Question

我是Spring Boot开发的新手，请帮我解决以下错误

目录结构（仅包括重要文件的结构）

src
   -main
       -java
           -com.example.handlingformsubmission
               -Greeting.java
               -GreetingController.java
               -HandlingFormSubmissionApplication.java
       -resources
           -templates
               -greeting.html
               -result.html
           -application.properties
   -test
       -java
           -com.example.handlingformsubmission
               -HandlingFormSubmissionApplicationTest.java
   -build.gradle

在执行过程中，当我在浏览器上运行该错误时

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Wed Mar 11 19:08:44 IST 2020
There was an unexpected error (type=Not Found, status=404).
No message available

以及当我终止或停止应用程序时

Execution failed for task ':HandlingFormSubmissionApplication.main()'.
> Process 'command '/usr/lib/jvm/java-11-amazon-corretto/bin/java'' finished with non-zero exit value 143

当前我正在使用springboot版本2.2.2

这是我的代码

build.gradle

plugins {
    id 'org.springframework.boot' version '2.2.2.RELEASE'
    id 'io.spring.dependency-management' version '1.0.8.RELEASE'
    id 'java'
    id 'war'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    testImplementation('org.springframework.boot:spring-boot-starter-test') {
        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
    }
}

test {
    useJUnitPlatform()
}

HandlingFormSubmissionApplication.java

package com.example.handlingformsubmission;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

@ComponentScan(basePackages = {"com.example.handlingformsubmission.greeting"})
@SpringBootApplication
public class HandlingFormSubmissionApplication {

    public static void main(String[] args) {
        SpringApplication.run(HandlingFormSubmissionApplication.class, args);
    }

}

GreetingController.java


package com.example.handlingformsubmission.greeting;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PostMapping;

@Controller
public class GreetingController {

    @GetMapping("/greeting")
    public String greetingForm(Model model) {
        model.addAttribute("greeting", new Greeting());
        return "greeting";
    }

    @PostMapping("/greeting")
    public String greetingSubmit(@ModelAttribute Greeting greeting, Model model) {
        model.addAttribute("greeting", greeting);
        return "result";
    }

}

application.properties

server.port=8000

greeting.html

<!DOCTYPE HTML>
<html xmlns:th="https://www.thymeleaf.org">
<head> 
    <title>Getting Started: Handling Form Submission</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
    <h1>Form</h1>
    <form action="#" th:action="@{/greeting}" th:object="${greeting}" method="post">
        <p>Id: <input type="text" th:field="*{id}" /></p>
        <p>Message: <input type="text" th:field="*{content}" /></p>
        <p><input type="submit" value="Submit" /> <input type="reset" value="Reset" /></p>
    </form>
</body>
</html>

result.html

<!DOCTYPE HTML>
<html xmlns:th="https://www.thymeleaf.org">
<head> 
    <title>Getting Started: Handling Form Submission</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
    <h1>Result</h1>
    <p th:text="'id: ' + ${greeting.id}" />
    <p th:text="'content: ' + ${greeting.content}" />
    <a href="/greeting">Submit another message</a>
</body>
</html>

Answer 1

问题中未指定，但是我想您要执行GET http://localhost:8000/greeting

我不会修复您的表单，但是 404 可以通过修复您的@ComponentScan来解决，例如...

// wrong: '.greeting' excludes the 'GreetingController'
@ComponentScan(basePackages = {"com.example.handlingformsubmission.greeting"})

// fixed: specifies a valid path that includes the controller
@ComponentScan(basePackages = {"com.example.handlingformsubmission"})

解决此问题后，您将可以继续解决下一个问题：

发生意外错误（类型=内部服务器错误，状态= 500）。模板解析期间发生错误（模板： “类路径资源[templates / greeting.html]”）

您还可以通过完全删除@ComponentScan来解决此问题-在此初始方案中不需要。

为Spring-boot应用程序获取whitelabel错误

1 个答案: