Spring Boot Rest API Generate QR Code
Tags: zxing generate QR code Rest API QR code Spring Boot QR Code Java QR Code
This Java Spring Boot tutorial to show you how to develop a Spring Boot Restful API which generate QR code image using ZXing library.
Table of contents
- Create New Spring Boot Restful API Project
- Add ZXing dependencies to the Project
- Implement QR Code Service Class
- Implement Controller Class
- Complete Application Source Code
- Run Application
- Download The Source Code
Create New Spring Boot Restful API Project
Open IntelliJ IDEA, select the menu File > New > Project. (or click on New Project button at IntelliJ Welcome dialog)
On the New Project dialog, select Spring Initializr and click Next button.
On the Spring initializr Project Settings dialog input the new project information as below and click Next button.
- Group: dev.simplesolution
- Artifact: spring-boot-rest-qr-code
- Type: Gradle
- Version: 1.0.0
- Name: spring-boot-rest-qr-code
- Description: Spring Boot Restful API Generate QR Code
- Package: dev.simplesolution.restqrcode
On the Dependencies dialog, select below dependencies and click Next button.
- Spring Web
Select the location for your project and click Finish button to create new Spring Boot project.
Add ZXing dependencies to the Project
To generate the QR code image we use the ZXing library.
To use ZXing library in the Gradle project, add the following dependency to the build.gradle file
implementation group: 'com.google.zxing', name: 'core', version: '3.4.1'
implementation group: 'com.google.zxing', name: 'javase', version: '3.4.1'If you are using Maven build, add the following dependency to the pom.xml file.
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>core</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>javase</artifactId>
<version>3.4.1</version>
</dependency>Implement QR Code Service Class
At this step we implement a service class to generate QR code image as an array of bytes.
Create a new Java package named dev.simplesolution.restqrcode.service and adding new Java interface named QrCodeService as Java code below.
java/dev/simplesolution/restqrcode/service/QrCodeService.java
package dev.simplesolution.restqrcode.service;
public interface QrCodeService {
byte[] generateQrCode(String qrCodeContent, int width, int height);
}Create a new Java package named dev.simplesolution.restqrcode.service.impl, and implement a new Java class named QrCodeServiceImpl as below.
java/dev/simplesolution/restqrcode/service/impl/QrCodeServiceImpl.java
package dev.simplesolution.restqrcode.service.impl;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.WriterException;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import dev.simplesolution.restqrcode.service.QrCodeService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
@Service
public class QrCodeServiceImpl implements QrCodeService {
private Logger logger = LoggerFactory.getLogger(QrCodeServiceImpl.class);
@Override
public byte[] generateQrCode(String qrCodeContent, int width, int height) {
try {
QRCodeWriter qrCodeWriter = new QRCodeWriter();
BitMatrix bitMatrix = qrCodeWriter.encode(qrCodeContent, BarcodeFormat.QR_CODE, width, height);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
MatrixToImageWriter.writeToStream(bitMatrix, "PNG", byteArrayOutputStream);
return byteArrayOutputStream.toByteArray();
} catch (WriterException e) {
logger.error(e.getMessage(), e);
} catch (IOException e) {
logger.error(e.getMessage(), e);
}
return null;
}
}Implement Controller Class
At this step we implement a controller to expose a Restful API to allow download the QR image.
Create a new Java package named dev.simplesolution.restqrcode.controller, and implement a controller class named QrCodeController as following Java code.
java/dev/simplesolution/restqrcode/controller/QrCodeController.java
package dev.simplesolution.restqrcode.controller;
import dev.simplesolution.restqrcode.service.QrCodeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class QrCodeController {
private static final int WIDTH = 500;
private static final int HEIGHT = 500;
@Autowired
private QrCodeService qrCodeService;
@GetMapping("/generate-qr-code")
public ResponseEntity<byte[]> getQrCode() {
String contentToGenerateQrCode = "Simple Solution";
byte[] qrCode = qrCodeService.generateQrCode(contentToGenerateQrCode, WIDTH, HEIGHT);
return ResponseEntity.ok().contentType(MediaType.IMAGE_PNG).body(qrCode);
}
}Complete Application Source Code
At this step we already finished the implementation of the Restful API to generate QR code as following project structure.
Run Application
Execute the Java Spring Boot application, and open the link http://localhost:8080/generate-qr-code on your browser to get the QR code as the following screenshot.
Download The Source Code
The source code in this article can be found at: github.com/simplesolutiondev/spring-boot-rest-qr-code
or clone at:
git clone https://github.com/simplesolutiondev/spring-boot-rest-qr-code.git
or download at:
Happy Coding 😊
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