jsp程序，进入网页中。注册一个新用户时，报错,哪位帮忙看一下？？？谢谢

Question

jsp注册新用户时，报错,哪位帮忙看一下？？？
type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: java.lang.IllegalStateException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:532)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:420)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause java.lang.IllegalStateException
org.apache.catalina.connector.ResponseFacade.sendRedirect(ResponseFacade.java:435)
org.apache.jsp.WebContent.register_005fnew_005fuser_jsp._jspService(register_005fnew_005fuser_jsp.java:116)
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:384)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
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/6.0.10 logs.

Answer 1

org.apache.jsp.WebContent.register_005fnew_005fuser_jsp._jspService(register_005fnew_005fuser_jsp.java:116) 去 tomcat/work 
子目录下面找到这个register_005fnew_005fuser_jsp.java看看第116行为何为null

Answer 2

把页面缓存改大些试试，应该是 sendRedirect 时响应已经被提交了（响应数据已经开始向客户端发送了）。

Answer 3

register_005fnew_005fuser_jsp.java里的内容是 package org.apache.jsp.WebContent;import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import java.sql.*;public final class register_005fnew_005fuser_jsp extends org.apache.jasper.runtime.HttpJspBase
    implements org.apache.jasper.runtime.JspSourceDependent {  private static final JspFactory _jspxFactory = JspFactory.getDefaultFactory();  private static java.util.List _jspx_dependants;  private javax.el.ExpressionFactory _el_expressionfactory;
  private org.apache.AnnotationProcessor _jsp_annotationprocessor;  public Object getDependants() {
    return _jspx_dependants;
  }  public void _jspInit() {
    _el_expressionfactory = _jspxFactory.getJspApplicationContext(getServletConfig().getServletContext()).getExpressionFactory();
    _jsp_annotationprocessor = (org.apache.AnnotationProcessor) getServletConfig().getServletContext().getAttribute(org.apache.AnnotationProcessor.class.getName());
  }  public void _jspDestroy() {
  }  public void _jspService(HttpServletRequest request, HttpServletResponse response)
        throws java.io.IOException, ServletException {    PageContext pageContext = null;
    HttpSession session = null;
    ServletContext application = null;
    ServletConfig config = null;
    JspWriter out = null;
    Object page = this;
    JspWriter _jspx_out = null;
    PageContext _jspx_page_context = null;
    try {
      response.setContentType("text/html;charset=gbk");
      pageContext = _jspxFactory.getPageContext(this, request, response,
       null, true, 8192, true);
      _jspx_page_context = pageContext;
      application = pageContext.getServletContext();
      config = pageContext.getServletConfig();
      session = pageContext.getSession();
      out = pageContext.getOut();
      _jspx_out = out;      out.write("\r\n");
      out.write("\r\n");    //设置提交表单的中文编码
    request.setCharacterEncoding("GBK");    //获取用户输入表单
    String sUsername, sPassword, sRealname;
    sUsername=request.getParameter("username");
    sUsername=sUsername.replaceAll("'","''");
    sPassword=request.getParameter("password");
    sPassword=sPassword.replaceAll("'","''");
    sRealname=request.getParameter("realname");
    sRealname=sRealname.replaceAll("'","''");
    //准备插入语句
    String insertquery = "insert into player_info set username = '" + sUsername
                       + "', password = '" + sPassword 
                       + "', realname = '" + sRealname + "'";
    //检查用户是否存在语句
    String selectquery = "select * from player_info where username = '" + sUsername +"'";
    
    Connection conn=null;
    Statement stmt=null;
    ResultSet rs=null;
    try
    {
        //获得数据库链接
        Class.forName("com.mysql.jdbc.Driver").newInstance();
        conn = DriverManager.getConnection("jdbc:mysql://localhost/ch02?user=jspdb&password=jspdb");  
        //创建statement
        stmt = conn.createStatement();
        rs = stmt.executeQuery(selectquery);
        //查看是否已经有了用户
        if (rs.next()) 
        {
            response.sendRedirect("register.htm");
            return;
        }
        else
        {       
            //创建新用户
            stmt.executeUpdate(insertquery);
        }
    }catch(SQLException ex)
    {
        ex.printStackTrace();
        response.sendRedirect("welcom.htm");
    }
    finally
    {
        //关闭数据库链接
        if(stmt!=null) 
          stmt.close(); 
      if(conn!=null) 
        conn.close();     }
    //设置session属性
    session.setAttribute("username", sUsername);
    session.setAttribute("realname", sRealname);   
    
    //注册成功即意味着登录成功，迁移到游戏选择画面
    response.sendRedirect("entry.jsp");        out.write('\r');
      out.write('\n');
    } catch (Throwable t) {
      if (!(t instanceof SkipPageException)){
        out = _jspx_out;
        if (out != null && out.getBufferSize() != 0)
          try { out.clearBuffer(); } catch (java.io.IOException e) {}
        if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);
      }
    } finally {
      _jspxFactory.releasePageContext(_jspx_page_context);
    }
  }

Answer 4

    //注册成功即意味着登录成功，迁移到游戏选择画面 
    response.sendRedirect("entry.jsp");        out.write('\r'); 
      out.write('\n'); 
红色部分有问题吧，你都跳转页面了还输出，试一下，是不是这里有问题？？？？