关于JSP的一个问题:NullPointerException错误

11 楼

kingzhm [专家分：450] 发布于 2005-07-25 13:47:00

在有，这个程序写实在是有点……，不说了，别骂我

以后注意
注释
对齐方式
定义变量名称

12 楼

kingzhm [专家分：450] 发布于 2005-07-25 13:48:00

以后一定注意

定义变量名称
注释
对齐方式

13 楼

kingzhm [专家分：450] 发布于 2005-07-25 14:02:00

<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.lang.*, java.sql.* " %>
<html>

    <head>
        <title>录入成功</title>
    <head>

    <body>
        <form>
            <%
                Connection con = null;
                Statement stmt = null;
                ResultSet rs = null;
                //=======================执行数据库连结动作========================

                public void jspInit()
                {
                    try
                    {
                        Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); //载入驱动程式类别
                        con = DriverManager.getConnection("jdbcdbc:LocalServer"," "," "); //建立数据库连线
                        //建立Statement变量, 并设定记录指标类型为可前後移动
                        stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                        ResultSet.CONCUR_READ_ONLY);
                    }catch(Exception ex)
                    {
                        System.out.println(ex.toString());
                    }
                }

                //==========================关闭变量===========================

                public void jspDestroy()
                {
                    try
                    {
                        stmt.close(); //关闭Statement变量
                        con.close(); //关闭Connection变量
                        rs.close(); //关闭ResultSet变量
                    }
                    catch(Exception ex)
                    {
                        System.out.println(ex.toString());
                    }
                }

            %>

            <table width = "760" align = "center" >

            <%
                String course_id = new String(request.getParameter("course"));
                String unit_num = new String(request.getParameter("chapter"));
                String degreed = new String(request.getParameter("degreed"));
                String content = new String(request.getParameter("point"));

                if(course_id.equals(new String("0")))
                {
                out.println("<tr><td>请选择一个课程!</td></tr>");
                }
                else
                {
                    if(unit_num.equals(new String("0")))
                    {
                        out.println("<tr><td>请选择一个单元!</td></tr>");
                    }
                    else
                    {
                        if(degreed.equals(new String("0"))){
                            out.println("<tr><td>请选择一个难度系数!</td></tr>");
                        }
                        else
                        {
                            String sql = "insert into coursepoint(course_id,unit_num,degreed,content) values("+course_id+","+unit_num
                            +","+degreed+","+content+")";
                            jspInit();
                            int n = stmt.executeUpdate(sql);
                            jspDestroy();
                            out.println("<tr><td>You have enter one information point.<br><br>");
                            out.println("课程名:"+course_id);
                            out.println("<br><br>章节:"+unit_num);
                            out.println("<br><br>难度系数:"+degreed);
                            out.println("<br><br>内容:"+content+"</td></tr>");
                        }
                    }
                }

            %>
            </table>
        </form>
    </body>
</html>

14 楼

kingzhm [专家分：450] 发布于 2005-07-25 14:02:00

<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.lang.*, java.sql.* " %>
<html>

    <head>
        <title>录入成功</title>
    <head>

    <body>
        <form>
            <%
                Connection con = null;
                Statement stmt = null;
                ResultSet rs = null;
                //=======================执行数据库连结动作========================

                public void jspInit()
                {
                    try
                    {
                        Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); //载入驱动程式类别
                        con = DriverManager.getConnection("jdbcdbc:LocalServer"," "," "); //建立数据库连线
                        //建立Statement变量, 并设定记录指标类型为可前後移动
                        stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                        ResultSet.CONCUR_READ_ONLY);
                    }catch(Exception ex)
                    {
                        System.out.println(ex.toString());
                    }
                }

                //==========================关闭变量===========================

                public void jspDestroy()
                {
                    try
                    {
                        stmt.close(); //关闭Statement变量
                        con.close(); //关闭Connection变量
                        rs.close(); //关闭ResultSet变量
                    }
                    catch(Exception ex)
                    {
                        System.out.println(ex.toString());
                    }
                }

            %>

            <table width = "760" align = "center" >

            <%
                String course_id = new String(request.getParameter("course"));
                String unit_num = new String(request.getParameter("chapter"));
                String degreed = new String(request.getParameter("degreed"));
                String content = new String(request.getParameter("point"));

                if(course_id.equals(new String("0")))
                {
                out.println("<tr><td>请选择一个课程!</td></tr>");
                }
                else
                {
                    if(unit_num.equals(new String("0")))
                    {
                        out.println("<tr><td>请选择一个单元!</td></tr>");
                    }
                    else
                    {
                        if(degreed.equals(new String("0"))){
                            out.println("<tr><td>请选择一个难度系数!</td></tr>");
                        }
                        else
                        {
                            String sql = "insert into coursepoint(course_id,unit_num,degreed,content) values("+course_id+","+unit_num
                            +","+degreed+","+content+")";
                            jspInit();
                            int n = stmt.executeUpdate(sql);
                            jspDestroy();
                            out.println("<tr><td>You have enter one information point.<br><br>");
                            out.println("课程名:"+course_id);
                            out.println("<br><br>章节:"+unit_num);
                            out.println("<br><br>难度系数:"+degreed);
                            out.println("<br><br>内容:"+content+"</td></tr>");
                        }
                    }
                }

