# ResponseEntity example

Paul Tomoiu

●

Basics,

Spring,

ResponseEntity

●

Published 2024-11-15

This tutorial give you an example of using ResponseEntity.

Info

ResponseEntity is specific to Spring Framework, not just Spring Boot, though it is commonly used in Spring Boot applications as well.
used when you need to control the HTTP response sent back to the client (the status code, the headers, the body format).
ResponseEntity can return both JSON and XML responses (by default, Spring will use JSON).

Here we have an example:

DemoApplication.java
package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {
	public static void main(String[] args) {
		SpringApplication.run(DemoApplication.class, args);
	}
}

Emp.java
package com.example.demo.model;

public class Emp {
    private String id;
    private String nume;

    public Emp(String id, String nume) {
        this.id = id;
        this.nume = nume;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getNume() {
        return nume;
    }

    public void setNume(String nume) {
        this.nume = nume;
    }
}

EmpDto.java
package com.example.demo.dto;

public class EmpDto {
    private String empId;
    private String name;

    public EmpDto() { }

    public String getEmpId() {
        return empId;
    }

    public void setEmpId(String empId) {
        this.empId = empId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

MyController.java
package com.example.demo.controler;

import com.example.demo.dto.EmpDto;
import com.example.demo.model.Emp;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import com.example.demo.service.MyService;

import java.util.Optional;

@RestController
@RequestMapping()
public class MyController {

    private final MyService myService;

    public MyController(MyService myService) {
        this.myService = myService;
    }

    @GetMapping ("/view")
    public ResponseEntity<Emp> view(@RequestParam("id") String id) {

        Optional<Emp> response = myService.view(id);

        // Create HttpHeaders object
        HttpHeaders headers = new HttpHeaders();
        headers.add("X-Custom-Header", "ABCD");

        if (response.isEmpty()){
            return ResponseEntity
                    .status(HttpStatus.NOT_FOUND)
                    .body(null);
        }

        return ResponseEntity
                .status(HttpStatus.OK)
                .headers(headers)
                .body(response.get());
    }

    @PostMapping ("/add/{id}")
    public ResponseEntity<Void> view(@PathVariable String id,
                                     @RequestBody EmpDto empDto   ) {

        myService.add(id, empDto);

        return ResponseEntity
                .status(HttpStatus.OK)
                .body(null);
    }
}

MyService.java
package com.example.demo.service;

import com.example.demo.dto.EmpDto;
import com.example.demo.model.Emp;
import org.springframework.stereotype.Service;

import java.util.HashMap;
import java.util.Map;
import java.util.Optional;

@Service
public class MyService {

    private final Map<String, Emp> hashMap = new HashMap();

    public Optional<Emp> view(String id){
        return Optional.ofNullable(hashMap.get(id));
    }

    public void add(String id, EmpDto empDto){
        Emp emp = new Emp(empDto.getEmpId(), empDto.getName());
        hashMap.put(id, emp);
    }
}