How can I cope with a circular view path error?
package com.example.PrinterManager;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
#Controller
public class ControllerPrinter {
#GetMapping("/home")
public String getHomePage() {
return "home"; // Breakpoint.
}
}
The interpreter stops at the breakpoint. But then the error occurs.
As for the template, it is here (visible in the picture)
PrinterManager\src\main\resources\templates\home.html
Simply change #Controller → #RestController,
For more details look at that
There are two possible ways to solve this problem:
1: add a thymeleaf to your dependencies:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
if no luck, try next one:
2: change your home.html to another name, for example, index.html, then change your controller to:
#Controller
public class ControllerPrinter {
#GetMapping("/home")
public String getHomePage() {
return "index"; // Breakpoint.
}
}
I used maven to do the tutorial https://spring.io/guides/gs/uploading-files/
All the codes I used was copied.
The Application can run, but I get the error:
Whitelabel Error Page This application has no explicit mapping for /error, so you are seeing this as a fallback.
Tue Jun 30 17:24:02 CST 2015 There was an unexpected error (type=Not Found, status=404).
No message available
How can I fix it?
Make sure that your main class is in a root package above other classes.
When you run a Spring Boot Application, (i.e. a class annotated with #SpringBootApplication), Spring will only scan the classes below your main class package.
com
+- APP
+- Application.java <--- your main class should be here, above your controller classes
|
+- model
| +- user.java
+- controller
+- UserController.java
When we create a Spring boot application we annotate it with #SpringBootApplication annotation. This annotation 'wraps up' many other necessary annotations for the application to work. One such annotation is #ComponentScan annotation. This annotation tells Spring to look for Spring components and configure the application to run.
Your application class needs to be top of your package hierarchy, so that Spring can scan sub-packages and find out the other required components.
package com.test.spring.boot;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class App {
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
}
Below code snippet works as the controller package is under com.test.spring.boot package
package com.test.spring.boot.controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
#RestController
public class HomeController {
#RequestMapping("/")
public String home(){
return "Hello World!";
}
}
Below code snippet does NOT Work as the controller package is NOT under com.test.spring.boot package
package com.test.controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
#RestController
public class HomeController {
#RequestMapping("/")
public String home(){
return "Hello World!";
}
}
From Spring Boot documentation:
Many Spring Boot developers always have their main class annotated
with #Configuration, #EnableAutoConfiguration and #ComponentScan.
Since these annotations are so frequently used together (especially if
you follow the best practices above), Spring Boot provides a
convenient #SpringBootApplication alternative.
The #SpringBootApplication annotation is equivalent to using
#Configuration, #EnableAutoConfiguration and #ComponentScan with their
default attributes
You can solve this by adding an ErrorController in your application. You can have the error controller return a view that you need.
Error Controller in my application looks like below:
import org.springframework.boot.autoconfigure.web.ErrorAttributes;
import org.springframework.boot.autoconfigure.web.ErrorController;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import java.util.Map;
/**
* Basic Controller which is called for unhandled errors
*/
#Controller
public class AppErrorController implements ErrorController{
/**
* Error Attributes in the Application
*/
private ErrorAttributes errorAttributes;
private final static String ERROR_PATH = "/error";
/**
* Controller for the Error Controller
* #param errorAttributes
*/
public AppErrorController(ErrorAttributes errorAttributes) {
this.errorAttributes = errorAttributes;
}
/**
* Supports the HTML Error View
* #param request
* #return
*/
#RequestMapping(value = ERROR_PATH, produces = "text/html")
public ModelAndView errorHtml(HttpServletRequest request) {
return new ModelAndView("/errors/error", getErrorAttributes(request, false));
}
/**
* Supports other formats like JSON, XML
* #param request
* #return
*/
#RequestMapping(value = ERROR_PATH)
#ResponseBody
public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
Map<String, Object> body = getErrorAttributes(request, getTraceParameter(request));
HttpStatus status = getStatus(request);
return new ResponseEntity<Map<String, Object>>(body, status);
}
/**
* Returns the path of the error page.
