Spring Boot Whitelabel Error page (type=Not Found, status=404)

Question

Good afternoon, I'm starting spring studies, I'm following a tutorial the same way: but it returns an error:

Folder structure:

The strange thing is: If I insert the "EventoController.java" into br.com.SpringApp.SpringApp, it works correctly.

package br.com.SpringApp.SpringApp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringAppApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringAppApplication.class, args);
    }
}

.

package br.com.SpringApp.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class EventoController {

    @RequestMapping("/cadastroEvento")
    public String form() {      
        return "evento/formEvento"; 
    }

}

As requested, I'm adding pom.xml

   <?xml version="1.0" encoding="UTF-8"?>
   <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>br.com.SpringApp</groupId>
    <artifactId>SpringApp</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>SpringApp</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


   </project>

Can someone tell me where I'm wrong, please?

Answer 1

Make sure that your main class is in a root package above other classes.

When you run a Spring Boot Application, (ie a class annotated with @SpringBootApplication), Spring will only scan the classes below your main class package.

So your declaration goes like this

package br.com.SpringApp.SpringApp; inside this main class ie SpringAppApplication

package br.com.SpringApp.SpringApp.controller; name of your controllers ie EventoController & indexControllers

package br.com.SpringApp.SpringApp.model; name of your models ie Evento

After This clean your project and re-run spring boot application;

Answer 2

Solution: If you are using @Controller over the Controller class then it will be treated as a MVC controller class. But if you want a special controller used in RESTFul web services then you to use @Controller along with @ResponseBody annotation or you can directly use @RestController over the Controller class. It worked for me as I was getting the same error while creating SpringBoot project with RestFul webservices.

package br.com.SpringApp.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class EventoController {

    @RequestMapping("/cadastroEvento")
    @ResponseBody
    public String form() {      
        return "evento/formEvento"; 
    }

}

or:

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@RestController
public class EventoController {

    @RequestMapping("/cadastroEvento")
    public String form() {      
        return "evento/formEvento"; 
    }

}

Answer 3

verify that you have the correct thymeleaf dependency within your pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>      
</dependency>

Answer 4

As answered by Deepak, main class should be in a root package above other packages. But if you don't want to do this, you can use:

@SpringBootApplication(scanBasePackages = {"com.other.packages","com.other"})
public class SpringAppApplication {
.....
}

Answer 5

As a beginner to the SpringBoot, this error can be happened to anyone at least one time, because for a few reasons.

1. The Application class (eg: SpringAppApplication.java) should be at the root level, as well as the controller classes can be placed under the same level or maybe in a subdirectory. This application class should be denoted using @SpringBootApplication or extends SpringBootApplication
2. You may miss @RestController annotation at top of the controller class.
3. Or can be missed the mapping annotation.( @PostMapping("/save") or @GetMapping("/id") etc.)
4. finally just check whether you are entering the correct request mapping address(URL) you may miss a slash or @RequestMapping("/customer") (if the annotation available in your controller class) or spellings error in the URL.

Answer 6

I mistakenly give name parameter in my GetMapping and PostMapping

@GetMapping(name: "/all")//wrong code

Actually, you need to specify the path directly

@GetMapping("/all") //correct code - remove name 

Hope this mistake may help anyone in future!

Answer 7

The other classes should be on same level or under it of the main class. Also, use @Controller or @RestController

@Controller
public class PrintHello {

    @RequestMapping("/hello")
    @ResponseBody
    public String helloFunction() {      
        return "hello"; 
    }

}

Answer 8

In case someone sees this error: Check if you saved all of your files.

In my case, it was solved by saving all files.