How to Create Spring RESTful API without using Spring Boot

Post author:Chinna
Post published:February 1, 2020
Post category:Spring
Post comments:7 Comments

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Most Spring Tutorials available online teach you how to create/secure a Rest API with Spring boot. However, sometimes there will be specific use cases where you will need to create/secure REST API without using spring boot. This tutorial aims to help you create a REST application without using Spring Boot at all.

Note: If you don’t wanna use even the Spring framework, then you can read on how to create REST API in Java without Spring.

What you’ll build

A Spring REST service which will simply accept a name as a path variable in the request and say hello with that name in the response

What you’ll need

Spring Tool Suite 4
JDK 11
MySQL Server 8
Maven

Tech Stack

Spring 5
JDK 11
Log4j 2

Bootstrap your application

Let’s bootstrap the application by creating a maven project in STS

Project Dependencies

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>com.javachinna</groupId>
  <artifactId>spring-rest-jwt-demo</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>spring-rest-jwt-demo Maven Webapp</name>
  <url>http://maven.apache.org</url>
  	<properties>
		<java-version>11</java-version>
		<spring.version>5.2.3.RELEASE</spring.version>
		<hibernate.version>5.4.1.Final</hibernate.version>
	</properties>
	<dependencies>
		<!-- Spring Web MVC -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<!-- Required for converting JSON data to Java object and vice versa -->
		<dependency>
			<groupId>com.fasterxml.jackson.core</groupId>
			<artifactId>jackson-databind</artifactId>
			<version>2.9.10.1</version>
		</dependency>
		<!-- Servlet API -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>javax.servlet-api</artifactId>
			<version>3.0.1</version>
			<scope>provided</scope>
		</dependency>
		<dependency>
			<groupId>log4j</groupId>
			<artifactId>log4j</artifactId>
			<version>1.2.17</version>
		</dependency>
	</dependencies>
	<build>
		<finalName>SpringRestJwt</finalName>
		<pluginManagement>
			<plugins>
				<plugin>
					<groupId>org.apache.maven.plugins</groupId>
					<artifactId>maven-compiler-plugin</artifactId>
					<version>2.3.2</version>
					<configuration>
						<source>${java-version}</source>
						<target>${java-version}</target>
					</configuration>
				</plugin>
				<plugin>
					<groupId>org.apache.maven.plugins</groupId>
					<artifactId>maven-war-plugin</artifactId>
					<version>3.2.3</version>
					<configuration>
						<warSourceDirectory>src/main/webapp</warSourceDirectory>
						<warName>SpringRestJwt</warName>
					</configuration>
				</plugin>
			</plugins>
		</pluginManagement>
	</build>
</project>

Spring Configuration

SpringWebInitializer.java

WebApplicationContext can be configured using web.xml or Java-based configuration as shown below

SpringWebInitializer class extends Spring’s AbstractAnnotationConfigDispatcherServletInitializer to configure the WebApplicationContext.

package com.javachinna.config;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class SpringWebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

	@Override
	protected Class[] getServletConfigClasses() {
		return new Class[] { WebConfig.class };
	}

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

	@Override
	protected Class[] getRootConfigClasses() {
		return new Class[] {};
	}
}

WebConfig.java

WebConfig class implements WebMvcConfigurer to configure the Jackson message converters

@EnableWebMvc annotation is used to enable Spring MVC support

@ComponentScan annotation is used with the @Configuration annotation to tell Spring the packages to scan for annotated components.

package com.javachinna.config;

import java.util.List;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@EnableWebMvc
@Configuration
@ComponentScan("com.javachinna")
public class WebConfig implements WebMvcConfigurer {

	@Override
	public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
		converters.add(new MappingJackson2HttpMessageConverter());
	}
}

Create REST Controller

GreetController.java

Controller class for exposing a GET REST API

package com.javachinna.controller;

import org.apache.log4j.Logger;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class GreetController {

	private Logger logger = Logger.getLogger(GreetController.class);

	@GetMapping("/greet/{name}")
	public String greet(@PathVariable String name, ModelMap model) {
		String greet = "Hello!!! " + name + " How are You?";
		logger.info(greet);
		return greet;
	}
}

Log4J Configuration

log4j.properties

# Root logger option
log4j.rootLogger=DEBUG, stdout, file
# Redirect log messages to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

# Redirect log messages to a log file
log4j.appender.file=org.apache.log4j.RollingFileAppender
#outputs to Tomcat home
log4j.appender.file.File=${catalina.home}/logs/myapp.log
log4j.appender.file.MaxFileSize=5MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

Build Application

Run mvn clean install command to clean and build the war file

Deploy Application

Deploy the generated war file in a server like tomcat and hit the URL http://localhost:8080/SpringRestJwt/greet/Chinna

Conclusion

That’s all folks. In this article, we have developed a simple Spring REST service without using Spring Boot. Thank you for reading