creating spring rest services without using spring boot

78
votes

I've followed the Getting Started tutorial on spring.io for building REEST services https://spring.io/guides/gs/rest-service/. The problem is that this tutorial only explain how to produce a standalone running jar with tomcat embedded using spring boot.

Is there a way to create a project from scratch to produce a war to deploy for instance on an already existing tomcat instance?

PS: I had found a previous thread Spring RESTful Service as a WAR instead of JAR in Tomcat on stackoverflow concerning the very same issue. The problem is that the accepted answers and suggestions doesn't exactly solve my problem, since I'm not looking for ways to modify the standalone-app spring boot project so that it works on an external tomcat container, but would like to find a 'cleaner' solution not involving spring boot at all. (I'm not exactly sure how to behave here, being still quite new at stackoverflow. I hope that opening a new question is the correct procedure).

2
javaspringresttomcat
Which parts of spring boot do you find "unclean"? Knowing which parts you are averse to would help in getting a better answer. – digitaljoel
Well, I spoke about a 'cleaner' solution only in relation to not having to create a project using some library (in this case boot, but could be anything else), then have to find some workaround to make the code work without it; I was not referring to some specific part of spring boot not being clean. – chrx
@digitaljoel I echo this question, boot is too stripped back. I am familar with maven, tomcat etc - I don't want to deploy a jar and want as minimal pom as possible (dependent on as few plugins as possible). I find it almost impossible to find the few jars I need for DI and MVC annotations (and possibly spring data), with the latest versions. – NimChimpsky
Spring Boot brings in alot of dependacies. Alot. And in some people's opinions, way too much. – granadaCoder
Any new framework like spring boot ideally should reduce the complexity.. I am amused why they introduced additional complexity.. – Stunner

2 Answers

68
votes

You don't need Spring Boot to create a rest controller.

Please follow the spring framework documentation on how to setup MVC https://docs.spring.io/spring/docs/current/spring-framework-reference/web.html#spring-web

The MVC setup (the DispatcherServlet) depends on your spring version, you can either use xml or you can setup programmatically: https://docs.spring.io/spring/docs/current/spring-framework-reference/web.html#mvc-servlet

Once this is setup, you can add a rest controller to your application. Note that a rest controller (the @RestController annotation) is a stereotype annotation that combines @ResponseBody and @Controller, in other words the Controller returns an object in the response body instead of returning a view.

This is a perfect example explaining what I said above: http://www.programming-free.com/2014/01/spring-mvc-40-restful-web-services.html

15
votes

Here is another example:

Directory Layout:

.
├── ./pom.xml
└── ./src
    └── ./src/main
        ├── ./src/main/java
        │   └── ./src/main/java/biz
        │       └── ./src/main/java/biz/tugay
        │           └── ./src/main/java/biz/tugay/restfulspring
        │               └── ./src/main/java/biz/tugay/restfulspring/config
        │                   ├── ./src/main/java/biz/tugay/restfulspring/config/RestfulHello.java
        │                   └── ./src/main/java/biz/tugay/restfulspring/config/WebAppInitalizer.java
        └── ./src/main/webapp
            └── ./src/main/webapp/WEB-INF
                └── ./src/main/webapp/WEB-INF/web.xml

pom.xml

<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/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <groupId>biz.tugay</groupId>
    <artifactId>restfulSpring</artifactId>

    <packaging>war</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>restfulSpring Maven Webapp</name>

    <url>http://maven.apache.org</url>

    <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.3.16.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.3.16.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.3.16.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.3.16.RELEASE</version>
        </dependency>
    </dependencies>

    <build>
        <finalName>restfulSpring</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.eclipse.jetty</groupId>
                <artifactId>jetty-maven-plugin</artifactId>
                <version>9.2.1.v20140609</version>
            </plugin>
        </plugins>
    </build>

</project>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                             http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         version="3.0">
</web-app>

WebAppInitalizer.java

package biz.tugay.restfulspring.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

@Configuration
@EnableWebMvc
@ComponentScan("biz.tugay.restfulspring")
public class WebAppInitalizer extends AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/*"};
    }

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[]{WebAppInitalizer.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[0];
    }
}

RestfulHello.java

package biz.tugay.restfulspring.config;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping(value = "/")
public class RestfulHello {

    @RequestMapping(value = "hello")
    public ResponseEntity<String> sayHello() {
        final HttpHeaders httpHeaders= new HttpHeaders();
        httpHeaders.setContentType(MediaType.APPLICATION_JSON);
        return new ResponseEntity<String>("{\"msg\": \"Hello World\"}", httpHeaders, HttpStatus.OK);
    }
}

Build and run:

mvn clean install
mvn jetty:start

Test:

> GET /hello HTTP/1.1
> Host: localhost:8080
> User-Agent: insomnia/5.15.0
> Accept: */*
< HTTP/1.1 200 OK
< Date: Fri, 27 Apr 2018 00:06:07 GMT
< Content-Type: application/json
< Content-Length: 22
< Server: Jetty(9.2.1.v20140609)

Content received:

{
    "msg": "Hello World"
}