What I am trying to do is read file and send the text to jsp
first, I read the context of my text file from fileGet.java. Then using request.setAttribute("chat", chat), I want to send the context to Live_index6.jsp
However, as I use request.getAttribute("chat") in Live_index6.jsp to receive the data, it kept print "null"
I checked that request.getAtrribute successfully printed the data I wanted in fileController.java, but it does not in Live_index6.jsp
I searched internet and it said code in controller
RequestDispatcher rd1 = request.getRequestDispatcher(str);
rd1.forward(request, response);
will send the request data to place where I directed, which is str == "Live_index6.jsp" that I setted.
can you guys please check my code and what is the problem?
Thank you so much!
this is my Live_index6.jsp
<%@page import="java.util.ArrayList"%>
<%@ page language="java" contentType="text/html; charset=EUC-KR"
pageEncoding="EUC-KR"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="EUC-KR">
<title>Insert title here</title>
<script src="jquery-3.3.1.js"></script>
<style>
textarea {
width: 300px;
height: 300px;
}
</style>
</head>
<body>
<% String user = request.getParameter("userName");
user = "hong";
%>
<%=request.getAttribute("chat") %>
<h3>Chat</h3>
<textarea row = "20" col="50" readonly id = "ta1">
</textarea><br>
<h3>Who?</h3>
<input type = "Text" id = "who1" value = "<%=user%>" height = "300px" disabled>
<h4>보낼 글</h4>
<input type = "text" id = "chat1" onkeyup="enterkey()">
<input type = "button" value = "가자" onclick="insertFile(); kajaChool()">
<br>
귓속말시 /wnickname (chatting)을 해야합니다. 닉네임과 chatting에 빈공간이 없을시 귓속말이 안보내집니다.
<script>
window.onload = function(){
const name = document.getElementById("who1").value;
$.ajax({ // $.ajax() $.get $.post
url:"getAllFile.do",
data: {
name : name
}, // kaja.jsp?irum=hong&na2=35
dataType:"text",
type:"post",
success: function(result1){
//place where I want to print my file context
alert();
},
error: function(xhr1,status){
alert("에러상태: " "\t" xhr1.status);
}
});
}
function enterkey(){
if(window.event.keyCode == 13){
insertFile();
kajaChool();
}
}
function insertFile(){
const name = document.getElementById("who1").value;
const chat = document.getElementById("chat1").value;
$.ajax({ // $.ajax() $.get $.post
url:"insertFile.do",
data: {
name : name,
chat : chat
}, // kaja.jsp?irum=hong&na2=35
dataType:"text",
type:"post",
success: function(result1){
},
error: function(xhr1,status){
alert("error: " "\t" xhr1.status);
}
});
}
function kajaChool(){
document.getElementById("who1").disabled = true;
var tmp = document.getElementById("chat1").value;
if(tmp.substring(0,2) != "/w"){
ta1.value = "[" who1.value "]" chat1.value "\n";
ws1.send("[" who1.value "]" chat1.value);
}else{
var index = tmp.indexOf(" ") 1;
var toNickName = tmp.substring(2,index-1);
if(true){
ta1.value = "[" who1.value "]" " >> " "[" toNickName "]" tmp.substring(index) "\n";
ws1.send("[" who1.value "]" chat1.value);
}else{
alert("존재하지 않는 닉네임입니다.");
chat1.value = "";
chat1.focuse();
return;
}
}
/*
if(tmp.indexOf("/w") == -1){
ta1.value = "[" who1.value "]" chat1.value "\n";
}else{
var index = tmp.indexOf(" ") 1;
var toNickName = tmp.substring(2,index-1);
ta1.value = "[" who1.value "]" " >> " "[" toNickName "]" tmp.substring(index) "\n";
}
*/
// ws1.send("[" who1.value "]" chat1.value);
chat1.value = "";
chat1.focuse();
}
</script>
<script>
const ws1 = new WebSocket("ws://localhost:8080/Live_Chat6/kaja");
const ta1 = document.getElementById("ta1");
ws1.onerror = function(aa){
alert("error");
};
ws1.onopen = function(aa){
alert("[chat]");
who1.focus();
who1.select();
};
ws1.onmessage = function(aa){
const name = document.getElementById("who1").value;
const arr = aa.data.split("]");
const tmp = arr[1];
const comp = tmp.substring(0,2) == "/w" ;
//ta1.value = comp "\n";
if(comp){
var index = tmp.indexOf(" ") 1;
var toNickName = tmp.substring(2,index-1);
if(name == toNickName){
ta1.value = "[" arr[0].substring(1) "] >> " "[" toNickName "]" tmp.substring(index) "\n";
}
}else{
ta1.value = aa.data "\n";
}
};
</script>
</body>
</html>
my FileController.java
package frontController;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import Services.fileGet;
import Services.fileImpl;
import Services.fileInsert;
/**
* Servlet implementation class FileController
*/
@WebServlet("*.do")
public class FileController extends HttpServlet {
/**
* @see HttpServlet#HttpServlet()
*/
public FileController() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//response.getWriter().append("Served at: ").append(request.getContextPath());
System.out.println("완료");
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//doGet(request, response);
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
/*******************************/
String c =request.getRequestURI().substring
(request.getContextPath().length());
/**********************************/
String str = "Live_index6.jsp"; ///////////
fileImpl fi = null;
switch(c) {
case "/insertFile.do":
fi = new fileInsert();
try {
fi.fileWork(request, response);
}catch(Exception e){
System.out.println(e.getMessage());
}
break;
case "/getAllFile.do":
fi = new fileGet();
try {
fi.fileWork(request, response);
}catch(Exception e) {
System.out.println(e.getMessage());
}
break;
} //swich -end
//String chat = (String) request.getAttribute("chat");
//System.out.println(chat);
RequestDispatcher rd1 = request.getRequestDispatcher(str);
rd1.forward(request, response);
}
}
My fileGet.java
package Services;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.util.ArrayList;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class fileGet implements fileImpl{
@Override
public void fileWork(HttpServletRequest request, HttpServletResponse response) throws Exception {
// TODO Auto-generated method stub
String path = request.getSession().getServletContext().getRealPath("/") "/Chat_Log/chat_log.txt";
//String path = "c:/Chat_Log/chat_log.txt";
//ArrayList<String> chat = new ArrayList<String>();
String chat = "";
try{
File file = new File(path);
FileReader filereader = new FileReader(file);
BufferedReader bufReader = new BufferedReader(filereader);
String line = "";
while((line = bufReader.readLine()) != null){
chat = line "\n";
}
bufReader.close();
}catch (Exception e) {
System.out.println(e.getMessage());
}
request.setAttribute("chat", chat);
}
}
CodePudding user response：
I faced same problem and to solve it I used HttpSession instead of request and response.sendRedirect instead of requestDispatcher this is the code that I used, you need only to reform it
session.setAttribute("eqmsg", "Equipment Added Successfully");
response.sendRedirect("http://localhost:8080/SmartFarmManagementSystem/addView.jsp");