英文:
Whitelabel Error Page This application has no configured error view, so you are seeing this as a fallback
问题
我开始构建一个Spring Boot应用程序，但是我遇到了这种错误：“白标错误页面 - 此应用程序没有配置错误视图，因此您正在看到此回退。”<br>
我是从https://start.spring.io/创建的项目。
DemoApplication.java
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
@GetMapping("/hello")
public String hello(@RequestParam(value = "name", defaultValue = "World") String name) {
return String.format("Hello %s!", name);
}
}
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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example.demo</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.projectreactor</groupId>
<artifactId>reactor-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
项目结构：
我不理解问题出在哪里。
英文:
I am started building a spring boot application but i am getting this type of error "Whitelabel Error Page - This application has no configured error view, so you are seeing this as a fallback." <br>
I created the project from https://start.spring.io/.
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.3.3.RELEASE)
2020-09-09 16:12:00.389 INFO 19440 --- [ main] com.example.demo.DemoApplication : Starting DemoApplication on ***** with PID 19440 (C:\Users\m.petraglia\Desktop\demo\target\classes started by m.petraglia in C:\Users\m.petraglia\Desktop\demo)
2020-09-09 16:12:00.391 INFO 19440 --- [ main] com.example.demo.DemoApplication : No active profile set, falling back to default profiles: default
2020-09-09 16:12:01.024 DEBUG 19440 --- [ main] o.s.w.r.handler.SimpleUrlHandlerMapping : Patterns [/webjars/**, /**] in 'resourceHandlerMapping'
2020-09-09 16:12:01.118 DEBUG 19440 --- [ main] o.s.w.r.r.m.a.ControllerMethodResolver : ControllerAdvice beans: none
2020-09-09 16:12:01.138 DEBUG 19440 --- [ main] o.s.w.s.adapter.HttpWebHandlerAdapter : enableLoggingRequestDetails='false': form data and headers will be masked to prevent unsafe logging of potentially sensitive data
2020-09-09 16:12:01.961 INFO 19440 --- [ main] o.s.b.web.embedded.netty.NettyWebServer : Netty started on port(s): 8080
2020-09-09 16:12:01.967 INFO 19440 --- [ main] com.example.demo.DemoApplication : Started DemoApplication in 1.837 seconds (JVM running for 2.132)
2020-09-09 16:12:07.977 DEBUG 19440 --- [ctor-http-nio-2] o.s.w.s.adapter.HttpWebHandlerAdapter : [22183960-1] HTTP GET "/hello"
2020-09-09 16:12:07.998 DEBUG 19440 --- [ctor-http-nio-2] o.s.w.r.handler.SimpleUrlHandlerMapping : [22183960-1] Mapped to ResourceWebHandler ["classpath:/META-INF/resources/", "classpath:/resources/", "classpath:/static/", "classpath:/public/"]
2020-09-09 16:12:08.000 DEBUG 19440 --- [ctor-http-nio-2] o.s.w.r.resource.ResourceWebHandler : [22183960-1] Resource not found
2020-09-09 16:12:08.025 DEBUG 19440 --- [ctor-http-nio-2] org.springframework.web.HttpLogging : [22183960-1] Resolved [ResponseStatusException: 404 NOT_FOUND] for HTTP GET /hello
2020-09-09 16:12:08.031 DEBUG 19440 --- [ctor-http-nio-2] org.springframework.web.HttpLogging : [22183960-1] Writing "<html><body><h1>Whitelabel Error Page</h1><p>This application has no configured error view, so you (truncated)...
2020-09-09 16:12:08.042 DEBUG 19440 --- [ctor-http-nio-2] o.s.w.s.adapter.HttpWebHandlerAdapter : [22183960-1] Completed 404 NOT_FOUND
DemoApplication.java
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
@GetMapping("/hello")
public String hello(@RequestParam(value = "name", defaultValue = "World") String name) {
return String.format("Hello %s!", name);
}
}
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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example.demo</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.projectreactor</groupId>
<artifactId>reactor-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Project structure:
I don't understand what is the problem.
答案1
得分: 2
尝试在类上添加 @RestController 注解
英文:
Try adding @RestController annotation to the class
答案2
得分: 0
或许你应该使用 HTML 文件在浏览器中运行它，这是我的意见。如果你使用 Thymeleaf，也要包含相关的依赖。
英文:
maybe you should use html file to run it in browser in my opinion,and also if you use thymeleaf include the dependencies as well
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