本人刚学javaweb,属于菜鸟,问个问题。我做了一个jsp网页,里面有个表单,提交到本网页的。通过向表单里填写信息,查询数据库。可是出错报出异常,以下是代码。
<body>
<table align="center" bgcolor="FF9999" border=1 width="500">
<form name="form1" method="get" action="zhengti.jsp">
<tr>
<td align="center">数据查询</td>
<td><select name="select">
<option value="学号" selected>学号</option>
<option value="姓名">姓名</option>
<option value="班级">班级</option>
</select></td>
<td><input type="text" size=10 name="t1"></td>
<td><input type="submit" value="查询" name="cha"></td>
</tr>
</form>
</table>
<%! String odbcQuery; %>
<%
String leibie=request.getParameter("select");
if(leibie!=null)
{
leibie=new String(leibie.getBytes("ISO-8859-1"));
}
String chaxun=request.getParameter("t1");
if(chaxun!=null)
{
chaxun=(new String(chaxun.getBytes("ISO-8859-1"))).trim();
}
if(leibie.equals("学号"))
{
odbcQuery="Selcet* form glz where 学号 like'%"+chaxun+"%'";
}
else if(leibie.equals("姓名"))
{
odbcQuery="Selcet* form glz where 姓名 like'%"+chaxun+"%'";
}
else if(leibie.equals("班级"))
{
odbcQuery="Select* form glz where 班级 like'%"+chaxun+"%'";
}
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDrier");
}catch(ClassNotFoundException e){}
try
{
Connection con=DriverManager.getConnection("jdbc:odbc:as");
Statement sql=con.createStatement();
ResultSet rs=sql.executeQuery(odbcQuery);
%>
<table align="center" border=1 width="500">
<tr>
<td bgcolor="0099FF" align="center">学号</td>
<td bgcolor="0099FF" align="center">姓名</td>
<td bgcolor="0099FF" align="center">性别</td>
<td bgcolor="0099FF" align="center">年龄</td>
<td bgcolor="0099FF" align="center">班级</td>
</tr>
<%
while(rs.next())
{
%>
<tr>
<td><%rs.getInt("学号");%></td>
<td><%rs.getString("姓名");%></td>
<td><%rs.getString("性别");%></td>
<td><%rs.getInt("年龄");%></td>
<td><%rs.getString("班级");%></td>
</tr>
<% }
rs.close();
sql.close();
con.close();
}catch(SQLException ee){}
%>
</table>
</body>
以下是异常
org.apache.jasper.JasperException: An exception occurred processing JSP page /zhengti.jsp at line 44
41: <%!
42: String odbcQuery;
43: %>
44: <% String leibie=request.getParameter("select");
45: if(leibie!=null)
46: {
47: leibie=new String(leibie.getBytes("ISO-8859-1")); org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:554)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:431)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:319)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause java.lang.NullPointerException
org.apache.jsp.zhengti_jsp._jspService(zhengti_jsp.java:114)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:389)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:319)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)请问下哪里出现错误了,我看是空指针异常,可是我的变量应该都获取到了呀~求解释~
<body>
<table align="center" bgcolor="FF9999" border=1 width="500">
<form name="form1" method="get" action="zhengti.jsp">
<tr>
<td align="center">数据查询</td>
<td><select name="select">
<option value="学号" selected>学号</option>
<option value="姓名">姓名</option>
<option value="班级">班级</option>
</select></td>
<td><input type="text" size=10 name="t1"></td>
<td><input type="submit" value="查询" name="cha"></td>
</tr>
</form>
</table>
<%! String odbcQuery; %>
<%
String leibie=request.getParameter("select");
if(leibie!=null)
{
leibie=new String(leibie.getBytes("ISO-8859-1"));
}
String chaxun=request.getParameter("t1");
if(chaxun!=null)
{
chaxun=(new String(chaxun.getBytes("ISO-8859-1"))).trim();
}
if(leibie.equals("学号"))
{
odbcQuery="Selcet* form glz where 学号 like'%"+chaxun+"%'";
}
else if(leibie.equals("姓名"))
{
odbcQuery="Selcet* form glz where 姓名 like'%"+chaxun+"%'";
}
else if(leibie.equals("班级"))
{
odbcQuery="Select* form glz where 班级 like'%"+chaxun+"%'";
}
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDrier");
}catch(ClassNotFoundException e){}
try
{
Connection con=DriverManager.getConnection("jdbc:odbc:as");
Statement sql=con.createStatement();
ResultSet rs=sql.executeQuery(odbcQuery);
%>
<table align="center" border=1 width="500">
<tr>
<td bgcolor="0099FF" align="center">学号</td>
<td bgcolor="0099FF" align="center">姓名</td>
<td bgcolor="0099FF" align="center">性别</td>
<td bgcolor="0099FF" align="center">年龄</td>
<td bgcolor="0099FF" align="center">班级</td>
</tr>
<%
while(rs.next())
{
%>
<tr>
<td><%rs.getInt("学号");%></td>
<td><%rs.getString("姓名");%></td>
<td><%rs.getString("性别");%></td>
<td><%rs.getInt("年龄");%></td>
<td><%rs.getString("班级");%></td>
</tr>
<% }
rs.close();
sql.close();
con.close();
}catch(SQLException ee){}
%>
</table>
</body>
以下是异常
org.apache.jasper.JasperException: An exception occurred processing JSP page /zhengti.jsp at line 44
41: <%!
42: String odbcQuery;
43: %>
44: <% String leibie=request.getParameter("select");
45: if(leibie!=null)
46: {
47: leibie=new String(leibie.getBytes("ISO-8859-1")); org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:554)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:431)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:319)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause java.lang.NullPointerException
org.apache.jsp.zhengti_jsp._jspService(zhengti_jsp.java:114)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:389)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:319)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)请问下哪里出现错误了,我看是空指针异常,可是我的变量应该都获取到了呀~求解释~
貌似这个没有获取到,为空啊
还有这个错误,大家帮我看一下吧!
2011-11-2 21:08:53 org.apache.catalina.core.ApplicationContext log
信息: Marking servlet IndexServlet as unavailable
2011-11-2 21:08:53 org.apache.catalina.core.ApplicationContext log
严重: Error loading WebappClassLoader
context: /Company
delegate: false
repositories:
/WEB-INF/classes/
----------> Parent Classloader:
org.apache.catalina.loader.StandardClassLoader@1de9ac4
s2jsp.bysi.servlet.IndexServlet
java.lang.ClassNotFoundException: s2jsp.bysi.servlet.IndexServlet
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1647)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1493)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1095)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:809)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:129)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:619)
2011-11-2 21:08:53 org.apache.catalina.core.StandardWrapperValve invoke
严重: Allocate exception for servlet IndexServlet
java.lang.ClassNotFoundException: s2jsp.bysi.servlet.IndexServlet
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1647)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1493)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1095)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:809)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:129)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:619)