为什么查询结果没有输出？

麻烦高手们帮忙看一下，为什么这个程序只能输出查询到的条数，但是输出不了查询结果啊？
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <%
        try{
        String driverName="com.mysql.jdbc.Driver";//驱动程序名
String userName="javaee";//数据库用户名
String userPasswd="123456";//密码
String dbName="drug";//数据库名
String tableName="clean_drug_like12";//表名
String url="jdbc:mysql://202.201.14.241/"+dbName+"?user="+userName+"&password="+userPasswd;//连结字符串
        Connection connection;
        Statement statement;
        int RowCount;
        Class.forName(driverName).newInstance();
connection=DriverManager.getConnection(url);
        statement = connection.createStatement();
        ResultSet rs=null;
        String sql="select count(*) from clean_drug_like12";
        String sql1="select * from clean_drug_like12 limit 1,10";
        rs=statement.executeQuery(sql);
        rs.next();
        RowCount=rs.getInt(1);
        out.println(RowCount);
        rs=statement.executeQuery(sql1);
        out.println(rs.getInt("ID"));
        out.println(rs.getDouble("XLogP"));
        }catch(Exception e){
                System.out.println("Exception:"+e.getMessage());
            }
        %>
    </body>
</html>
非常感谢！

解决方案 »

  1.   


            RowCount=rs.getInt(1); 
            out.println(RowCount); 
            rs=statement.executeQuery(sql1); 
            while(rs.next()){//使用循环打印出来，上面你懂得用rs.next()，为什么这里没有用呢？
               out.println(rs.getInt("ID")); 
               out.println(rs.getDouble("XLogP")); 
            }
      

  2.   

    如果就一条的话
    在rs=statement.executeQuery(sql1);
    加上rs.next();
      

  3.   

    如果连接数据库没错
    看看这里
     while(rs.next()){
               out.println(rs.getInt("ID")); 
            }
      

  4.   

    rs=statement.executeQuery(sql1); //重置了rs，下面必须要用rs.next才能到游标的第一行。
            out.println(rs.getInt("ID"));
            out.println(rs.getDouble("XLogP")); 
      

  5.   

    这时rs结果集的游标还在第一行的前面，必须rs.next()才会到达第一行，所以楼主这样当然取不到值了。
    一般返回多个结果时都用while(rs.next())，即判断又往前移。
      

  6.   

