问题描述
- jsp 页面这样，然后服务器抛出空指针错误
-
<%@ page contentType = "text/html;charset= gbb2312" %> <%@ page language = "java" pageEncoding = "gb2312" %> <%@ page import = "java.util.*" %> <%@ page import = "java.sql.*"%> <html> <head> 你好,本页面提供到库登记</head> <body> <form name = "form" action = "" method = "post"> <p>入库单编号<input type = "text" name = "id" value = "2"> <br><p>对应教材库的编号<input type = "text" name = "textbookId" value= "1" > <br><p>入库数量<input type = "text" name ="amount" value = "9"> <br><p>入库日期<inpt type = "text" name = "arrivalDate" value ="12-23-2"> <br><div align = "right"><input type = "submit" name ="submit" value = "录入" /> </div></form> </body> </html> <%!int id, textbookId, amount, rs; %> <% String ids = request.getParameter("id"); String textbookIds = request.getParameter("textbokId"); String amounts = request.getParameter("amount"); String arrivalDate = request.getParameter("arrivalDate"); // StringBuffer str =new StringBuffer(); //下面进行数据类型装换 if(ids != null) id = Integer.parseInt(ids); if(textbookIds != null) textbookId = Integer.parseInt(textbookIds); if(null != amounts) amount = Integer.parseInt(amounts); //进行数据库的验证 try{ Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver").newInstance(); }catch(Exception e){System.out.println(e);} try{ String url = "jdbc:sqlserver://localhost:1433;DatabaseName=Dian"; Connection connection = DriverManager.getConnection(url,"chen","chen"); Statement stmt = connection.createStatement(); String sql = "insert into arrival_book values("+id+","+textbookId+","+amount+",'"+arrivalDate+"');"; if(id != 0) rs = stmt.executeUpdate(sql); if(0 != rs) { // New location to be redirected String site = new String("addsuccess.jsp"); response.setStatus(response.SC_MOVED_PERMANENTLY);//实现页面重定向 response.setHeader("location", site); } else { response.sendRedirect("add1.jsp"); // str.append("添加失败"); } }catch(Exception e){ System.out.println("2222222"); }%>然后下面服务器
严重: Error processing request
java.lang.NullPointerException
at org.apache.catalina.connector.OutputBuffer.realWriteChars(OutputBuffer.java:457)
at org.apache.tomcat.util.buf.CharChunk.flushBuffer(CharChunk.java:393)
at org.apache.catalina.connector.OutputBuffer.close(OutputBuffer.java:275)
at org.apache.catalina.connector.Response.finishResponse(Response.java:453)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:578)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1081)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1566)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1523)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:744)## ## 求助？？？？
解决方案
页面这样，然后服务器抛出空指针错误
解决方案二：
错误输出只有这些吗？
解决方案三：
为啥要把java代码写在jsp页面，这是很不程序员的一种方式。