*
* #return the error path
*/
#Override
public String getErrorPath() {
return ERROR_PATH;
}
private boolean getTraceParameter(HttpServletRequest request) {
String parameter = request.getParameter("trace");
if (parameter == null) {
return false;
}
return !"false".equals(parameter.toLowerCase());
}
private Map<String, Object> getErrorAttributes(HttpServletRequest request,
boolean includeStackTrace) {
RequestAttributes requestAttributes = new ServletRequestAttributes(request);
return this.errorAttributes.getErrorAttributes(requestAttributes,
includeStackTrace);
}
private HttpStatus getStatus(HttpServletRequest request) {
Integer statusCode = (Integer) request
.getAttribute("javax.servlet.error.status_code");
if (statusCode != null) {
try {
return HttpStatus.valueOf(statusCode);
}
catch (Exception ex) {
}
}
return HttpStatus.INTERNAL_SERVER_ERROR;
}
}
The above class is based on Springs BasicErrorController class.
You can instantiate the above ErrorController like this in a #Configuration file:
#Autowired
private ErrorAttributes errorAttributes;
#Bean
public AppErrorController appErrorController(){return new AppErrorController(errorAttributes);}
You can choose override the default ErrorAttributes by implementing ErrorAttributes. But in most cases the DefaultErrorAttributes should suffice.
In my case the controller class was annotated with #Controller. Changing that to #RestController resolved the problem.
Basically #RestController is #Controller + #ResponseBody
So either use #RestController , or #Controller with #ResponseBody annotation with each method.
Some useful notes here : https://www.genuitec.com/spring-frameworkrestcontroller-vs-controller/
in my case it because of package position , meaning package of controller must be above main class package
if my main class package is package co.companyname.spring.tutorial; any controller package should package co.companyname.spring.tutorial.WHAT_EVER_HERE;
package co.companyname.spring.tutorial; // package for main class
#SpringBootApplication
public class FirstProjectApplication {
public static void main(String[] args) {
SpringApplication.run(FirstProjectApplication.class, args);
}
}
package co.companyname.spring.tutorial.controllers; // package for controllers
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
#RestController
public class HelloController {
#RequestMapping("/hello")
public String hello() {
return "Hello, world";
}}
after finish coding press boot dashboard
one last thing to make sure your controller is mapping or not just console you should see somehting smilliar
Mapped "{[/hello]}" onto public java.lang.String co.companyname.spring.tutorial.controllers.HelloController.hello()
happy coding
Try adding the dependency.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
This happens when an explicit error page is not defined. To define an error page, create a mapping of /error with a view.
e.g. the below code maps to a string value being returned in case of an error.
package com.rumango.controller;
import org.springframework.boot.web.servlet.error.ErrorController;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
#Controller
public class IndexController implements ErrorController{
private final static String PATH = "/error";
#Override
#RequestMapping(PATH)
#ResponseBody
public String getErrorPath() {
// TODO Auto-generated method stub
return "No Mapping Found";
}
}
By default spring boot will scan current package for bean definition. So if your current package where main class is defined and controller package is not same or controller package is not child package of your main app package it will not scan the controller. To solve this issue one can include list of packages for bean definition in main package
#SpringBootApplication(scanBasePackages = {"com.module.restapi1.controller"})
or create a hierarchy of package where child package is derived from main package
package com.module.restapi;
package com.module.restapi.controller
In the main class, after the configuration "#SpringBootApplication", adding "#ComponentScan" without having any arguments, worked for me !!!
Main Class :
#SpringBootApplication
#ComponentScan
public class CommentStoreApplication {
public static void main(String[] args) {
SpringApplication.run(CommentStoreApplication.class, args);
}
}
RestController Class :
#RestController
public class CommentStoreApp {
#RequestMapping("/")
public String hello() {
return "Hello World!";
}
}
P.S: Don't miss to run mvn clean and mvn install commands, before launching the application
I am developing Spring Boot application for a few weeks.. And I was gettig same error like below;
Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.
