Generate QRCode with Spring Data JPA in Spring MVC Framework

package com.demo;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    public class SpringMVCFramework {
    
        public static void main(String[] args) {
            SpringApplication.run(SpringMVCFramework.class, args);
        }
    }

package com.demo.controllers;

import java.io.OutputStream;
import javax.servlet.http.HttpServletResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import com.demo.helpers.ZXingHelper;
import com.demo.services.ProductService;

@Controller
@RequestMapping("product")
public class ProductController {

    @Autowired
    private ProductService productService;

    @RequestMapping(method = RequestMethod.GET)
    public String index(ModelMap modelMap) {
        modelMap.put("products", productService.findAll());
        return "product/index";
    }

    @RequestMapping(value = "qrcode/{id}", method = RequestMethod.GET)
    public void qrcode(@PathVariable("id") String id, HttpServletResponse response) throws Exception {
        response.setContentType("image/png");
        OutputStream outputStream = response.getOutputStream();
        outputStream.write(ZXingHelper.getQRCodeImage(id, 200, 200));
        outputStream.flush();
        outputStream.close();
    }

}

package com.demo.entities;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "product")
public class Product {

    @Id
    private String id;
    private String name;
    private double price;
    private int quantity;
    private boolean status;

    public String getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public int getQuantity() {
        return quantity;
    }

    public void setQuantity(int quantity) {
        this.quantity = quantity;
    }

    public boolean isStatus() {
        return status;
    }

    public void setStatus(boolean status) {
        this.status = status;
    }

}

package com.demo.repositories;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
import com.demo.entities.Product;

@Repository("productRepository")
public interface ProductRepository extends CrudRepository<Product, String> {
}

package com.demo.services;

import com.demo.entities.Product;

public interface ProductService {

    public Iterable<Product> findAll();

}

package com.demo.services;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.demo.entities.Product;
import com.demo.repositories.ProductRepository;

@Service("productService")
public class ProductServiceImpl implements ProductService {

    @Autowired
    private ProductRepository productRepository;

    @Override
    public Iterable<Product> findAll() {
        return productRepository.findAll();
    }

}

package com.demo.helpers;

import java.io.ByteArrayOutputStream;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;

public class ZXingHelper {

    public static byte[] getQRCodeImage(String text, int width, int height) {
        try {
            QRCodeWriter qrCodeWriter = new QRCodeWriter();
            BitMatrix bitMatrix = qrCodeWriter.encode(text, BarcodeFormat.QR_CODE, width, height);
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            MatrixToImageWriter.writeToStream(bitMatrix, "png", byteArrayOutputStream);
            return byteArrayOutputStream.toByteArray();
        } catch (Exception e) {
            return null;
        }
    }

}

spring.mvc.view.prefix = /WEB-INF/views/
spring.mvc.view.suffix = .jsp
spring.mvc.static-path-pattern=/resources/**

spring.datasource.url=jdbc:mysql://localhost:3306/learn_spring_mvc_with_real_apps
spring.datasource.username=root
spring.datasource.password=123456

server.port=9596

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>QR Code</title>
</head>
<body>

    <h3>Product List</h3>
    <table border="1" cellpadding="2" cellspacing="2">
        <tr>
            <th>Id</th>
            <th>Name</th>
            <th>Price</th>
            <th>Quantity</th>
            <th>Status</th>
            <th>BarCode</th>
        </tr>
        <c:forEach var="product" items="${products }">
            <tr>
                <td>${product.id }</td>
                <td>${product.name }</td>
                <td>${product.price }</td>
                <td>${product.quantity }</td>
                <td>${product.status }</td>
                <td>
                    <img src="${pageContext.request.contextPath }/product/qrcode/${product.id }" width="100" height="100">
                </td>
            </tr>
        </c:forEach>
    </table>

</body>
</html>

<?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
                        http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.demo</groupId>
    <artifactId>LearnSpringMVCWithRealApps</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>LearnSpringMVCWithRealApps</name>
    <description>Learn Spring MVC with Real Apps</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.5.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- JSTL tag lib -->
        <dependency>
            <groupId>javax.servlet.jsp.jstl</groupId>
            <artifactId>javax.servlet.jsp.jstl-api</artifactId>
            <version>1.2.1</version>
        </dependency>

        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>1.1.2</version>
        </dependency>

        <!-- Tomcat for JSP rendering -->
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>core</artifactId>
            <version>3.3.3</version>
        </dependency>

        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>javase</artifactId>
            <version>3.3.3</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-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>