HTTP Status 500 - 求解

[guangxircw]

HTTP Status 500 - 

--------------------------------------------------------------------------------

type Exception report

message 

description The server encountered an internal error () that prevented it from fulfilling this request.

exception 

org.apache.jasper.JasperException
	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:460)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:803)


root cause 

java.lang.NullPointerException
	org.apache.jsp.login_jsp._jspService(login_jsp.java:72)
	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:803)


note The full stack trace of the root cause is available in the Apache Tomcat/5.5.26 logs.

[shine333]

先会走，然后再跑

[guangxircw]

[Quote=引用 6 楼 soli11722984 的回复:]
System.out.println("rst = "+rst);
System.out.println("calendar = "+calendar);
[/Quote]



HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: Exception in JSP: /login.jsp:20

17: System.out.println("rs= "+rs);
18:
19: session.setAttribute("isLog",new String("0"));//判断用户是否登陆，当isLog的属性为0时，说明用户并没有登陆
20: if(!rs.next())//结果集没有找到所要查找的行
21: {
22: out.println("<script language='javascript'>alert('用户名或密码错误');"+
23: "parent.location.href='login.html';</script>");


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)


root cause

java.lang.NullPointerException
org.apache.jsp.login_jsp._jspService(login_jsp.java:79)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)


note The full stack trace of the root cause is available in the Apache Tomcat/5.5.26 logs.


--------------------------------------------------------------------------------

Apache Tomcat/5.5.26

[Mars_Ma_OK]

1.假设你的connection,statement都没有问题..

if(!rs.next())//结果集没有找到所要查找的行

这句,你不觉得,如果rs是null的情况有没? 如果有的话,这是一个NullPointException.
2.可以像8楼这样去打印..在你不确定对象是不是null的情况下,最好是打印or判断不为null在去调用其方法.

[nickDeLove]

可能有没有查出的结果集 rs可能为空

[hly_886]

[Quote=引用 6 楼 soli11722984 的回复:]
System.out.println("rst = "+rst);
System.out.println("calendar = "+calendar);
[/Quote]

如果 rst 或者 calendar 可能是null的话，你这样写就直接是空指针了
应该改成
out.println(rst);
out.println(rst);
就可以了

[guangxircw]

[Quote=引用 13 楼 hly_886 的回复:]
引用 6 楼 soli11722984 的回复:
System.out.println("rst = "+rst);
System.out.println("calendar = "+calendar);


如果 rst 或者 calendar 可能是null的话，你这样写就直接是空指针了
应该改成
out.println(rst);
out.println(rst);
就可以……
[/Quote]

还是提示一样的错误

[soli11722984]

[Quote=引用 11 楼 mars_ma_ok 的回复:]
1.假设你的connection,statement都没有问题..

Java code
if(!rs.next())//结果集没有找到所要查找的行

这句,你不觉得,如果rs是null的情况有没? 如果有的话,这是一个NullPointException.
2.可以像8楼这样去打印..在你不确定对象是不是null的情况下,最好是打印or判断不为null在去调用其方法.
[/Quote]

估计是connection,statement出毛病了

[guangxircw]

帮忙看看 connection,statement 有没有问题

package com.mingri.dbconn;

import java.sql.*;
import com.mingri.dbconn.DBConn;

public class DBResult
{
  private Connection con;
  public  DBResult(){
    this.con=DBConn.getConnection();
  }
  /**
   * 用于获得执行SQL语句的ResultSet对象
   */
  public ResultSet getResult(String sql){
    try{
      Statement stmt=con.createStatement();
      ResultSet rs=stmt.executeQuery(sql);
      return rs;
    }
    catch(Exception e){}
    return null;
  }
  /**
   * 用于执行SQL语句没有返回值
   */
  public void doExecute(String sql){
    try{
      Statement stmt=con.createStatement();
      stmt.executeQuery(sql);
    }catch(Exception e){}
  }
  /**
   * 用于获得执行SQL语句的PreparedStatement(预处理)对象
   */
  public PreparedStatement getPreparedStatement(String sql){
    try{
      PreparedStatement pstmt=con.prepareStatement(sql);
      return pstmt;
    }
    catch(Exception e){}
    return null;
  }
  /**
   * 关闭连接
   */
  public void closeCon(){
    try{
      this.con.close();
    }catch(Exception e){
        e.printStackTrace();
    }
  }
}

package com.mingri.dbconn;

import java.sql.*;
import com.mingri.dbconn.DBConn;

public class DBResult
{
  private Connection con;
  public  DBResult(){
    this.con=DBConn.getConnection();
  }
  /**
   * 用于获得执行SQL语句的ResultSet对象
   */
  public ResultSet getResult(String sql){
    try{
      Statement stmt=con.createStatement();
      ResultSet rs=stmt.executeQuery(sql);
      return rs;
    }
    catch(Exception e){}
    return null;
  }
  /**
   * 用于执行SQL语句没有返回值
   */
  public void doExecute(String sql){
    try{
      Statement stmt=con.createStatement();
      stmt.executeQuery(sql);
    }catch(Exception e){}
  }
  /**
   * 用于获得执行SQL语句的PreparedStatement(预处理)对象
   */
  public PreparedStatement getPreparedStatement(String sql){
    try{
      PreparedStatement pstmt=con.prepareStatement(sql);
      return pstmt;
    }
    catch(Exception e){}
    return null;
  }
  /**
   * 关闭连接
   */
  public void closeCon(){
    try{
      this.con.close();
    }catch(Exception e){
        e.printStackTrace();
    }
  }
}

