spring boot css having problem in rendering

Question

Im trying to convert my spring mvc project into spring boot. I converted all necessary files according to spring boot.There are no errors on console. But when i run my web app in browser my app run successfully but there are no css loading.I tried all solutions of stack overflow but nothing help.Please help me to sovle this problem.

OnlineshoppingApplication.java

    package net.kzn.onlineshopping;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ImportResource;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;

@SpringBootApplication
@EnableWebSecurity
@ImportResource({"classpath:/**/spring-security.xml"})
@ComponentScan(basePackages = {"net.kzn.onlineshopping.*","net.kzn.shoppingbackend.*"})

public class OnlineshoppingApplication {

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

AppConfig.java

            package net.kzn.onlineshopping.config;

        import java.util.Collections;

    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.ui.context.support.ResourceBundleThemeSource;
    import org.springframework.web.multipart.commons.CommonsMultipartResolver;
    import org.springframework.web.servlet.ViewResolver;
    import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
    import org.springframework.web.servlet.config.annotation.EnableWebMvc;
    import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
    import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
    import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
    import org.springframework.web.servlet.theme.CookieThemeResolver;
    import org.springframework.web.servlet.theme.ThemeChangeInterceptor;
    import org.springframework.web.servlet.view.InternalResourceViewResolver;
    import org.springframework.web.servlet.view.JstlView;
    import org.springframework.webflow.config.AbstractFlowConfiguration;
    import org.springframework.webflow.definition.registry.FlowDefinitionRegistry;
    import org.springframework.webflow.engine.builder.support.FlowBuilderServices;
    import org.springframework.webflow.executor.FlowExecutor;
    import org.springframework.webflow.mvc.builder.MvcViewFactoryCreator;
    import org.springframework.webflow.mvc.servlet.FlowHandlerMapping;

        @Configuration
        @EnableWebMvc
        @ComponentScan("net.kzn.onlineshopping")
        public class AppConfig extends AbstractFlowConfiguration implements WebMvcConfigurer {

               @Autowired
                private AppConfig AppConfig;


            public void addViewControllers(ViewControllerRegistry registry) {
                registry.addViewController("/").setViewName("index");
            }

            /** View resolver for JSP */
            @Bean
            public ViewResolver getViewResolver(){
                InternalResourceViewResolver resolver = new InternalResourceViewResolver();
                resolver.setViewClass(JstlView.class);
                resolver.setPrefix("/WEB-INF/views/");
                resolver.setSuffix(".jsp");
                return resolver;
            }

            /** Multipart file uploading configuratioin */
            @Bean(name = "multipartResolver")
            public CommonsMultipartResolver multipartResolver() {
                CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
                multipartResolver.setMaxUploadSize(100000);
                return multipartResolver;
            }


            // Static resource locations including themes
            @Override
            public void addResourceHandlers(ResourceHandlerRegistry registry) {
                    registry.addResourceHandler("/resources/**")
                    .addResourceLocations("/assets/")
                            .setCachePeriod(31556926);
            }

            /** BEGIN theme configuration */
            @Bean
            public ResourceBundleThemeSource themeSource(){
                ResourceBundleThemeSource themeSource = new ResourceBundleThemeSource();
                themeSource.setDefaultEncoding("UTF-8");
                themeSource.setBasenamePrefix("themes.");
                return themeSource;
            }

            @Bean
            public CookieThemeResolver themeResolver(){
                CookieThemeResolver resolver = new CookieThemeResolver();
                resolver.setDefaultThemeName("default");
                resolver.setCookieName("example-theme-cookie");
                return resolver;
            }

            @Bean
            public ThemeChangeInterceptor themeChangeInterceptor(){
                ThemeChangeInterceptor interceptor = new ThemeChangeInterceptor();
                interceptor.setParamName("theme");
                return interceptor;
            }

            @Override
            public void addInterceptors(InterceptorRegistry registry) {
                registry.addInterceptor(themeChangeInterceptor());
            }
            /** END theme configuration */

