Spring boot Resource Not Found 404错误html

Question

我构建了一个名为 Employer 的 crud 应用程序。操作工作正常，但是在 html 控制台中显示它们时显示错误 Not Found

: Resource not found
2019-07-29 05:04:25.834 DEBUG 18656 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed 404 NOT_FOUND
2019-07-29 05:04:25.834 DEBUG 18656 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : "ERROR" dispatch for GET "/error", parameters={}
2019-07-29 05:04:25.834 DEBUG 18656 --- [nio-8080-exec-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2019-07-29 05:04:25.834 DEBUG 18656 --- [nio-8080-exec-1] o.s.w.s.m.m.a.HttpEntityMethodProcessor  : Using 'application/json', given [*/*] and supported [application/json, application/*+json, application/json, application/*+json]
2019-07-29 05:04:25.834 DEBUG 18656 --- [nio-8080-exec-1] o.s.w.s.m.m.a.HttpEntityMethodProcessor  : Writing [{timestamp=Mon Jul 29 05:04:25 PDT 2019, status=404, error=Not Found, message=No message available,  (truncated)...]
2019-07-29 05:04:25.835 DEBUG 18656 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Exiting from "ERROR" dispatch, status 404
2019-07-29 05:04:37.741 DEBUG 18656 --- [nio-8080-exec-3] o.s.web.servlet.DispatcherServlet        : GET "/favicon.ico", parameters={}
2019-07-29 05:04:37.742 DEBUG 18656 --- [nio-8080-exec-3] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to ResourceHttpRequestHandler [class path resource [META-INF/resources/], class path resource [resources/], class path resource [static/], class path resource [public/], ServletContext resource [/], class path resource []]
2019-07-29 05:04:37.754 DEBUG 18656 --- [nio-8080-exec-3] o.s.web.servlet.DispatcherServlet        : Completed 200 OK

我尝试重新启动应用程序并更改实体的名称，但它没有用。以下是我尝试过的

雇主 Controller .java

package io.javabrains;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.hibernate.mapping.Index;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import io.javabrains.Entity.Employer;

@Controller
public class EmployerController {


    @Autowired
    private EmployerService service;




    @RequestMapping("/")
    public String newForm() {
        return "form1";
    }






     public List<Employer>getAllEmployers()
     {


        return  service.getAllEmployers();



     }

        @RequestMapping(value="/tables",method=RequestMethod.GET)

    public String getAllEmployers(Model model)
    {
         List<Employer>employers = service.getAllEmployers(); 
        model.addAttribute("Employer",employers);
        return "tables";
    }





      @RequestMapping("/employer/{id}") 
      public Employer getEmployer(@PathVariable Integer id) { 
          return service.getEmployers(id);
      }



    @RequestMapping(method=RequestMethod.POST,value="/employer")
    public void addEmployer(@RequestBody Employer employer) {
        service.addEmployer(employer);

    }


    @RequestMapping(method=RequestMethod.PUT,value="/employer/{id}")
    public void updateEmployer(@RequestBody Employer employer,@PathVariable int id) {
        service.updateEmployer(id,employer);
    }




      @RequestMapping(method=RequestMethod.DELETE,value="/create/{id}") 
     public void deleteEmployer(@PathVariable int id)
     {
          service.deleteEmployer(id);
     }




}

雇主服务.java

package io.javabrains;

import java.util.ArrayList;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import io.javabrains.Entity.Employer;

@Service
public class EmployerService {
    @Autowired
    private Repository repository;

    public List<Employer>getAllEmployers(){
        List<Employer>employers = new ArrayList<>();
        repository.findAll()
        .forEach(employers::add);
        return employers;

    }

    public void addEmployer(Employer employer) {
        repository.save(employer);
    }


    public void updateEmployer(int id, Employer employer) {
        repository.save(employer);
    }


    public void deleteEmployer(int id) {
        repository.deleteById(id);
        ;
    }



      public Employer getEmployers(int id) 
      { 
          return repository.getOne(id);

      }





}

雇主.Java

package io.javabrains;

import java.util.ArrayList;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import io.javabrains.Entity.Employer;

@Service
public class EmployerService {
    @Autowired
    private Repository repository;

    public List<Employer>getAllEmployers(){
        List<Employer>employers = new ArrayList<>();
        repository.findAll()
        .forEach(employers::add);
        return employers;

    }

    public void addEmployer(Employer employer) {
        repository.save(employer);
    }


    public void updateEmployer(int id, Employer employer) {
        repository.save(employer);
    }


    public void deleteEmployer(int id) {
        repository.deleteById(id);
        ;
    }



      public Employer getEmployers(int id) 
      { 
          return repository.getOne(id);

      }





}

表格.html

 <tbody>
                    <tr th:each="$(employers)">
                      <td th:text="${employers.name}"></td>
                      <td th:text="${employer.position}"></td>
                      <td th:text="${employer.office}"></td>
                      <td th:text="${employer.age}"></td>
                     <td th:text="${employer.salary}"></td>
                    </tr>

....

Answer 1

如果您在 Controller 类中使用@Controller (org.springframework.stereotype.Controller)，您还必须添加@ResponseBody每个 @RequestMapping 或在类级别。

或者，Spring 引入了 @RestController (org.springframework.stereotype.Controller.RestController)，其中包括 @Controller 和 @ResponseBody。

此外，您可以在 API 中尝试以下操作，我现在已经测试过并且有效。

@RequestMapping(path="/template")
public ModelAndView getHelloTemplate(){
    ModelAndView model = new ModelAndView();
    model.setViewName("hello");
    model.addObject("message", "Hello World");
    return model;
}

我使用了 spring-boot-starter-freemarker 模板引擎，html 文件位于 `src/main/resources/templates/hello.ftl' 下。

现在，我已经用 Thymeleaf 测试了相同的代码并且它有效。

pom.xml:

<!--<dependency>-->
<!--<groupId>org.springframework.boot</groupId>-->
<!--<artifactId>spring-boot-starter-freemarker</artifactId>-->
<!--<version>2.1.2.RELEASE</version>-->
<!--</dependency>-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
    <version>2.1.2.RELEASE</version>
</dependency>

Controller :

@Controller(value = "tvGuideController")
public class TvGuideController {
    @RequestMapping(path="/template")
    public ModelAndView getHelloTemplate(){
        ModelAndView model = new ModelAndView();
        model.setViewName("hello");
        model.addObject("message", "Hello World");
        return model;
    }

    @RequestMapping(path="/template1")
    public String getHelloTemplate(Model model){
        model.addAttribute("message", "Hello World 1");
        return "hello";
    }

    @RequestMapping(path="/template2")
    public String getHelloTemplate(ModelMap model){
        model.addAttribute("message", "Hello World 2");
        return "hello2";
    }
}

同时具有 Thymeleaf 和 Freemarker 模板引擎的运行应用程序可用 at github克隆存储库并运行应用程序:

git clone https://github.com/fiveobjects/reference.git
cd java/springboot
mvn spring-boot:run

URL(端口可能因您而异):

http://localhost:8080/template
http://localhost:8080/template1
http://localhost:8080/template2

如果您想在 pom.xml 中运行 freemarker 而不是 thymeleaf，请注释掉 thymeleaf 依赖项并取消注释 freemarker 依赖项。

如果这对你有用，那么你的 pom.xml 依赖项、application.properties、主应用程序类和 Controller 肯定需要检查。