Thu Jan 18 14:12:11 AST 2018
There was an unexpected error (type=Not Found, status=404).
No message available
When I get this error massage I realized my controller or rest controller class is not defined in my project. I mean our all controller packages aren't same package with main class which include #SpringBootApplication annotation.. I mean you need to add you controller package's name to #ComponentScan annotation to your main class which is includes #SpringBootApplication annotation. If you write codes of below your problem will be solving... Most important thing is you have to add your all controller's package to #ComponentScan annotation like I did in the below
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
#SpringBootApplication
#ComponentScan({ "com.controller.package1, com.controller.package2, com.controller.package3, com.controller.packageN", "controller", "service" } // If our Controller class or Service class is not in the same packages we have //to add packages's name like this...directory(package) with main class
public class MainApp {
public static void main(String[] args) {
SpringApplication.run(MainApp.class, args);
}
}
I hope this codes are going to help someone...
If you find another way to solve this error or you have some suggestions for me,
please write to comments... thanks...
I added this dependency and it solved my problem.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
You might be getting the error i.e.
"This application has no explicit mapping for /error, so you are seeing this as a fallback."
This is because it is not scanning your Controller & Service classes which you have to specify in your main() class like this,
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
#Configuration
#EnableAutoConfiguration
**#ComponentScan({"com.example.demo", "controller", "service"})**
public class SpringBootMvcExample1Application {
public static void main(String[] args) {
SpringApplication.run(SpringBootMvcExample1Application.class, args);
}
}
Note: Here, I have specified various classes like demo, controller and service to be scanned then only it will work properly.
Quite late to the party. As per spring official documentation "Spring Boot installs a whitelabel error page that you see in a browser client if you encounter a server error."
https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#howto-customize-the-whitelabel-error-page
You can disable the feature by setting server.error.whitelabel.enabled=false in application.yml or application.properties file.
2.Recommended way is set your error page so that end user can understand. Under resources/templates folder create a error.html file and add dependency in pom.xml file
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
Spring will automatically choose the error.html page as the default error template.
Note:- Don't forget to update maven project after adding dependency.
You have to organize the packages so that the package containing public static main(or where you wrote #SpringBootApplication), the father of all your other packages.
The problem is that you are navigating to localhost:8080/ instead of localhost:8080/upload as prescribed in the guide. Spring Boot has a default error page used when you navigate to an undefined route to avoid giving away server specific details (which can be viewed as a security risk).
You're options are to either: visit the right page, add your own landing page, or override the white error page.
To simplify this particular situation, I updated the guide so that it uses / instead of /upload.
I too got the same error and was able to resolve the error by adding the below dependency to my pom.xml.
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>
Reason is we are using JSP as the view. Default embedded servlet container for Spring Boot Starter Web is tomcat.
To enable support for JSP’s, we would need to add a dependency on tomcat-embed-jasper.
In my case I was returning a JSP as view from controller.
Hope this answer helps someone who are struggling with same issue.
I know it's not exactly answer to question, but this question is first which appears on Google :)
Problem ("This application has no explicit mapping for /error") appears when trying to access Swagger UI.
In my case problems were caused by #RestController("/endpoint"), which isn't handled properly by swagger.
So, this resulted in errors:
#RestController("/endpoint")
public class EndpointController {
And this was fine
#RestController
#RequestMapping("/endpoint")
public class EndpointController {
this can happen if you forget the #RestController annotation on top of your controller class
import import org.springframework.web.bind.annotation.RestController;
and add the annotation as below
refer the simple example below
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.RequestMapping;
#RestController
public class HelloController {
#RequestMapping("/")
public String index() {
return "Greetings from Spring Boot!";
}
}
Ensure that you have jasper and jstl in the list of dependencies:
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
</dependency>
Here is a working starter project - https://github.com/spring-projects/spring-boot/tree/master/spring-boot-samples/spring-boot-sample-web-jsp
Author: Biju Kunjummen
I need to mention this way and give the reference to packages and it worked out. You may exclude #EnableAutoConfiguration this annotation but required for me to bypass any DB related depenencies.