            @Bean
            public FlowDefinitionRegistry flowRegistry() {
                return getFlowDefinitionRegistryBuilder()
                        .setBasePath("/WEB-INF/views/flows")
                        .addFlowLocationPattern("/**/*-flow.xml")
                        .build();
                }

            @Bean
            public FlowExecutor flowExecutor() {
                return getFlowExecutorBuilder(flowRegistry()).build();
            }

            @Bean
            public FlowBuilderServices flowBuilderServices() {
                return getFlowBuilderServicesBuilder().setViewFactoryCreator(mvcViewFactoryCreator()).setDevelopmentMode(true).build();
            }

            @Bean
            public FlowHandlerMapping flowHandlerMapping() {
                FlowHandlerMapping handlerMapping = new FlowHandlerMapping();
                handlerMapping.setOrder(-1);
                handlerMapping.setFlowRegistry(this.AppConfig.flowRegistry());
                return handlerMapping;
            }

            @Bean
            public MvcViewFactoryCreator mvcViewFactoryCreator() {
                MvcViewFactoryCreator factoryCreator = new MvcViewFactoryCreator();
                factoryCreator.setViewResolvers(Collections.singletonList(this.AppConfig.getViewResolver()));
                factoryCreator.setUseSpringBeanBinding(true);
                return factoryCreator;
            }

            @Override
            public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
                configurer.enable();
            }
        }

web.xml

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
     http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
version="3.1">
<display-name>Archetype Created Web Application</display-name>

<!-- configuring front-controller -->
<servlet>
    <servlet-name>dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

    <!-- For throwing Exception -->
    <init-param>
        <param-name>throwExceptionIfNoHandlerFound</param-name>
        <param-value>true</param-value>
    </init-param>

    <multipart-config>
        <max-file-size>2097152</max-file-size>
        <max-request-size>4194304</max-request-size>
        <file-size-threshold>1048576</file-size-threshold>
    </multipart-config>
</servlet>

<servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

<!-- Spring security configuration -->
<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>
        /WEB-INF/spring-security.xml
    </param-value>
</context-param>

<filter>
    <filter-name>springSecurityFilterChain</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>

<filter-mapping>
    <filter-name>springSecurityFilterChain</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

PageController.java

        package net.kzn.onlineshopping.controller;

    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;

    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.security.core.Authentication;
    import org.springframework.security.core.context.SecurityContextHolder;
    import org.springframework.security.web.authentication.logout.SecurityContextLogoutHandler;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.servlet.ModelAndView;

    import net.kzn.onlineshopping.exception.ProductNotFoundException;
    import net.kzn.shoppingbackend.dao.CategoryDAO;
    import net.kzn.shoppingbackend.dao.ProductDAO;
    import net.kzn.shoppingbackend.dto.Category;
    import net.kzn.shoppingbackend.dto.Product;

    @Controller
    public class PageController {

        private static final Logger logger = LoggerFactory.getLogger(PageController.class);

        @Autowired
        private CategoryDAO categoryDAO;

        @Autowired
        private ProductDAO productDAO;

        @RequestMapping(value = { "/", "/home", "/index" })
        public ModelAndView index(@RequestParam(name = "logout", required = false) String logout) {
            ModelAndView mv = new ModelAndView("page");
            mv.addObject("title", "Home");

            logger.info("Inside PageController index method - INFO");
            logger.debug("Inside PageController index method - DEBUG");

            // passing the list of categories
            mv.addObject("categories", categoryDAO.list());

            if (logout != null) {
                mv.addObject("message", "You have successfully logged out!");
            }

            mv.addObject("userClickHome", true);
            return mv;
        }

        @RequestMapping(value = "/about")
        public ModelAndView about() {
            ModelAndView mv = new ModelAndView("page");
            mv.addObject("title", "About Us");
            mv.addObject("userClickAbout", true);
            return mv;
        }

        @RequestMapping(value = "/contact")
        public ModelAndView contact() {
            ModelAndView mv = new ModelAndView("page");
            mv.addObject("title", "Contact Us");
            mv.addObject("userClickContact", true);
            return mv;
        }