[IAMJourney]

把rs、rst、calendar等对象都输出来看看

[soli11722984]

public ResultSet getResult(String sql){
try{
Statement stmt=con.createStatement();
ResultSet rs=stmt.executeQuery(sql);
return rs;
}
catch(Exception e){}
return null;
}
。。。。。。。把e的错误信息都打出来
等别人继续打你吧，下班

[soli11722984]

是答。。。。。。打错字

[guangxircw]

[Quote=引用 17 楼 hongzhonghong 的回复:]
把rs、rst、calendar等对象都输出来看看
[/Quote]

在10楼

[soli11722984]

晕，不是那段，是加上e.printStackTrace()，现在那段错误信息你没输出

[Mars_Ma_OK]

在公司里面,就我们公司来说,catch里面不能什么东西都不写的..如果有异常都没有处理,这是错误的..无声无息的就给默认了..我就给老大讲过, 知道可以是返回null,至少也要给点log呀..下班了..走人了

[tanxd39]

java.lang.NullPointerException
org.apache.jsp.login_jsp._jspService(login_jsp.java:79)

打开login_jsp.java文件，看79行就可以了

[jbz001]

已经看不懂这个了

[hepeng_8]

空指针 看看是不是那块没初始化

[空心兜兜]

空指针很常见
找起来也不难

[guangxircw]

[Quote=引用 27 楼 tangyu477 的回复:]
把这个JSP的WORK贴出来就一下找到了 瞎猜啥啊
WORK在TOMCAT根目录下 一直往下找 会找到JSP对应编译的JAVA类：login_jsp.java
把他贴出来不就完事了么
[/Quote]

login_jsp.java

package org.apache.jsp;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import java.io.*;
import java.sql.*;

public final class login_jsp extends org.apache.jasper.runtime.HttpJspBase
    implements org.apache.jasper.runtime.JspSourceDependent {

  private static java.util.List _jspx_dependants;

  public Object getDependants() {
    return _jspx_dependants;
  }

  public void _jspService(HttpServletRequest request, HttpServletResponse response)
        throws java.io.IOException, ServletException {

    JspFactory _jspxFactory = null;
    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 {
      _jspxFactory = JspFactory.getDefaultFactory();
      response.setContentType("text/html;charset=gb2312");
      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('\n');
      out.write('\n');
      com.mingri.dbconn.DBResult rst = null;
      synchronized (_jspx_page_context) {
        rst = (com.mingri.dbconn.DBResult) _jspx_page_context.getAttribute("rst", PageContext.PAGE_SCOPE);
        if (rst == null){
          rst = new com.mingri.dbconn.DBResult();
          _jspx_page_context.setAttribute("rst", rst, PageContext.PAGE_SCOPE);
        }
      }
      out.write('\n');
      com.mingri.showtime.ShowTime calendar = null;
      synchronized (_jspx_page_context) {
        calendar = (com.mingri.showtime.ShowTime) _jspx_page_context.getAttribute("calendar", PageContext.PAGE_SCOPE);
        if (calendar == null){
          calendar = new com.mingri.showtime.ShowTime();
          _jspx_page_context.setAttribute("calendar", calendar, PageContext.PAGE_SCOPE);
        }
      }
      out.write('\n');

   request.setCharacterEncoding("gb2312");//对请求进行统一编码，能正常接受到中文
   String username=request.getParameter("username"); //接收表单中的username属性
   String password=request.getParameter("password");//接收表单中的password属性
   String str="select * from tb_user where "+
               "username='"+username+"' and password='"+password+"'";
   ResultSet rs=rst.getResult(str);//执行SQL语句获得结果集对象
   session.setAttribute("isLog",new String("0"));//判断用户是否登陆，当isLog的属性为0时，说明用户并没有登陆
   if(!rs.next())//结果集没有找到所要查找的行
   {
    out.println("<script language='javascript'>alert('用户名或密码错误');"+
                "parent.location.href='login.html';</script>");
   }
   else
   {
     session.setAttribute("username",rs.getString("username"));//保存登录信息到session对象中
     session.setAttribute("password",rs.getString("password"));
     session.setAttribute("isLog",new String("1"));//将isLog属性设置为1
     //获得用户上次登陆系统的时间
     session.setAttribute("userLastLogTime",rs.getString("userLastLogTime"));
     String strsql=calendar.getDate();
     int id=rs.getInt("ID");
     //将该用户本次登陆系统的时间在用户信息表中更新
     String strUpdate="update tb_user set userLastLogTime='"+strsql+"' where ID="+id+"";
     rst.getResult(strUpdate);//执行SQL语句
     response.sendRedirect("chat.jsp");//登陆成功后转到系统主页面
   }

      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
      out.write("\n");
    } catch (Throwable t) {
      if (!(t instanceof SkipPageException)){
        out = _jspx_out;
        if (out != null && out.getBufferSize() != 0)
          out.clearBuffer();
        if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);
      }
    } finally {
      if (_jspxFactory != null) _jspxFactory.releasePageContext(_jspx_page_context);
    }
  }
}

[tfish2014]

把这个JSP的WORK贴出来就一下找到了 瞎猜啥啊
WORK在TOMCAT根目录下 一直往下找 会找到JSP对应编译的JAVA类：login_jsp.java
把他贴出来不就完事了么