How to Creating a Spring Boot Project and Creating a Hello world Program ? (Spring Boot #02)

Re-requisites:

• Java JDK 1.8
• Spring Tool Suite IDE
• Internet Connectivity

 

This Article describes how to creating a new Spring-boot project and making a simple Hello World program with Spring Tool Suite. Spring Tool suite is a great IDE for developing spring based applications. It is developed by Pivotal (Spring) based on Eclipse. For creating a fresh Spring Boot project, there are several ways. 

1. Via -> Spring Initializr (https://start.spring.io/)
2. Via->  STS -> Spring Starter Project
3. Via -> STS -> Import Spring getting started contents

You are able to do it by selecting any of above options. For this demonstration, I select the second option “Spring starter project”. No matter you can do it, selecting any of above options. Let’s go.

Open your STS and go to this path.

File ->> New ->>  Spring Starter Project.

After that, You will find a window like below.

 

Screen1

Then, You should provide the details for filling the form. My project details are mentioned in Screen1. Type should be Maven. Because, We are going to build a maven based project. After filling, go next. Then you can select/change the spring boot version. You should select dependencies from here. For this simple demonstration, lets select ‘Spring Web’. This dependency is used for developing restful web services. 

Screen2

 

And also, You can add/remove/modify dependencies after creating the project on pom.xml file. In Maven, pom.xml handles project dependencies.  Lets click ‘next’ and click ‘finish’. Now You can see, The created project in left side of your STS IDE.

My 'Pom.xml' file contents are mentioned below.

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 https://maven.apache.org/xsd/maven-4.0.0.xsd">

       <modelVersion>4.0.0</modelVersion>

       <parent>

              <groupId>org.springframework.boot</groupId>

              <artifactId>spring-boot-starter-parent</artifactId>

              <version>2.2.6.RELEASE</version>

              <relativePath/> <!-- lookup parent from repository -->

       </parent>

       <groupId>com.claps</groupId>

       <artifactId>MyTestApp</artifactId>

       <version>0.0.1-SNAPSHOT</version>

       <name>MyTestApp</name>

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

       <properties>

              <java.version>1.8</java.version>

       </properties>

       <dependencies>

              <dependency>

                     <groupId>org.springframework.boot</groupId>

                     <artifactId>spring-boot-starter-web</artifactId>

              </dependency>

              <dependency>

                     <groupId>org.springframework.boot</groupId>

                     <artifactId>spring-boot-starter-web-services</artifactId>

              </dependency>

              <dependency>

                     <groupId>org.springframework.boot</groupId>

                     <artifactId>spring-boot-starter-test</artifactId>

                     <scope>test</scope>

                     <exclusions>

                           <exclusion>

                                  <groupId>org.junit.vintage</groupId>

                                  <artifactId>junit-vintage-engine</artifactId>

                           </exclusion>

                     </exclusions>

              </dependency>

       </dependencies>

       <build>

              <plugins>

                     <plugin>

                           <groupId>org.springframework.boot</groupId>

                           <artifactId>spring-boot-maven-plugin</artifactId>

                     </plugin>

              </plugins>

       </build>

</project>

If you do any change in pom.xml, update the maven project.

The way is, right click on the project -> Maven -> Update Project.

Now I am going to implement the Hello World Program. There are many ways to express this. I am going to do it using a controller class.

I created a controller main class ‘MyController’. To the MyController, I set the annotation -> @RestController

Then, Lets write a method for displaying “Hello world”. Refer the following code.

MyController.Java

package com.claps;

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

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

@RestController

public class MyController {

       //TestAPI

       @RequestMapping("/Hello")

       public String hello() {

              return "Hello world";

             

      

       }

      

}

In the above my code, @RequestMapping annotation explains how should be the URl end (context path). In this example it should be http://host:port/Hello 

Below codes is the main Java file of my project. It creates automatically when creating the project.

MyTestApplication.Java

package com.claps;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication

public class MyTestAppApplication {

       public static void main(String[] args) {

              SpringApplication.run(MyTestAppApplication.class, args);

       }

}

 

Run the Program:

Screen3 

Now, We have completed the work. Lets run the program

Right click on the project -> Run as -> Spring Boot App

Then The Program will start..

Screen4

According to terminal screen, the allocated port is 8080. Then My testing URI should be :

http://localhost:8080/Hello

Now It can be test in your web browser. Type the URI on the address bar and hit. Them You can see the response. Happy Coding !