        /*
         * Methods to load all the products and based on category
         */

        @RequestMapping(value = "/show/all/products")
        public ModelAndView showAllProducts() {
            ModelAndView mv = new ModelAndView("page");
            mv.addObject("title", "All Products");

            // passing the list of categories
            mv.addObject("categories", categoryDAO.list());

            mv.addObject("userClickAllProducts", true);
            return mv;
        }

        @RequestMapping(value = "/show/category/{id}/products")
        public ModelAndView showCategoryProducts(@PathVariable("id") int id) {
            ModelAndView mv = new ModelAndView("page");

            // categoryDAO to fetch a single category
            Category category = null;

            category = categoryDAO.get(id);

            mv.addObject("title", category.getName());

            // passing the list of categories
            mv.addObject("categories", categoryDAO.list());

            // passing the single category object
            mv.addObject("category", category);

            mv.addObject("userClickCategoryProducts", true);
            return mv;
        }

        /*
         * Viewing a single product
         */

        @RequestMapping(value = "/show/{id}/product")
        public ModelAndView showSingleProduct(@PathVariable int id) throws ProductNotFoundException {

            ModelAndView mv = new ModelAndView("page");

            Product product = productDAO.get(id);

            if (product == null)
                throw new ProductNotFoundException();

            // update the view count
            product.setViews(product.getViews() + 1);
            productDAO.update(product);
            // ---------------------------

            mv.addObject("title", product.getName());
            mv.addObject("product", product);

            mv.addObject("userClickShowProduct", true);

            return mv;

        }

        @RequestMapping(value = "/membership")
        public ModelAndView register() {
            ModelAndView mv = new ModelAndView("page");

            logger.info("Page Controller membership called!");

            return mv;
        }

        @RequestMapping(value = "/login")
        public ModelAndView login(@RequestParam(name = "error", required = false) String error,
                @RequestParam(name = "logout", required = false) String logout) {
            ModelAndView mv = new ModelAndView("login");
            mv.addObject("title", "Login");
            if (error != null) {
                mv.addObject("message", "Username and Password is invalid!");
            }
            if (logout != null) {
                mv.addObject("logout", "You have logged out successfully!");
            }
            return mv;
        }

        @RequestMapping(value = "/logout")
        public String logout(HttpServletRequest request, HttpServletResponse response) {
            // Invalidates HTTP Session, then unbinds any objects bound to it.
            // Removes the authentication from securitycontext
            Authentication auth = SecurityContextHolder.getContext().getAuthentication();
            if (auth != null) {
                new SecurityContextLogoutHandler().logout(request, response, auth);
            }

            return "redirect:/login?logout";
        }

        @RequestMapping(value = "/access-denied")
        public ModelAndView accessDenied() {
            ModelAndView mv = new ModelAndView("error");
            mv.addObject("errorTitle", "Aha! Caught You.");
            mv.addObject("errorDescription", "You are not authorized to view this page!");
            mv.addObject("title", "403 Access Denied");
            return mv;
        }

        @RequestMapping(value = "/view/category/{id}/products")
        public ModelAndView viewProducts(@PathVariable("id") int id) {
            ModelAndView mv = new ModelAndView("page");
            // categoryDAO to fetch a single category
            Category category = null;

            category = categoryDAO.get(id);

            mv.addObject("title", category.getName());

            // passing the list of categories
            mv.addObject("viewproducts", productDAO.listActiveProductsByCategory(id));

            mv.addObject("userClickViewProducts", true);
            return mv;
        }


        @RequestMapping(value = "/search")
        public ModelAndView Search(@RequestParam(value = "searchTerm", required = false) String pSearchTerm,
                HttpServletRequest request, HttpServletResponse response) {
            ModelAndView mv = new ModelAndView("search");

            mv.addObject("searchTerm", pSearchTerm);
            mv.addObject("searchResult", productDAO.searchProductsByParam(pSearchTerm));

            mv.addObject("userClickSearch", true);

            return mv;
        }

    }

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

    <groupId>net.kzn</groupId>
    <artifactId>onlineshopping</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>onlineshopping</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.6.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>net.kzn</groupId>
            <artifactId>shoppingbackend</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

