严重: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at org.apache.jsp.inputCheck_jsp._jspService(inputCheck_jsp.java:76)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
jsp代码
<%@page import="java.sql.*"%>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>数据更新后的页面</title>
</head>
<body>
<center>
<h3>已添加学生信息</h3>
<hr>
<%
String studentNumber=request.getParameter("studentNumber");
byte b []=studentNumber.getBytes("ISO-8859-1");
studentNumber=new String(b,"UTF-8");
String studentName=request.getParameter("studentName");
byte b1 []=studentName.getBytes("ISO-8859-1");
studentName=new String(b1,"UTF-8");
String studentSex=request.getParameter("studentSex");
byte b2 []=studentSex.getBytes("ISO-8859-1");
studentSex=new String(b2,"UTF-8");
String studentAge=request.getParameter("studentAge");
byte b3 []=studentAge.getBytes("ISO-8859-1");
studentAge=new String(b3,"UTF-8");
String studentWeight=request.getParameter("studentWeight");
byte b4 []=studentWeight.getBytes("ISO-8859-1");
studentWeight=new String(b4,"UTF-8");
Class.forName("com.mysql.jdbc.Driver");
String url="jdbc:mysql://localhost:3333/pubs?useUnicode=true&characterEncoding=gbk";
Connection conn=DriverManager.getConnection(url,"root","123456");
Statement stmt=conn.createStatement();
String sql="insert into info values('"+studentNumber+"','"+studentName+"','"+studentSex+"',"+studentAge+","+studentWeight+")";
stmt.executeUpdate(sql);
stmt.close();
conn.close();
%>
<h3>已更改学生信息</h3>
<hr>
<%
Class.forName("com.mysql.jdbc.Driver");
String url1="jdbc:mysql://localhost:3333/pubs?useUnicode=true&characterEncoding=gbk";
Connection conn1=DriverManager.getConnection(url1,"root","123456");
Statement stmt1=conn1.createStatement();
String sql1="update info set studentAge=18";
stmt1.executeUpdate(sql1);
stmt1.close();
conn1.close();
%>
<h3>已删除学生信息</h3>
<hr>
<%
Class.forName("com.mysql.jdbc.Driver");
String url2="jdbc:mysql://localhost:3333/pubs?useUnicode=true&characterEncoding=gbk";
Connection conn2=DriverManager.getConnection(url1,"root","123456");
Statement stmt2=conn2.createStatement();
String sql2="delete from info where studentSex='男'";
stmt2.executeUpdate(sql2);
stmt2.close();
conn2.close();
%>
<h3>经过以上操作后,数据库中有以下记录</h3>
<hr>
<table border=2 bgcolor="ccceee" align="center">
<tr>
<td>学号</td>
<td>姓名</td>
<td>性别</td>
<td>年龄</td>
<td>体重</td>
</tr>
<%
Class.forName("com.mysql.jdbc.Driver");
String url3="jdbc:mysql://localhost:3333/pubs?useUnicode=true&characterEncoding=gbk";
Connection conn3=DriverManager.getConnection(url3,"root","123456");
Statement stmt3=conn3.createStatement();
String sql3="select * from info";
ResultSet rs=stmt3.executeQuery(sql3);
while(rs.next()){
%>
<tr>
<td><%=rs.getString("studentNumber") %></td>
<td><%=rs.getString("studentName") %></td>
<td><%=rs.getString("studentSex") %></td>
<td><%=rs.getString("studentAge") %></td>
<td><%=rs.getString("studentWeight") %></td>
</tr>
<%}
rs.close();
stmt3.close();
conn3.close();
%>
</table>
<hr>
</center>
</body>
</html>