在关于jsp的好几个问题````(1)的mail.jsp提交后
idea.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<head>
<title>意见箱</title>
</head>
<body bgcolor="#ffffff">
<div align="center"><font size="6">您的意见已提交!</font><font size="5">
<jsp:useBean id="m_idea" scope="request" class="idea.idea"/></font>
<%@ page import="java.io.*"%>
<%@ page import="java.util.*"%>
<%
java.util.Date m_date=new java.util.Date();
String m_time=m_date.toLocaleString();
String m_name=request.getParameter("name");
String m_mail=request.getParameter("mail");
String m_title=request.getParameter("title");
String m_content=request.getParameter("content");
byte[] tmpbyte=m_name.getBytes("ISO8859_1");
m_name=new String(tmpbyte);
tmpbyte=m_title.getBytes("ISO8859_1");
m_title=new String(tmpbyte);
tmpbyte=m_content.getBytes("ISO8859_1");
m_content=new String(tmpbyte);
int i;
do{
i=m_content.indexOf("&");
if(i>0)m_content=m_content.substring(0,i)+"&"+m_content.substring(i+1);
}while(m_content.indexOf("&")>0);
do{i=m_content.indexOf("<");
if(i>0)m_content=m_content.substring(0,i)+"<"+m_content.substring(i+1);}
while(m_content.indexOf("<")>0);
do{i=m_content.indexOf(">");
if(i>0)m_content=m_content.substring(0,i)+">"+m_content.substring(i+1);}
while(m_content.indexOf(">")>0);
do{i=m_content.indexOf("\r\n");
if(i>0)m_content=m_content.substring(0,i)+"<br>"+m_content.substring(i+2);}
while(m_content.indexOf("\r\n")>0);
m_idea.newFilePath=getServletConfig().getServletContext().getRealPath("/new.txt");
m_idea.oldFilePath=getServletConfig().getServletContext().getRealPath("/old.txt");
m_idea.createFile();
int num=Integer.parseInt(m_idea.readOldFile());
m_idea.writeNewFile(num+1);
m_idea.writeNewFile(m_name);
m_idea.writeNewFile(m_mail);
m_idea.writeNewFile(m_title);
m_idea.writeNewFile(m_content);
m_idea.writeNewFile(m_time);
String m_line;
do{
m_line=m_idea.readOldFile();
m_idea.writeNewFile(m_line);
}while(m_idea.flag);
m_idea.rename();
%></div><hr width="400" align="center">
<div align="center">
<table width="400" border="1" cellspacing="0" bordercolor="#ff3333">
<tr>
<td width="78">
<div align="right">姓名:</div>
</td>
<td width="96"><b><font color="#ff0000"><%=m_name%></font></b></td>
<td width="76"><div align="right">Email地址:</div></td>
<td width="123"><%="<a href=\"mailto:"+m_mail+"\">"+m_mail+"</a>"%></td></tr>
<tr>
<td width="78"><div align="right">意见主题:</div></td>
<td colspan="3"><%=m_title%></td></tr>
<tr>
<td width="78"><div align="right">意见内容:</div></td>
<td colspan="3"><%=m_content%></td></tr>
<tr>
<td width="78"><div align="right">发表时间:</div></td>
<td colspan="3"><%=m_time%></td></tr></table>
<hr width="400"><a href="index.jsp">写意见</a><a href="JavaScript:window.close()">
关闭窗口</a></div>
</body>
</html>
------------------------------------
idea.javapackage idea;
import java.io.*;
import java.util.*;
public class idea extends Object{
public String newFilePath="";
public String oldFilePath="";
private File newFile;
private File oldFile;
private BufferedReader oldFileRead;
private PrintWriter newFileWrite;
public boolean flag=true;
public String systemMessage="";
public void createFile()throws FileNotFoundException{
newFile=new File(newFilePath);
oldFile=new File(oldFilePath);
oldFileRead=new BufferedReader(new FileReader(oldFilePath));
newFileWrite=new PrintWriter(new FileOutputStream(newFilePath));
}
public void writeNewFile(String writeStr)throws FileNotFoundException{
newFileWrite.println(writeStr);
}
public void writeNewFile(java.util.Date writeStr)throws FileNotFoundException{
newFileWrite.println(writeStr);
}
public void writeNewFile(int writeStr)throws FileNotFoundException{
newFileWrite.println(writeStr);
}
public String readOldFile()throws FileNotFoundException{
String readStr="";
try{
readStr=oldFileRead.readLine();
if(readStr.compareTo("<!--end-->")==0){
flag=false;
}
}catch(IOException e){
flag=true;
}
return readStr;
}
public void rename()throws FileNotFoundException{
newFileWrite.close();
try{
oldFileRead.close();
}catch(IOException e){
systemMessage=e.toString();
}
flag=oldFile.delete();
flag=newFile.renameTo(oldFile);
}
}
tomcat 报错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:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause java.lang.NullPointerException
idea.idea.readOldFile(idea.java:32)
org.apache.jsp.idea_jsp._jspService(idea_jsp.java:95)
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:332)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)请问怎么回事呢 谢谢大家了~
idea.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<head>
