Spring @ResponseBody Annotation Example
In this section we will learn about @ResponseBody Annotation.
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The @ResponseBody annotation is used at method level or method return type level.
The @ResponseBody constructs the response body as JSON or XML or other media type based on following points.
1. MessageConverter configured in the application.
2. Media-type configured by produces attribute in annotations @RequestMapping, @GetMapping etc.
3. Media-type configured by accept request header.
The @ResponseBody only configures body of response. To set response status code we use @ResponseStatus annotation at method level. If status code is not set explicitly, default status code is set to response. The @ResponseBody is used with @Controller annotation, the @ResponseBody is annotated at method level whereas @Controller is annotated at class level. If we use @RestController annotation, then @ResponseBody is not needed to use. This is because
@RestController = @Controller + @ResponseBody
Using @ResponseBody
The @ResponseBody can be used at method level as well as method return type level.
1. Find the code to use @ResponseBody at method level.
2. Find the code to use @ResponseBody at method return type level.
3. To produce JSON response body, we need to use produces attribute of @GetMapping and assign it application/json. Find the code that will produce JSON response body.
4. To produce XML response body, we need to use application/xml media-type.
The following example creates a Spring Boot web application that returns JSON and XML data to the client.
Project Directory
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>3.0.1</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.knf.dev.demo</groupId>
<artifactId>spring-responsebody-example</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>spring-responsebody-example</name>
<description>Demo project for Spring Boot</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>
User.java
package com.knf.dev.demo.dto;
public class User {
private String name;
private String email;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
UserController.java
package com.knf.dev.demo.controller;
import com.knf.dev.demo.dto.User;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import java.util.ArrayList;
import java.util.List;
@Controller
@RequestMapping("/api/v1")
public class UserController {
// @ResponseBody at method return type level.
@GetMapping(value = "/example1/users")
public @ResponseBody List<User> getUsersABC() {
User user1= new User();
user1.setEmail("user1@gmail.com");
user1.setName("John");
User user2= new User();
user2.setEmail("user2@gmail.com");
user2.setName("Sibin");
List<User> list = new ArrayList<>();
list.add(user1);
list.add(user2);
return list;
}
// @ResponseBody at method level
@GetMapping(value = "/example2/users")
@ResponseBody
@ResponseStatus(HttpStatus.OK)
public List<User> getUsersBCD() {
User user1= new User();
user1.setEmail("user1@gmail.com");
user1.setName("John");
User user2= new User();
user2.setEmail("user2@gmail.com");
user2.setName("Sibin");
List<User> list = new ArrayList<>();
list.add(user1);
list.add(user2);
return list;
}
}
Run Application - Application.java
mvn spring-boot:runTry to send a GET request to the /example1/users endpoint using Postman to test "@ResponseBody at method return type level"
