弹簧启动 MVC 模板未加载（404 未找到）

java spring spring-mvc spring-boot

2022-09-01 08:15:13

我在这里有一个非常简单的Spring-Boot MVC应用程序，它不起作用。一个控制器有一个页面未加载，但未找到404。

我在控制器方法中放置了一个System.out.println（“主页”）语句，并验证它是否已映射并正确触发，但模板未加载。

错误：

Whitelabel Error Page

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

Thu Nov 06 23:43:51 EST 2014
There was an unexpected error (type=Not Found, status=404).

文件夹结构：

src/main/java
 +-Application.java
 +-WebController.java

src/main/resources
 +-templates
   +-index.html

缩写的控制台输出：

Server initialized with port: 8080
Starting service Tomcat
Starting Servlet Engine: Apache Tomcat/7.0.55
Initializing Spring embedded WebApplicationContext
Root WebApplicationContext: initialization completed in 1947 ms
Mapping servlet: 'dispatcherServlet' to [/]
Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
Mapped "{[/],methods=[],params=[],headers=[],consumes=[],produces=[],custom=[]}" onto public java.lang.String app.WebController.index()
Tomcat started on port(s): 8080/http
Started Application in 5.552 seconds (JVM running for 6.366)
Home Page
Home Page
Home Page

配置：

@EnableAutoConfiguration
@Configuration
@ComponentScan
public class Application extends WebMvcConfigurerAdapter {
    public static void main(String[] args) {
         ConfigurableApplicationContext context = SpringApplication.run(Application.class);
    }
}

控制器：

@Controller
public class WebController {
    @RequestMapping(value="/")
    public String index(){
        System.out.println("Home Page");
        return "index";
    }
}

索引.html ：

<!DOCTYPE html>
<html lang="en">
<body>
 <h1>Hello</h1>    
</body>
</html>

我在这里有一个非常简单的Spring-Boot MVC应用程序，它不起作用。一个控制器有一个页面未加载，但未找到404。

我在控制器方法中放置了一个System.out.println（“主页”）语句，并验证它是否已映射并正确触发，但模板未加载。

错误：

Whitelabel Error Page

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

Thu Nov 06 23:43:51 EST 2014
There was an unexpected error (type=Not Found, status=404).

文件夹结构：

src/main/java
 +-Application.java
 +-WebController.java

src/main/resources
 +-templates
   +-index.html

缩写的控制台输出：

Server initialized with port: 8080
Starting service Tomcat
Starting Servlet Engine: Apache Tomcat/7.0.55
Initializing Spring embedded WebApplicationContext
Root WebApplicationContext: initialization completed in 1947 ms
Mapping servlet: 'dispatcherServlet' to [/]
Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
Mapped "{[/],methods=[],params=[],headers=[],consumes=[],produces=[],custom=[]}" onto public java.lang.String app.WebController.index()
Tomcat started on port(s): 8080/http
Started Application in 5.552 seconds (JVM running for 6.366)
Home Page
Home Page
Home Page

配置：

@EnableAutoConfiguration
@Configuration
@ComponentScan
public class Application extends WebMvcConfigurerAdapter {
    public static void main(String[] args) {
         ConfigurableApplicationContext context = SpringApplication.run(Application.class);
    }
}

控制器：

@Controller
public class WebController {
    @RequestMapping(value="/")
    public String index(){
        System.out.println("Home Page");
        return "index";
    }
}

索引.html ：

<!DOCTYPE html>
<html lang="en">
<body>
 <h1>Hello</h1>    
</body>
</html>

聚甲醛：

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.App</groupId>
    <artifactId>App</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <name>App</name>
    <description>App</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.1.8.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>   
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>1.4.181</version>
        </dependency>
        <!--dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-redis</artifactId>
        </dependency--> 
        <dependency>
            <groupId>com.firebase</groupId>
            <artifactId>firebase-client</artifactId>
            <version>1.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>2.10.4</version>
        </dependency>
    </dependencies>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <start-class>App.Application</start-class>
        <java.version>1.7</java.version>
    </properties>

    <repositories>
        <repository>
            <id>spring-releases</id>
            <name>Spring Releases</name>
            <url>http://repo.spring.io/libs-release</url>
        </repository>
    </repositories>

    <pluginRepositories>
        <pluginRepository>
            <id>spring-releases</id>
            <name>Spring Releases</name>
            <url>http://repo.spring.io/libs-release</url>
        </pluginRepository>
    </pluginRepositories>   

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

答案 1

看起来你的班级道路上没有Thymeleaf。

添加此依赖项：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

然后一切都应该工作。

如果您仍然遇到一些问题，我建议您使用 http://start.spring.io/ 创建新项目。

答案 2

点击此链接。给出的 http://spring.io/guides/gs/handling-form-submission/ 个很好的例子

src/main/java/hello/GreetingController.java

package hello;
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) {
        return "result";
    }
}

src/main/resources/templates/greeting.html

<html xmlns:th="http://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>

src/main/resources/templates/result.html

<!DOCTYPE HTML>
<html xmlns:th="http://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>

src/main/java/hello/Application.java

package hello;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

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

}