<title>意见箱</title>
</head>
<body bgcolor="#ffffff">
<div align="center"><font size="6">您的意见已提交!</font><font size="5">
<jsp:useBean id="m_idea" scope="request" class="idea.idea"/></font>
<%@ page import="java.io.*"%>
<%@ page import="java.util.*"%>
<%
java.util.Date m_date=new java.util.Date();
String m_time=m_date.toLocaleString();
String m_name=request.getParameter("name");
String m_mail=request.getParameter("mail");
String m_title=request.getParameter("title");
String m_content=request.getParameter("content");
byte[] tmpbyte=m_name.getBytes("ISO8859_1");
m_name=new String(tmpbyte);
tmpbyte=m_title.getBytes("ISO8859_1");
m_title=new String(tmpbyte);
tmpbyte=m_content.getBytes("ISO8859_1");
m_content=new String(tmpbyte);
int i;
do{
i=m_content.indexOf("&");
if(i>0)m_content=m_content.substring(0,i)+"&"+m_content.substring(i+1);
}while(m_content.indexOf("&")>0);
do{i=m_content.indexOf("<");
if(i>0)m_content=m_content.substring(0,i)+"<"+m_content.substring(i+1);}
while(m_content.indexOf("<")>0);
do{i=m_content.indexOf(">");
if(i>0)m_content=m_content.substring(0,i)+">"+m_content.substring(i+1);}
while(m_content.indexOf(">")>0);
do{i=m_content.indexOf("\r\n");
if(i>0)m_content=m_content.substring(0,i)+"<br>"+m_content.substring(i+2);}
while(m_content.indexOf("\r\n")>0);
m_idea.newFilePath=getServletConfig().getServletContext().getRealPath("/new.txt");
m_idea.oldFilePath=getServletConfig().getServletContext().getRealPath("/old.txt");
m_idea.createFile();
int num=Integer.parseInt(m_idea.readOldFile());
m_idea.writeNewFile(num+1);
m_idea.writeNewFile(m_name);
m_idea.writeNewFile(m_mail);
m_idea.writeNewFile(m_title);
m_idea.writeNewFile(m_content);
m_idea.writeNewFile(m_time);
String m_line;
do{
m_line=m_idea.readOldFile();
m_idea.writeNewFile(m_line);
}while(m_idea.flag);
m_idea.rename();
%></div><hr width="400" align="center">
<div align="center">
<table width="400" border="1" cellspacing="0" bordercolor="#ff3333">
<tr>
<td width="78">
<div align="right">姓名:</div>
</td>
<td width="96"><b><font color="#ff0000"><%=m_name%></font></b></td>
<td width="76"><div align="right">Email地址:</div></td>
<td width="123"><%="<a href=\"mailto:"+m_mail+"\">"+m_mail+"</a>"%></td></tr>
<tr>
<td width="78"><div align="right">意见主题:</div></td>
<td colspan="3"><%=m_title%></td></tr>
<tr>
<td width="78"><div align="right">意见内容:</div></td>
<td colspan="3"><%=m_content%></td></tr>
<tr>
<td width="78"><div align="right">发表时间:</div></td>
<td colspan="3"><%=m_time%></td></tr></table>
<hr width="400"><a href="index.jsp">写意见</a><a href="JavaScript:window.close()">
关闭窗口</a></div>
</body>
</html>
------------------------------------
idea.javapackage idea;
import java.io.*;
import java.util.*;
public class idea extends Object{
public String newFilePath="";
public String oldFilePath="";
private File newFile;
private File oldFile;
private BufferedReader oldFileRead;
private PrintWriter newFileWrite;
public boolean flag=true;
public String systemMessage="";
public void createFile()throws FileNotFoundException{
newFile=new File(newFilePath);
oldFile=new File(oldFilePath);
oldFileRead=new BufferedReader(new FileReader(oldFilePath));
newFileWrite=new PrintWriter(new FileOutputStream(newFilePath));
}
public void writeNewFile(String writeStr)throws FileNotFoundException{
newFileWrite.println(writeStr);
}
public void writeNewFile(java.util.Date writeStr)throws FileNotFoundException{
newFileWrite.println(writeStr);
}
public void writeNewFile(int writeStr)throws FileNotFoundException{
newFileWrite.println(writeStr);
}
public String readOldFile()throws FileNotFoundException{
String readStr="";
try{
readStr=oldFileRead.readLine();
if(readStr.compareTo("<!--end-->")==0){
flag=false;
}
}catch(IOException e){
flag=true;
}
return readStr;
}
public void rename()throws FileNotFoundException{
newFileWrite.close();
try{
oldFileRead.close();
}catch(IOException e){
systemMessage=e.toString();
}
flag=oldFile.delete();
flag=newFile.renameTo(oldFile);
}
}
tomcat 报错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:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause java.lang.NullPointerException
idea.idea.readOldFile(idea.java:32)
org.apache.jsp.idea_jsp._jspService(idea_jsp.java:95)
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:332)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)请问怎么回事呢 谢谢大家了~
String readStr="";
try{
readStr=oldFileRead.readLine();
if(readStr.compareTo("<!--end-->")==0){
flag=false;
}
}catch(IOException e){
flag=true;
}
return readStr;
}检查这个方法,有空指针