Can't access REST Controller with Spring Boot autoconfiguration

Question

I am trying to create a simple REST service with Spring Boot following this tutorial. The "Hello World" html file from the webapp folder (index.html) is opening on http://localhost:8080/my-rest-app/ (I created a Maven-Web-App because I want to have a "Welcome Page" for the Service). But if I try to access the REST service on http://localhost:8080/my-rest-app/user I get a 404 message.

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>service</groupId>
    <artifactId>my-rest-app</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>my-rest-app</name>

    <properties>
        <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

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

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

</project>

Application.java:

package service.my.rest.app;

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

@SpringBootApplication
//@ComponentScan({"service.my.rest.app", "service.my.rest.app.controller"})
//@ComponentScan(basePackageClasses = UserController.class)
public class Application {

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

}

UserController.java:

package service.my.rest.app.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/user")
public class UserController {

    @RequestMapping(method = RequestMethod.GET)
    public String getUser() {
        return "Hello";
    }

}

What am I missing? Is the URL to the service wrong? I read somewhere that the context path of the Spring Boot REST service is always /, that would meant that I have to access the service over http://localhost:8080/my-rest-app/ but this does not working ether (without index.html). Changing the context path in the application.properties with server.contextPath=/my-rest-app and server.port=8080 also didn't help.

Is there a specific reason you're using war packaging instead of just a jar? — chrylis -cautiouslyoptimistic-, Oct 30 '16 at 07:48
Remove the `@RequestMapping(method = RequestMethod.GET)` from `getUser()` method. It'll invoke it via get method without the annotation + you're not specifiying a value in it. — Moshe Arad, Oct 30 '16 at 08:19
@chrylis I need to run the REST service on a Tomcat along with a normal webpage. Therefore the html files and the service are in the same war package. Actually I did not choose. Netbeans did the packaging and the Deploying on the server. — deve, Oct 30 '16 at 08:45
Spring Boot will happily serve HTML and JSON, even from the exact same URL if desired. There's no need to use an external container. — chrylis -cautiouslyoptimistic-, Oct 30 '16 at 08:55

score 4 · Accepted Answer · edited May 23 '17 at 10:27

The problem was the build and deploy process. Thank you @chrylis for the hint.

package service.my.rest.app;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.support.SpringBootServletInitializer;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan({"service.my.rest.app"})
public class Application extends SpringBootServletInitializer {

    private static Class<Application> application = Application.class;

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

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        return builder.sources(application);
    }

}

I had to extend my App to build and deploy a war file, because Spring Boot is actually designed to produce a jar.

Mine issue was component scan not having the correct package as well. — Ajay Menon, Jul 20 '21 at 12:37

score 0 · Answer 2 · answered Sep 07 '20 at 08:48

If your controller is into an external module you can provvide whitch componet autoconfigure by filling file: src/main/resources/MATA_INF/sping.factories

if i.e your controller is:

public ResponseEntity<?> execCommand(ComandoStr msg) {
@RequestMapping(value = "/api/exec")
@RestController
public class ExecController {

@PostMapping(value = "command")
public ResponseEntity<?> execCommand(ComandoStr msg) {
   ...
}

}

in sping.factories you need to add entry

imp.macchina.webapi.ExecController

then the controller get registered

Can't access REST Controller with Spring Boot autoconfiguration

2 Answers2