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

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </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>

        <!-- JSTL -->

        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/javax.servlet.jsp/javax.servlet.jsp-api -->
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.3.1</version>
            <scope>provided</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-taglibs -->
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-taglibs</artifactId>
            <version>5.0.9.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.1</version>
        </dependency>

        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <scope>provided</scope>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>

        <resources>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
            <resource>
                <directory>src/main/webapp</directory>
            </resource>
        </resources>
    </build>


</project>

page,jsp

    <%@ 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"%>
<%@taglib prefix="spring" uri="http://www.springframework.org/tags"%>

<spring:url var="css" value="/resources/css" />
<spring:url var="js" value="/resources/js" />
<spring:url var="images" value="/resources/images" />

<c:set var="contextRoot" value="${pageContext.request.contextPath}" />
<!DOCTYPE html>
<html lang="en">

<head>

<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="description" content="Online Shopping Website Using Spring MVC and Hibernate">
<meta name="author" content="Khozema Nullwala">
<meta name="_csrf" content="${_csrf.token}">
<meta name="_csrf_header" content="${_csrf.headerName}">

<title>Online Shopping - ${title}</title>

<script>
    window.menu = '${title}';

    window.contextRoot = '${contextRoot}'

</script>

<!-- Bootstrap core CSS -->
<link href="${css}/bootstrap.min.css" rel="stylesheet">

<%-- <!-- Bootstrap cyborg theme -->
 <link href="${css}/bootstrap-flatly-theme.css" rel="stylesheet">
 --%>

<link rel="stylesheet"
    href="https://use.fontawesome.com/releases/v5.4.1/css/all.css"
    integrity="sha384-5sAR7xN1Nv6T6+dT2mhtzEpVJvfS3NScPQTrOxhwjIuvcA67KV2R5Jz6kr4abQsz"
    crossorigin="anonymous">

<link href="https://fonts.googleapis.com/css?family=Tajawal:300&amp;subset=arabic" rel="stylesheet">

<!-- Bootstrap dataTables -->
<link href="${css}/dataTables.bootstrap4.css" rel="stylesheet">

<!-- Custom styles for this template -->
<link href="${css}/myapp.css" rel="stylesheet">
<link href="${css}/myapp2.css" rel="stylesheet">

<!-- HTML5 Shim and Respond.js IE8 support of HTML5 elements and media queries -->
<!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
<!--[if lt IE 9]>
        <script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
        <script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
    <![endif]-->

</head>

<body>

    <div class="se-pre-con"></div>
    <div class="wrapper" style="background-color: #e8eaed">

        <!-- Navigation -->
        <%@include file="./shared/navbar.jsp"%>

        <!-- Page Content -->

        <div class="content">

            <!-- Loading the home content -->
            <c:if test="${userClickHome == true }">
                <%@include file="home.jsp"%>
            </c:if>

            <!-- Load only when user clicks about -->
            <c:if test="${userClickAbout == true }">
                <%@include file="about.jsp"%>
            </c:if>

            <!-- Load only when user clicks contact -->
            <c:if test="${userClickContact == true }">
                <%@include file="contact.jsp"%>
            </c:if>

            <!-- Load only when user clicks contact -->
            <c:if test="${userClickAllProducts == true or userClickCategoryProducts == true }">
                <%@include file="listProducts.jsp"%>
            </c:if> 


            <!-- Load only when user clicks show product -->
            <c:if test="${userClickShowProduct == true}">
                <%@include file="singleProduct.jsp"%>
            </c:if>                             

            <!-- Load only when user clicks manage product -->
            <c:if test="${userClickManageProduct == true}">
                <%@include file="manageProduct.jsp"%>
            </c:if> 

            <!-- Load only when user clicks manage product -->
            <c:if test="${userClickShowCart == true}">
                <%@include file="cart.jsp"%>
            </c:if> 

