Tomcat 404 ошибка idea

As previous answers mentioned before, you’re using Spring Boot, which has its embedded Tomcat server under the hood. It’s the default behavior, but you may configure your Spring Boot project to use Netty or Undertow servers, please check more details here — Embedded Web Servers

So since you already have the Tomcat server, there is no need to configure it in your IDE. Also, worth mentioning that running a project from your IDE is not the best idea. Especially, when you’re describing your steps for reproducing the issue to someone else. Instead, you may run your Spring Boot project from the command line using the such command:

mvn spring-boot:run

By default, it’ll start your application on the 8080 port and you will be able to access your homepage at this URL: localhost:8080/home

For more details on running your Spring Boot application, you may check this document — Running your application

To run the Spring Boot project from your IntelliJ IDEA, you need to open the DemoApplication class (in your case), which has the main method. And on the left, there should be a play button for running your project. You can also configure it in the ‘Edit configurations’ menu by selecting the ‘Spring Boot’ item under the ‘Add new configuration’ menu.

Updated:

I’m using that you’re using macOS. To identify the process running on the 8080 port, which prevents you from starting your Spring Boot application, you may use such command:

sudo lsof -i :8080

This is the example output of this command from my machine, which has the Docker container running on the 8080 port:

COMMAND    PID     USER   FD   TYPE            DEVICE SIZE/OFF NODE NAME
com.docke 3134 golovnya  174u  IPv6 0xcaf3b5f3fb45111      0t0  TCP *:http-alt (LISTEN)

Here we’re interested in PID, which stands for the process identifier. It’s a unique id of the running application. In my case, the PID of the process running on the 8080 port is 3134. Knowing this, we may kill this process by the following command:

kill -9 <PID>

In my case it will look like this:

kill -9 3134

That’s all.

P.S. If it looks a bit complicated to your or you experience some issues, reloading your machine is always not a bad idea.

Tomcat сообщает об ошибке, когда IntelliJ IDEA запускает проект: не удалось загрузить ресурс

В первый раз, когда я использую IntelliJ IDEA, я использовал eclipse раньше

Я с радостью готовился испытать новые инструменты разработки, но как только проект импорта начался, у меня возникла ошибка

После импорта проекта и настройки jdk tomcat запустится со следующей ошибкой:

Failed to load resource: the server responded with a status of 404 (Not Found)

Я думал, что это проблема с импортом Tomcat, поэтому долго менял.

Наконец обнаружил, что это была очень простая ошибка, решение заключается в следующем:

Нажмите 【Edit configurations…], выберите импортированный Tomcat, как показано ниже:

! ! нота! !
Имя хвоста URL в [server] должно совпадать с именем Application Context в [deployment]! ! (Расположение ① и ② на следующих двух рисунках)

Решено ~~ Кто бы мог подумать, что я чуть не переустановил его заново. .

Наконец-то я могу счастливо поиграть с IntelliJ IDEA

I’m having a problem with my first Web Application. I use IntelliJ as IDE and Tomcat as Webserver.
Every servlet I’ve tried to acces, throws an 404 Error. Even if I copy some youtube tutorials, which seems to work like a charm.

The button in the form sends me to: http://localhost:8080/IUBHQuiz/login

Can you tell me whats wrong? I am going nuts.

login.java

package com.example.IUBHQuiz;
import java.io.*;
import javax.servlet.*;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.sql.*;
@WebServlet("/login")
public class login extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
String email = request.getParameter("fmail");
String pass = request.getParameter("fpw");
if(email.equals("j") && pass.equals("j"))
{
RequestDispatcher rs = request.getRequestDispatcher("/main.jsp");
rs.forward(request, response);
}
else
{
out.println("Username or Password incorrect");
RequestDispatcher rs = request.getRequestDispatcher("/index.jsp");
rs.include(request, response);
}
out.close();
}

index.jsp

<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
<title>IUBH Quiz</title>
<link href="./resources/css/style.css" rel="stylesheet">
</head>
<body>
<div class="main">
<div class="image-container">
<img src="./resources/images/logo.png" alt="Logo">
</div>
<div class="Login">
<h1>Willkommen beim IUBH-Quiz!</h1>
<form action="login" method="post">
E-Mail:<input type="text" id="fmail" name="fmail"><br><br>
Passwort: <input type="password" id="fpw" name="fpw"><br><br>
<input type="submit" value="Log In" class="button">
</form>
</div>
<div class="Links">
<a href="#">Passwort vergessen</a>
<a href="#">Registrieren</a>
</div>
</div>
</body>
</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
</web-app>

In Java web development with Tomcat, it’s very often that you get HTTP 404 error like this:

The error code is HTTP 404 (not found) and the description is:

The origin server did not find a current representation for the target resource or is not willing to disclose that one exists.

This error means the server could not find the requested resource (JSP, HTML, images…) and returns HTTP status code 404. Most of the time, you can fix this error by correcting the URL. However, sometimes it’s not easy like that, making it is an annoying error.

Here I suggest some possible reasons and how to fix the error HTTP 404 in Java web development with Tomcat.

1. The URL is not handled by any Java servlets

You need to check URL mapping in your servlet classes to make sure the requested URL is actually handled by a servlet. For example:

@WebServlet("/view_book")
public class ViewBookServlet extends HttpServlet {
...
}

This servlet handles the URL /view_book. If the request URL is /view_books the server will raise HTTP 404 error. You can fix by either correcting the URL or correcting the URL mapping in the @WebServlet annotation.

In older Java web application, you have to check the web deployment descriptor file web.xml because a Java servlet can be mapped to URL via XML like this:

<servlet-mapping>
    <servlet-name>ViewBookServlet</servlet-name>
    <url-pattern>/view_book</url-pattern>
</servlet-mapping>

2. Java servlet forwarding to a resource that does not exist

In this case, the requested URL is handled by a Java servlet, but code in the servlet forwards to a resource (JSP, HTML…) which does not exist, as shown in the following screenshot:

The code in the servlet class would look like this:

String registerForm = "frontend/registerform.jsp";
RequestDispatcher dispatcher = request.getRequestDispatcher(registerForm);
dispatcher.forward(request, response);

You can fix by correcting the forward path in the servlet, and make sure that the forwarded resource does actually exist in the given path.

3. URL is case-sensitive

Note that Tomcat treats URL as case-sensitive, for instance /Register is different than /register. So you need to check and use correct case for the letters in request URL.

Also pay attention to the webapp name in the URL, for instance http://localhost:8080/BookstoreWebsite/ is different than http://localhost:8080/BookStoreWebsite/

TIP: in Eclipse, you can right click on the project, then click Run As > Run on Server, the IDE will always use the correct name of the web application.

Finally, you should not let the user see the raw HTTP 404 error page rendered by the server. Instead, you should design your own user-friendly 404 error page – follow this tutorial: How to Handle Error for Java web applications.

You can also watch the video version below:

Other Java Servlet Tutorials:

• Java Servlet Quick Start for beginners (XML)
• Java Servlet for beginners (annotations)
• Java Servlet and JSP Hello World Tutorial with Eclipse, Maven and Apache Tomcat
• Handling HTML form data with Java Servlet
• Java File Download Servlet Example

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