2020年9月9日 22:28:49go评论91阅读模式

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/.

  .   ____          _            __ _ _
 /\\ / ___&#39;_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | &#39;_ | &#39;_| | &#39;_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  &#39;  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: 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 &#39;resourceHandlerMapping&#39;
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=&#39;false&#39;: 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 &quot;/hello&quot;
2020-09-09 16:12:07.998 DEBUG 19440 --- [ctor-http-nio-2] o.s.w.r.handler.SimpleUrlHandlerMapping  : [22183960-1] Mapped to ResourceWebHandler [&quot;classpath:/META-INF/resources/&quot;, &quot;classpath:/resources/&quot;, &quot;classpath:/static/&quot;, &quot;classpath:/public/&quot;]
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 &quot;&lt;html&gt;&lt;body&gt;&lt;h1&gt;Whitelabel Error Page&lt;/h1&gt;&lt;p&gt;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(&quot;/hello&quot;)
	public String hello(@RequestParam(value = &quot;name&quot;, defaultValue = &quot;World&quot;) String name) {
		return String.format(&quot;Hello %s!&quot;, name);
	}
}

pom.xml

&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
&lt;project xmlns=&quot;http://maven.apache.org/POM/4.0.0&quot; xmlns:xsi=&quot;http://www.w3.org/2001/XMLSchema-instance&quot;
	xsi:schemaLocation=&quot;http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd&quot;&gt;
	&lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
	&lt;parent&gt;
		&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
		&lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
		&lt;version&gt;2.3.3.RELEASE&lt;/version&gt;
		&lt;relativePath/&gt; &lt;!-- lookup parent from repository --&gt;
	&lt;/parent&gt;
	&lt;groupId&gt;com.example.demo&lt;/groupId&gt;
	&lt;artifactId&gt;demo&lt;/artifactId&gt;
	&lt;version&gt;0.0.1-SNAPSHOT&lt;/version&gt;
	&lt;name&gt;demo&lt;/name&gt;
	&lt;description&gt;Demo project for Spring Boot&lt;/description&gt;
	&lt;properties&gt;
		&lt;java.version&gt;1.8&lt;/java.version&gt;
	&lt;/properties&gt;
	&lt;dependencies&gt;
		&lt;dependency&gt;
			&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
			&lt;artifactId&gt;spring-boot-starter-webflux&lt;/artifactId&gt;
		&lt;/dependency&gt;
		&lt;dependency&gt;
			&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
			&lt;artifactId&gt;spring-boot-starter-test&lt;/artifactId&gt;
			&lt;scope&gt;test&lt;/scope&gt;
			&lt;exclusions&gt;
				&lt;exclusion&gt;
					&lt;groupId&gt;org.junit.vintage&lt;/groupId&gt;
					&lt;artifactId&gt;junit-vintage-engine&lt;/artifactId&gt;
				&lt;/exclusion&gt;
			&lt;/exclusions&gt;
		&lt;/dependency&gt;
		&lt;dependency&gt;
			&lt;groupId&gt;io.projectreactor&lt;/groupId&gt;
			&lt;artifactId&gt;reactor-test&lt;/artifactId&gt;
			&lt;scope&gt;test&lt;/scope&gt;
		&lt;/dependency&gt;
	&lt;/dependencies&gt;
	&lt;build&gt;
		&lt;plugins&gt;
			&lt;plugin&gt;
				&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
				&lt;artifactId&gt;spring-boot-maven-plugin&lt;/artifactId&gt;
			&lt;/plugin&gt;
		&lt;/plugins&gt;
	&lt;/build&gt;
&lt;/project&gt;

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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白标错误页面。此应用未配置错误视图，因此您正在看到此页面作为回退。

问题

答案1

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