            %>
            </table>
        </form>
    </body>
</html>

15 楼

kingzhm [专家分：450] 发布于 2005-07-25 14:03:00

<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.lang.*, java.sql.* " %>
<html>

    <head>
        <title>录入成功</title>
    <head>

    <body>
        <form>
            <%
                Connection con = null;
                Statement stmt = null;
                ResultSet rs = null;
                //=======================执行数据库连结动作========================

                public void jspInit()
                {
                    try
                    {
                        Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); //载入驱动程式类别
                        con = DriverManager.getConnection("jdbcdbc:LocalServer"," "," "); //建立数据库连线
                        //建立Statement变量, 并设定记录指标类型为可前後移动
                        stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                        ResultSet.CONCUR_READ_ONLY);
                    }catch(Exception ex)
                    {
                        System.out.println(ex.toString());
                    }
                }

                //==========================关闭变量===========================

                public void jspDestroy()
                {
                    try
                    {
                        stmt.close(); //关闭Statement变量
                        con.close(); //关闭Connection变量
                        rs.close(); //关闭ResultSet变量
                    }
                    catch(Exception ex)
                    {
                        System.out.println(ex.toString());
                    }
                }

            %>

            <table width = "760" align = "center" >

            <%
                String course_id = new String(request.getParameter("course"));
                String unit_num = new String(request.getParameter("chapter"));
                String degreed = new String(request.getParameter("degreed"));
                String content = new String(request.getParameter("point"));

                if(course_id.equals(new String("0")))
                {
                out.println("<tr><td>请选择一个课程!</td></tr>");
                }
                else
                {
                    if(unit_num.equals(new String("0")))
                    {
                        out.println("<tr><td>请选择一个单元!</td></tr>");
                    }
                    else
                    {
                        if(degreed.equals(new String("0"))){
                            out.println("<tr><td>请选择一个难度系数!</td></tr>");
                        }
                        else
                        {
                            String sql = "insert into coursepoint(course_id,unit_num,degreed,content) values("+course_id+","+unit_num
                            +","+degreed+","+content+")";
                            jspInit();
                            int n = stmt.executeUpdate(sql);
                            jspDestroy();
                            out.println("<tr><td>You have enter one information point.<br><br>");
                            out.println("课程名:"+course_id);
                            out.println("<br><br>章节:"+unit_num);
                            out.println("<br><br>难度系数:"+degreed);
                            out.println("<br><br>内容:"+content+"</td></tr>");
                        }
                    }
                }

            %>
            </table>
        </form>
    </body>
</html>

16 楼

kingzhm [专家分：450] 发布于 2005-07-25 14:04:00

<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.lang.*, java.sql.* " %>
<html>

    <head>
        <title>录入成功</title>
    <head>

    <body>
        <form>
            <%
                Connection con = null;
                Statement stmt = null;
                ResultSet rs = null;
                //=======================执行数据库连结动作========================

                public void jspInit()
                {
                    try
                    {
                        Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); //载入驱动程式类别
                        con = DriverManager.getConnection("jdbcdbc:LocalServer"," "," "); //建立数据库连线
                        //建立Statement变量, 并设定记录指标类型为可前後移动
                        stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                        ResultSet.CONCUR_READ_ONLY);
                    }catch(Exception ex)
                    {
                        System.out.println(ex.toString());
                    }
                }

                //==========================关闭变量===========================

                public void jspDestroy()
                {
                    try
                    {
                        stmt.close(); //关闭Statement变量
                        con.close(); //关闭Connection变量
                        rs.close(); //关闭ResultSet变量
                    }
                    catch(Exception ex)
                    {
                        System.out.println(ex.toString());
                    }
                }

            %>

            <table width = "760" align = "center" >

            <%
                String course_id = new String(request.getParameter("course"));
                String unit_num = new String(request.getParameter("chapter"));
                String degreed = new String(request.getParameter("degreed"));
                String content = new String(request.getParameter("point"));

                if(course_id.equals(new String("0")))
                {
                out.println("<tr><td>请选择一个课程!</td></tr>");
                }
                else
                {
                    if(unit_num.equals(new String("0")))
                    {
                        out.println("<tr><td>请选择一个单元!</td></tr>");
                    }
                    else
                    {
                        if(degreed.equals(new String("0"))){
                            out.println("<tr><td>请选择一个难度系数!</td></tr>");
                        }
                        else
                        {
                            String sql = "insert into coursepoint(course_id,unit_num,degreed,content) values("+course_id+","+unit_num
                            +","+degreed+","+content+")";
                            jspInit();
                            int n = stmt.executeUpdate(sql);
                            jspDestroy();
                            out.println("<tr><td>You have enter one information point.<br><br>");
                            out.println("课程名:"+course_id);
                            out.println("<br><br>章节:"+unit_num);
                            out.println("<br><br>难度系数:"+degreed);
                            out.println("<br><br>内容:"+content+"</td></tr>");
                        }
                    }
                }

            %>
            </table>
        </form>
    </body>
</html>

17 楼

kingzhm [专家分：450] 发布于 2005-07-25 14:18:00

回3楼话，日期问题一，那个人是用ASP写的，怪那个人就是所问非所答，怪我的话就是不会ASP

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