            <!-- Load only when user clicks manage product -->
            <c:if test="${userClickViewProducts == true}">
                <%@include file="viewProducts.jsp"%>
            </c:if>

            <!-- Load only when user clicks manage product -->
            <c:if test="${userClickSearch == true}">
                <%@include file="search.jsp"%>
            </c:if> 
        </div>


        <!-- Footer comes here -->
        <%@include file="./shared/footer.jsp"%>

        <!-- jQuery -->
        <script src="${js}/jquery.js"></script>

        <script src="${js}/jquery.validate.js"></script>

        <!-- Bootstrap Core JavaScript -->
        <script src="${js}/bootstrap.min.js"></script>

        <!-- DataTable Plugin -->
        <script src="${js}/jquery.dataTables.js"></script>

        <!-- DataTable Bootstrap Script -->
        <script src="${js}/dataTables.bootstrap4.js"></script>

        <!-- DataTable Bootstrap Script -->
        <script src="${js}/bootbox.min.js"></script>

        <!-- Self coded javascript -->
        <script src="${js}/myapp.js"></script>
        <script src="${js}/myapp2.js"></script>

    </div>

</body>

</html>

application.properties

 server.port=8081
 logging.path=/home/vidyesh/Downloads
 server.servlet.context-path=/onlineshopping

WebAppInitializer.java

    package net.kzn.onlineshopping.config;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

public class WebAppInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext container) throws ServletException {
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        context.register(AppConfig.class);
        context.setServletContext(container);

        ServletRegistration.Dynamic servlet = container.addServlet("dispatcher", new DispatcherServlet(context));
        servlet.setLoadOnStartup(1);
        servlet.addMapping("/");
    }
}

file structure

please tell me what am i doing wrong here.

Answer 1

Well, First of all, maybe you use some dependencies for some personal raisons, but i tried to format your code as much as i can. PS: i did not try this code but you can do it and tell us if it's ok or not :

Pom

Can you set

<?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>net.kzn</groupId>
    <artifactId>onlineshopping</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>onlineshopping</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.6.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>net.kzn</groupId>
            <artifactId>shoppingbackend</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

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

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>

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

        <!-- This is a web application -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
        <!-- Tomcat embedded container-->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-tomcat</artifactId>
                <scope>provided</scope>
            </dependency>

        <!-- JSTL for JSP -->
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>jstl</artifactId>
            </dependency>

        <!-- Need this to compile JSP -->
            <dependency>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-jasper</artifactId>
                <scope>provided</scope>
            </dependency>

        <!-- Need this to compile JSP, tomcat-embed-jasper version is not working, no idea why -->
            <dependency>
                <groupId>org.eclipse.jdt.core.compiler</groupId>
                <artifactId>ecj</artifactId>
                <version>4.6.1</version>
                <scope>provided</scope>
            </dependency>

        <!-- Optional, test for static content, bootstrap CSS-->
            <dependency>
                <groupId>org.webjars</groupId>
                <artifactId>bootstrap</artifactId>
                <version>3.3.7</version>
            </dependency>
    </dependencies>

    <build>
            <plugins>
                <!-- Package as an executable jar/war -->
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
    </build>
</project>

Main class :

@SpringBootApplication
@EnableWebSecurity
@ImportResource({"classpath:/**/spring-security.xml"})
@ComponentScan(basePackages = {"net.kzn.onlineshopping.*","net.kzn.shoppingbackend.*"})
public class OnlineshoppingApplication  extends SpringBootServletInitializer{

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(OnlineshoppingApplication.class);
    }

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

In your page.jsp

<head> 
    ....
    <c:url value="/css/example.css" var="exampleCsss" />
    <link href="${exampleCss}" rel="stylesheet" />
</head>

In your aplication.properties, you add :

spring.mvc.view.prefix: /WEB-INF/jsp/
spring.mvc.view.suffix: .jsp

And your js files, try to put them just before closing your body tag.

Try also to have a structure like this if you can :)