Step-By-Step Implementation of @RequestMapping annotation

For this article, we’ll be using the following tools:

Java 8 or higher
Java IDE like Eclipse, IntelliJ, and VS code (We’ll be using IntelliJ)
POSTMAN for testing Request Mappings
Dependency: Spring Web Starter

Step-1: Create a starter file and extract it

Go to Spring Initializr and create a starter file having a single dependency – Spring Web. Download and extract it into your local folder and open it in your favorite IDE.

pom.xml File:

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>3.2.0</version> 
        <relativePath/> <!-- lookup parent from repository -->
    </parent> 
    <groupId>com.w3wiki</groupId> 
    <artifactId>RequestMappingExample</artifactId> 
    <version>0.0.1-SNAPSHOT</version> 
    <name>RequestMappingExample</name> 
    <description>Request Mapping Example</description> 
    <properties> 
        <java.version>17</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-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> 

Step-2: Define a Controller

Create a new package for containing all the controllers that we will be adding in our application under the src/main/java/package_name/Controllers
Add a new TestController inside Controllers Package for defining Request Mappings. Your final directory structure would look something like this :

Step-4: Define URL Templates inside the controller

Annotate the Controller with @Controller to signify that this class is a controller that has some URL templates defined inside it and @RequestMapping on the controller as well as the methods to specify which URL path will give what output.

Below is the code Implementation of Controller:

Java

import org.springframework.stereotype.Controller; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.ResponseBody; 
  
import java.util.ArrayList; 
import java.util.List; 
  
// Controller class 
@Controller
@ResponseBody
@RequestMapping("/test") 
public class TestController { 
  
    // URL Path - 1 
    // Returns a String 
    @RequestMapping("/hello") 
    public String sayHello() { 
        System.out.println("dsvsdvdsvs"); 
        return "Hello Geek!"; 
    } 
  
    // URL Path - 2 
    // Returns a String 
    @RequestMapping("/sport") 
    public String doSomeSport() { 
        return "Run 5 kilometers today!"; 
    } 
  
    // URL Path - 3 
    // Returns a List 
    @RequestMapping("/today/tasks") 
    public List<String> todaysTasks() { 
  
        List<String> myTasks = new ArrayList<String>(); 
        myTasks.add("Write 5 articles on w3wiki Today"); 
        myTasks.add("Run 5 kilometers"); 
        myTasks.add("Do Laundry"); 
  
        return myTasks; 
    } 
} 

Explanation of the above Program:

We’ve defined multiple end points using @RequestMapping which can be accessed at following URLs :

http://localhost:8080/test/hello
http://localhost:8080/test/sport
http://localhost:8080/test/today/tasks

Spring Boot – @Requestmapping

Spring Boot is the most popular framework of Java for building enterprise-level web applications and back-ends. Spring Boot has a handful of features that support quicker and more efficient web app development. Some of them are Auto-configuration, Embedded Server, opinionated defaults, and Annotation Support. In this article, we’ll be exploring the core annotation of Spring Boot – @RequestMapping which is part of the set of annotations that Spring Boot employs for defining URL endpoints and REST APIs.

Tags:

#Geeks Premier League 2023 #Java-Spring-Boot #Advance Java #Geeks Premier League #Java #Java

@RequestMapping

Annotations used: