Spring 弹簧靴&x2B；百里香叶=”；白标错误页“；尝试呈现index.html时

我正在尝试做简单的Spring MVC库你知道我为什么在视图方面有问题吗，当我在控制器中使用homepage方法时，它应该显示index.html，但我一直只能看到白标错误页面，我不知道为什么：/

我的结构： [

我的控制器：

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");
    }





}

---

您的演示项目有一些问题

1.包装结构不正确 您将您的

Runner

类放入默认包。这不是一个好主意，因为在这种情况下，Spring Boot无法为组件扫描设置默认包。当您运行应用程序时，您应该看到如下内容：

** WARNING ** : Your ApplicationContext is unlikely to start due to a @ComponentScan of the default package.

解决方案：将所有类移动到通用包

2.

spring boot starter thymeleaf

缺失 在您的

pom.xml

文件中，添加以下依赖项以使Thymeleaf模板工作：

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

3.

spring.thymeleaf.mode=LEGACYHTML5

需要额外的依赖关系 运行应用程序并打开时，您将看到以下异常：

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]

这是因为您已指定：

spring.thymeleaf.mode=LEGACYHTML5

您还没有将

nekoHTML

库添加到类路径中

解决方案：将以下依赖项添加到您的

pom.xml

：

    <!-- https://mvnrepository.com/artifact/org.thymeleaf/thymeleaf -->
    <dependency>
        <groupId>org.thymeleaf</groupId>
        <artifactId>thymeleaf</artifactId>
        <version>3.0.9.RELEASE</version>
    </dependency>

<dependency>
    <groupId>net.sourceforge.nekohtml</groupId>
    <artifactId>nekohtml</artifactId>
    <version>1.9.22</version>
</dependency>

net.sourceforge.nekohtml
内科特米尔
1.9.22

应用所有这些步骤后，您将在应用程序的主页上看到“Hello”。希望对您有所帮助

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]

spring.thymeleaf.mode=LEGACYHTML5

<dependency>
    <groupId>net.sourceforge.nekohtml</groupId>
    <artifactId>nekohtml</artifactId>
    <version>1.9.22</version>
</dependency>