Spring Boot + Thymeleaf = "Whitelabel Error Page" when trying to render index.html - spring

Question

I am trying to do simple Spring MVC LibraryDo You have any idea why I have problem with View, when i use homepage method in my controller it should show me index.html but i only get Whitelabel Error Page all the time, and i dont know why:/
My structure:
[https://i.imgur.com/5TrGGrB.png]
My controller:
package controller;
import model.Book;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
import service.BookService;
import javax.servlet.http.HttpServletRequest;
import java.util.List;
#Controller
public class LiberianController{
#Autowired
private BookService bookService;
#RequestMapping(value = "/")
public String homepage() {
return "index";
}
#GetMapping(value = "/allBooks")
public ModelAndView allBooks(ModelAndView modelAndView) {
List<Book> books = bookService.getAllBooks();
modelAndView.addObject("listBooks", books);
modelAndView.setViewName("allBooks");
return modelAndView;
}
#GetMapping(value = "/addBook")
public ModelAndView newBook(ModelAndView modelAndView) {
Book book = new Book();
modelAndView.addObject("book", book);
modelAndView.setViewName("addBook");
return modelAndView;
}
#GetMapping(value = "updateBook")
public ModelAndView updateBook(HttpServletRequest httpServletRequest) {
long id = Long.parseLong(httpServletRequest.getParameter("id"));
Book book = bookService.getBook(id);
ModelAndView modelAndView = new ModelAndView("addBook");
modelAndView.addObject("book", book);
return modelAndView;
}
#RequestMapping(value = "/saveBook",method = RequestMethod.POST)
public ModelAndView saveBook(#ModelAttribute Book book) {
if (book.getId() == 0) {
bookService.addBook(book);
} else {
bookService.updateBook(book.getId(), book);
}
return new ModelAndView("redirect:/allBooks");
}
#GetMapping(value = "/deleteBook")
public ModelAndView deleteBook(HttpServletRequest httpServletRequest) {
long id = Long.parseLong(httpServletRequest.getParameter("id"));
bookService.deleteBook(id);
return new ModelAndView("redirect:/allBooks");
}
}
My POM:
<?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>MyLibrary</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.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-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.2.12.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
</dependency>
<!-- https://mvnrepository.com/artifact/org.thymeleaf/thymeleaf -->
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf</artifactId>
<version>3.0.9.RELEASE</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Something</title>
</head>
<body>
<h1>Hello</h1>
</body>
</html>
aplication.properties
spring.jpa.hibernate.ddl-auto=update
spring.datasource.url=jdbc:mysql://localhost:3306/book?useSSL=false
spring.datasource.username=root
spring.datasource.password=root
spring.mvc.view.prefix=/WEB-INF/
spring.mvc.view.suffix=.jsp
spring.thymeleaf.mode=LEGACYHTML5

Answer 1

There are a few things wrong with your demo project.
1. Incorrect package structure
You put your Runner class to a default package. It not a good idea, because in this case Spring Boot is not able to set a default package for component scanning. When you run your application you should see something like:
** WARNING ** : Your ApplicationContext is unlikely to start due to a #ComponentScan of the default package.
Solution: move all your classes to common package.
2. spring-boot-starter-thymeleaf is missing
In your pom.xml file add following dependency to make Thymeleaf templates working:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
Then remove following dependency that is present in your pom.xml:
<!-- https://mvnrepository.com/artifact/org.thymeleaf/thymeleaf -->
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf</artifactId>
<version>3.0.9.RELEASE</version>
</dependency>
3. spring.thymeleaf.mode=LEGACYHTML5 requires additional dependency
When you run your app and you open http://localhost:8080 you will see following exception:
org.thymeleaf.exceptions.ConfigurationException: Cannot perform conversion to XML from legacy HTML: The nekoHTML library is not in classpath. nekoHTML 1.9.15 or newer is required for processing templates in "LEGACYHTML5" mode [http://nekohtml.sourceforge.net]. Maven spec: "net.sourceforge.nekohtml::nekohtml::1.9.15". IMPORTANT: DO NOT use versions of nekoHTML older than 1.9.15.
at org.thymeleaf.templateparser.html.AbstractHtmlTemplateParser.parseTemplate(AbstractHtmlTemplateParser.java:90) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.thymeleaf.TemplateRepository.getTemplate(TemplateRepository.java:278) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1104) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1060) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1011) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
This is because you have specified:
spring.thymeleaf.mode=LEGACYHTML5
and you haven't add nekoHTML library to the classpath.
Solution: add following dependency to your pom.xml:
<dependency>
<groupId>net.sourceforge.nekohtml</groupId>
<artifactId>nekohtml</artifactId>
<version>1.9.22</version>
</dependency>
After applying all these steps you will see "Hello" on your app's home page. Hope it helps.