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用第归树型展现BBS数据库 出错了,小第正对你仰望和期待中......

(哥们儿们啊能不能帮我举个例子啊,一个用树型结构展现BBS数据库数据的例子,包括数据库的定义和程序的实现!那样的话我感激不尽了)
我做的是出错了,刚开始虽然有些小问题但还能运行。但最后有不行了,直到我调试得再也没有办法了!具体如下:
最好能给我一个BBS数据库树形展现的简单例子,包括数据库定义,和算法的实现(跪下了)
定义的mysql数据库
 

<%--
    Document   : index
    Created on : 2008-9-26, 11:29:31
    Author     : caobaoshusheng
--%>
<%@page contentType="text/html" pageEncoding="gbk"%>
<%@ page import ="java.lang.*"%>
<%@ page import = "java.sql.*"%>
<%!
    String pstring = "";

    private void tree(Connection conn, int id, int floor) {
        Statement stat = null;
        ResultSet rs = null;
        String ssql = "";
        String flstring = "";
        int i;
        for (i = 0; i < floor; i++) {
            flstring = flstring + "-----";
        }
        try {
            stat = conn.createStatement();
            ssql = "select * from BbsRecord where sid=" + id;
            while (rs.next()) {
                rs = stat.executeQuery(ssql);
                pstring = pstring + "<tr><td>" + rs.getInt("id") + "</td><td>" + flstring + rs.getString("title") + "</td><td>" +
                        "" + "</td><td>" + rs.getDate("time") + "</td></tr>";
                if (rs.getInt("leaf") == 0) {
                    tree(conn, rs.getInt("id"), floor + 1);
                }
            }
        } catch (SQLException e) {
            System.out.println(e.getMessage());
        } finally {
            try {
                rs.close();//提示是说这里有问题!
                stat.close();
                conn.close();
            } catch (SQLException e) {
                System.out.println("close erro!");
            }
        }
    }
%>
<%
            Class.forName("com.mysql.jdbc.Driver");
            String url ="jdbc:mysql://127.0.0.1:3306/test?user=root&password=159753";
            Connection conn = DriverManager.getConnection(url);
            tree(conn, 1, 0);
%>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=gbk">
        <title>BBS Mysql</title>
    </head>
    <body>
        <center>
            <table>
                <%= pstring%>
                <%pstring = "";%>
            </table>
        </center>
    </body>
</html>

错误报告:

HTTP Status 500 -


type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /index.jsp at line 36
33:             System.out.println(e.getMessage());
34:         } finally {
35:             try {
36:                 rs.close();
37:                 stat.close();
38:                 conn.close();
39:             } catch (SQLException e) {
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

 

root cause

java.lang.NullPointerException
org.apache.jsp.index_jsp.tree(index_jsp.java:39)
org.apache.jsp.index_jsp._jspService(index_jsp.java:100)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

 

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.16 logs.


Apache Tomcat/6.0.16

posted on 2008-09-28 12:32 草包书生 阅读(1043) 评论(4)  编辑  收藏

评论

# re: 用第归树型展现BBS数据库 出错了,小第正对你仰望和期待中......[未登录] 2008-09-28 13:41 vincent

re is null!  回复  更多评论   

# re: 用第归树型展现BBS数据库 出错了,小第正对你仰望和期待中......[未登录] 2008-09-28 13:41 vincent

rs is null  回复  更多评论   

# re: 用第归树型展现BBS数据库 出错了,小第正对你仰望和期待中......[未登录] 2008-09-28 13:42 vincent

while (rs.next()) and rs.close(), rs is null.  回复  更多评论   

# re: 用第归树型展现BBS数据库 出错了,小第正对你仰望和期待中...... 2008-09-28 17:46 草包书生

问题已解决,thanks for everyone~!  回复  更多评论   


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