    谢谢大家！能不能再帮我看看这个是怎么回事？数据库里的记录很多，所以只能分页查询，一次查10条
        <body>
            <%
            try{
                String driverName="com.mysql.jdbc.Driver";//驱动程序名
                String userName="javaee";//数据库用户名
                String userPasswd="123456";//密码
                String dbName="drug";//数据库名
                String tableName="clean_drug_like12";//表名
                String url="jdbc:mysql://202.201.14.241/"+dbName+"?user="+userName+"&password="+userPasswd;//连结字符串
                Connection connection;
                Statement statement;
                int RowCount;
                Class.forName(driverName).newInstance();
                connection=DriverManager.getConnection(url);
                statement = connection.createStatement();
                ResultSet rs=null;
                int p,m,n;
                int PageSize=10;
                int ShowPage=1;
                int PageCount;
                int flag=0;      //标志位 查询是否都为空？
                int flag2=0;     //标志位 查询是否为第一个条件？
                int i=1;
                String sql="select * from clean_drug_like12";
                String sql1="";
                String sql2="select count(*) from clean_drug_like12";
                String sql3="";
                String search_txt_id="";
                String search_txt_XLogP1="";
                String search_txt_XLogP2="";
                String search_txt_bonds1="";
                String search_txt_bonds2="";
                String ToPage=request.getParameter("ToPage");
                if(request.getParameter("search_txt_id")!=null&&!request.getParameter("search_txt_id").equals("")){
                    search_txt_id=new String(request.getParameter("search_txt_id").trim().getBytes("8859_1"));
                }
                if(request.getParameter("search_txt_XLogP1")!=null&&!request.getParameter("search_txt_XLogP1").equals("")){
                    flag=1;
                    search_txt_XLogP1=new String(request.getParameter("search_txt_XLogP1").trim().getBytes("8859_1"));
                }
                if(request.getParameter("search_txt_XLogP2")!=null&&!request.getParameter("search_txt_XLogP2").equals("")){
                    flag=1;
                    search_txt_XLogP2=new String(request.getParameter("search_txt_XLogP2").trim().getBytes("8859_1"));
                }
                if(request.getParameter("search_txt_bonds1")!=null&&!request.getParameter("search_txt_bonds1").equals("")){
                    flag=1;
                    search_txt_bonds1=new String(request.getParameter("search_txt_bonds1").trim().getBytes("8859_1"));
                }
                if(request.getParameter("search_txt_bonds2")!=null&&!request.getParameter("search_txt_bonds2").equals("")){
                    flag=1;
                    search_txt_bonds2=new String(request.getParameter("search_txt_bonds2").trim().getBytes("8859_1"));
                }            if(search_txt_id!=null&&!search_txt_id.equals("")){
                    sql1=" where id="+search_txt_id;
                    sql3=" where id="+search_txt_id;
                }
                else if(flag==1){
                    if(search_txt_XLogP1!=null&&!search_txt_XLogP1.equals("")){
                        sql1=" where XLogP>="+search_txt_XLogP1;
                        flag2=1;
                    }
                    if(search_txt_XLogP2!=null&&!search_txt_XLogP2.equals("")){
                        if(flag2==1)
                            sql1=sql1+" and XLogP<="+search_txt_XLogP2;
                        else
                            {
                                sql1=" where XLogP<="+search_txt_XLogP1;
                                flag2=1;
                            }
                    }
                    if(search_txt_bonds1!=null&&!search_txt_bonds1.equals("")){
                        if(flag2==1)
                            sql1=sql1+" and RotatableBonds>="+search_txt_bonds1;
                        else{
                            sql1=" where RotatableBonds>="+search_txt_bonds1;
                            flag2=1;
                        }
                    }
                    sql3=sql1;
                }
                sql3=sql2+sql3;
                rs=statement.executeQuery(sql3);
                rs.next();
                RowCount=rs.getInt(1);
                PageCount=(RowCount+9)/10;
            %>
            <center>
                <table border="0">
                <tr>
                    <td>
                        <font size="6">查询结果</font>                </td>
                </tr>
                <tr>
                    <td>                     以下是搜索到的所有信息：
                         &nbsp;共：
                         <FONT color="blue">
                             <%=RowCount%>
                         </FONT>
                         条&nbsp;共
                         <FONT COLOR="blue">
                             <%=PageCount%>
                         </FONT>
                         页&nbsp;当前页为第
                         <FONT color="red">
                             <%=ShowPage%>
                         </FONT>
                          页
                          <%
                          if(PageCount>1){
                            if(ShowPage-3>0){
                                m=ShowPage-3;
                            }
                            else{
                                m=1;
                            }
                            if(ShowPage+3<PageCount){
                                n=ShowPage+3;
                            }
                            else{
                                n=PageCount;
                            }
                            %>                      转到页码：[
                          <%
                          for(p=m;p<=n;p++){
                            if(ShowPage==p){
                          %>                        <font color="red"><b><%=p%></b></font>
                            <%
                            }
                            else{
                            %>
                            <a
                            <%
                            if(ShowPage==p){
                            %>
                                style="color:red"
                                <%
                            }
                            %>
                            href="index.jsp?ToPage=<%=p%>&i=<%=p+(p-1)*9%>&search_txt_id=<%=search_txt_id%>&search_txt_XLogP1=<%=search_txt_XLogP1%>&search_txt_XLogP2=<%=search_txt_XLogP2%>search_txt_bonds1=<%=search_txt_bonds1%>search_txt_bonds2=<%=search_txt_bonds2%>">
                                <%=p%>
                            </a>
                            <%
                            }
                  }
                            %>
                            ]
                            <%
                            }
                %>
                    </td>
                </tr>
                </table>
                <table border="1" width="800">
                    <tr>
                        <td width="150" align="center">ID</td>
                        <td width="200" align="center">INFORMATION</td>
                    </tr>
                     <%
                    sql1=sql+sql1+"limit "+i+"10";
                    rs=statement.executeQuery(sql1);       
                while(rs.next()){
                out.println("<tr align=center>");
                out.println("<td align=center width=150 rowspan=2>"+rs.getInt("ID")+"</td>");
                out.println("<td align=center width=150>"+"XLogP="+rs.getDouble("XLogP")+"</td>");
                out.println("</tr>");
                out.println("<tr>");
                out.println("<td align=center width=200>"+"RotatableBonds="+rs.getInt("RotatableBonds"));
                out.println("</td>");
                out.println("</tr>");
                out.println("</tr>");
            }
            %>
             </table>
                <TABLE BORDER="0" WIDTH="700">
                    <tr valign="baseline" align="center">
                        <td width="500">
                            &nbsp;
                        </td>
                        <%
                        if(ShowPage!=1){
                        %>                        <td width="50">
                                <a href="index.jsp?ToPage=<%=ShowPage-1%>&i=<%=i-10%>&search_txt_id=<%=search_txt_id%>&search_txt_XLogP1=<%=search_txt_XLogP1%>&search_txt_XLogP2=<%=search_txt_XLogP2%>search_txt_bonds1=<%=search_txt_bonds1%>search_txt_bonds2=<%=search_txt_bonds2%>">
                                    上一页
                                </a>
                            </td>
                            <%
                            }
                if(ShowPage!=PageCount){
                    %>
                    <td width="50">
                        <a href="index.jsp?ToPage=<%=ShowPage+1%>&i=<%=i+10%>&search_txt_id=<%=search_txt_id%>&search_txt_XLogP1=<%=search_txt_XLogP1%>&search_txt_XLogP2=<%=search_txt_XLogP2%>search_txt_bonds1=<%=search_txt_bonds1%>search_txt_bonds2=<%=search_txt_bonds2%>">
                            下一页
                        </a>
                    </td>
                    <%
                    }
                %>
                    </tr>
                </TABLE>
                    <%            rs.close();
                statement.close();
                connection.close();
                sql1="";
                sql3="";
                }catch(Exception e){
                    System.out.println("Exception:"+e.getMessage());
                }
                    %>
                </center>
        </body>
      

  7.   

    程序有点长了，呵呵，还有一个问题，从第一页超链接转到第二页以后就什么都不显示了，我JAVA学的不好，麻烦大家给看看啊！
      

  8.   

    晕了   好像是Struts1.X的；  
      

  9.   


    太长了没法看，但你的sql应该会有问题，看见很多没有加空格的，另外你的sql拼来拼去的话。初始化可以这样：
    String sql = "select * from tble where 1=1 ";
    现在再加入其他条件就直接
    if(***不空）{
    sql += " and **=** "; //双引号前后加空格。
    }另外就是拼好的sql在执行之前，最好吧sql 打印出来放数据库里面去执行看看对不对。