#SpringBootApplication
#EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
#ComponentScan(basePackages = {"your package 1", "your package2"})
public class CommentStoreApplication {
public static void main(String[] args) {
SpringApplication.run(CommentStoreApplication.class, args);
}
}
Same problem I have faced recently. I have solved it by just getter and setter method spelling correction!
The tutorial expects you to have the Thymeleaf template engine in classpath. I ran into the same problem and finally figured this out. I'll reach out to the tutorial author to include that info.
The easiest way if you've followed the tutorial is to add the dependency to your pom.xml in the project root folder. Next time you run your app Spring will detect Thymeleaf and use the uploadform template
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
For the full example see their Github repository.
Change #Controller to #RestController in your controller class and everything should go smoothly.
I was facing the same problem, using gradle and it got solved on adding following dependencies-
compile('org.springframework.boot:spring-boot-starter-data-jpa')
compile('org.springframework.boot:spring-boot-starter-web')
testCompile('org.springframework.boot:spring-boot-starter-test')
compile('org.apache.tomcat.embed:tomcat-embed-jasper')
earlier I was missing the last one causing the same error.
I was facing this issue and then later realized that I was missing the #Configuration annotation in the MvcConfig class which basically does the mapping for ViewControllers and setViewNames.
Here is the content of the file :
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
**#Configuration**
public class MvcConfig implements WebMvcConfigurer{
public void addViewControllers(ViewControllerRegistry registry)
{
registry.addViewController("/").setViewName("login");
registry.addViewController("/login").setViewName("login");
registry.addViewController("/dashboard").setViewName("dashboard");
}
}
Hope this helps somebody!!
Make sure #RestController annotation is added right after the #SpringBootApplication.
RestController annotation tells Spring that this code describes an endpoint that should be made available over the web.
You may have not included thymleaf in your pom.xml file.
I had a similar problem. And I had Main.class on the top of all the controllers, yet I was facing this issue. All I needed to do is to create a separate swagger configuration file and initialize docket bean in it.
note: location of this file should be either in the same package of the Main.class file or in a package inside that main package.
SwaggerCongiguration.java file
package com.example.springDataJPAUsingGradle;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;
#Configuration
#EnableSwagger2
public class SwaggerConfig {
#Bean
public Docket docket() {
return new Docket(DocumentationType.SWAGGER_2).select().build();
}
}
I also had to add #RequestMapping("/api") in my controller.java.
Here's how:
package com.example.springDataJPAUsingGradle.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.example.springDataJPAUsingGradle.service.StudentService;
#RestController
#RequestMapping("/api")
public class StudentController {
#Autowired(required = true)
#GetMapping("/home")
public String home() {
return "Welcome to home page";
}
}
Then after hitting the url: http://localhost:9090/your-app-root/swagger-ui/ swagger UI will be visible.
For eg, in my case the url is: http://localhost:9090/students/swagger-ui/
All I have done to solve this kind of problem is to mention anotation #Configuration in MVCConfig Class.
Like this one :
package com.example;
/**
* Created by sartika.s.hasibuan on 1/10/2017.
*/
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
#EnableAutoConfiguration
#Configuration
#ComponentScan
public class MvcConfig extends WebMvcConfigurerAdapter {
#Override
public void addViewControllers(ViewControllerRegistry registry) {
registry.addViewController("/home").setViewName("home");
registry.addViewController("/").setViewName("home");
registry.addViewController("/hello").setViewName("hello");
registry.addViewController("/login").setViewName("login");
}
}
I had a similar mistake, I use the spring boot and velocity, my solution is to check the file application.properties, spring.velocity.toolbox-config-location found that this property is wrong