {
                float: left;
            }
            img.image.right {
                float: right;
            }
            img.image.center {
                margin: 0 auto;
            }
            .order {
                margin-bottom: 1px;
                border-bottom-style: solid;
                border-bottom-width: 1px;
                display: block;
                padding: 4px;
            }
        </style>

        <link rel="stylesheet" href="http://www.onbile.com/assets/websites/final/052/333/052333/css/52333_f.css"><link rel="stylesheet" href="http://www.onbile.com/assets/websites/final/052/333/052333/css/52333_c.css">      
        <!--[if gte IE 8.0]>
        <style type="text/css">
            .t-sushi-p-gallery-content .list-items li {
                width: 46%;
            }
        </style>
        <![endif]-->


        <script src="http://www.onbile.com/nbproject/private/sushi//js/modernizr.custom.09105.js"></script>


    </head> 

    <body>

        <div id="container">



        <header class="t-sushi-p-header int">
            <div class="header">
                <span class="adorn"></span>
                <a href="http://tekirmobile.onbile.com/" class="btn back ir">back</a>
                <h1 class=""><a href="http://tekirmobile.onbile.com/" id="logotype"><img src="http://www.onbile.com/assets/websites/final/052/333/052333/smooth_logo.png" class=" center" style="width:60%;"></a></h1>              <a href="#" class="btn menu ir">menu</a>
                <a href="#container" class="btn menu ir on">menu</a>
            </div>
        </header>




    <header class="t-sushi-p-subtitle">
        <p title="My own profile" class="subtitle edit_element" id="1688529_subtitle" type="text">My own profile</p>
    </header>




        <style>
            #container:target nav.t-sushi-p-menu.acor ul {
                height: 160px;
            }
        </style>
        <nav class="t-sushi-p-menu acor">
            <ul>
                <li class="selected"><a href="http://127.0.0.1/getCustomerList.html" class="menu">GET CUSTOMER LIST</a></li><li class=""><a href="http://tekirmobile.onbile.com//about-me" class="menu">MONITOR CASH FLOW</a></li><li class=""><a href="http://tekirmobile.onbile.com//curriculum-vitae" class="menu">GET CUSTOMER STATE INFO</a></li><li class=""><a href="http://tekirmobile.onbile.com//photo-gallery" class="menu">MONITOR FINANCIAL TRANSACTIONS</a></li><li class=""><a href="http://tekirmobile.onbile.com//blog" class="menu">GET PAYMENT PLAN</a></li>         </ul>
        </nav>











    <div class="t-sushi-p-contact-content">
        <!-- <h2 title="Contact with Mike Stain" class="title1 edit_element" id='1688531_titles' type='text'>Contact with Mike Stain</h2> -->
        <h2 class="title1">GET CUSTOMER LIST</h2>
<form name="input" action="/TekirMobile/getCustomerList" method="post">
        <table>
<div class="prop">



<span class="value "><select name="type" class="middle" size="1">   <option value="All">All</option>
    <option value="Customer" selected="selected">Customer</option>
    <option value="Provider">Provider</option>
    <option value="Bank">Bank</option>
    <option value="Foundation">Foundation</option>
    <option value="Agent">Agent</option>
    <option value="Branch">Branch</option>
    <option value="Contact">Contact</option>
    <option value="Related">Related</option>
    <option value="Personnel">Personnel</option>
</select>
        </span>
    </div>

</table>
<br />
<input type="submit" value="Search" name="submit">


 <% 




try {
/* Create string of connection url within specified format with machine name, 
port number and database name. Here machine name id localhost and 
database name is usermaster. */ 
String connectionURL = "jdbc:mysql://localhost:3306/TekirMobile"; 

// declare a connection by using Connection interface 
Connection connection = null; 

// Load JBBC driver "com.mysql.jdbc.Driver" 
Class.forName("com.mysql.jdbc.Driver").newInstance(); 

/* Create a connection by using getConnection() method that takes parameters of 
string type connection url, user name and password to connect to database. */ 
connection = DriverManager.getConnection(connectionURL, "root", "fenderpass");

 ResultSet rs = null;
 Statement statement = null;


if(request.getParameter("submit")!=null)
 {


String name = request.getParameter("type");
String queryString = "SELECT * FROM Customer WHERE TYPE='Provider'";

out.print(queryString);


rs = statement.executeQuery(queryString);
 for (int i = 1; rs.next(); i++) { 
    out.println("row=" + i + ": " + rs.getString(2));
} 


}

// check weather connection is established or not by isClosed() method 
if(!connection.isClosed())
%>
<font size="+3" color="green"></b>
<% 
connection.close();
}
catch(Exception ex){

%>
</font>
<font size="+3" color="red"></b>
<%
}
%>

</form>








                </div>


    </div>




    <footer class="t-sushi-p-footer">

        <h5 title="" class="title5 edit_element" id="1688532_title_contact" type="text"></h5>
        <div class="small edit_element" id="1688532_contact_description" type="textarea"><p>©2012 | License | Privacy | Özgür Yaz?l?m&nbsp;</p></div>
    </footer>





    <div class="t-sushi-p-social">
        <ul class="social">

            <li class="facebook" id="facebook_elem"> 
                    <a href="http://www.facebook.com/" class="" target="_blank">Facebook</a>
                   </li><li class="twitter" id="twitter_elem"> 
                    <a href="http://www.twitter.com/" class="" target="_blank">Twitter</a>
                   </li><li class="linkedin" style="display:none" id="linkedin_elem"> 
                    <a href="http://www.linkedin.com/" class="" target="_blank">Your Linkedin</a>
                   </li><li class="skype" style="display:none" id="skype_elem"> 
                    <a href="http://www.skype.com/" class="" target="_blank">Your Skype</a>
                   </li><li class="flickr" style="display:none" id="flickr_elem"> 
                    <a href="http://www.flickr.com/" class="" target="_blank">Your Flickr</a>
                   </li><li class="youtube" style="display:none" id="youtube_elem"> 
                    <a href="http://www.youtube.com/" class="" target="_blank">Your Youtube</a>
                   </li><li class="google" style="display:none" id="google_elem"> 
                    <a href="http://www.google.com/" class="" target="_blank">Your Google</a>
                   </li><li class="email" style="display:none" id="email_elem"> 
                    <a href="mailto:" class="" target="_blank"></a>
                   </li>            
        </ul>
    </div>

        </div> <!--! end of #container -->


                        <div style="height:51px;width:100%;clear:both">&nbsp;<br></div>  
                        <div style="position:fixed; bottom:0px;margin-left:auto;margin-right:auto">
                    <!--qzkqc-->
</div>

                        </div>
                    </body>
4

2 に答える 2

5

おそらく、結果が返されないためです。

于 2012-12-26T20:02:49.060 に答える
1

私が試みるいくつかのこと：

クエリの最後にあるセミコロンを削除します。ステートメントに渡されるSQLクエリには、終了セミコロンは必要ありません。

表示される最後の行をに変更します

for (int i = 1; rs.next(); i++) { 
    out.println("row=" + i + ": " + rs.getString(2));
}

このようにして、返された行がまったくなかったかどうか、または返されたすべての行が空の文字列であったかどうかを判断できます。

ステートメントが初期化されることはありません。ステートメントを使用しようとすると、NullPointerExceptionが発生します。キャッチブロックに痕跡がないまま食べられたために表示されていない例外がスローされた可能性があります。次のように、catchブロックを編集して、例外からのスタックトレースを表示します。

}
catch(Exception ex){
    ex.printStackTrace();
}
于 2012-12-26T20:04:53.433 に答える