java - @RequestMapping spring boot 无法按预期运行
问题描述
我正在尝试创建一个简单的应用程序,将“Hello World”打印到端口 8080
这是我的主要java类:
package com.iz.backend;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
@SpringBootApplication
public class BackendApplication {
@RequestMapping("/")
public String helloWorld() {
return "Hello World";
}
public static void main(String[] args) {
SpringApplication.run(BackendApplication.class, args);
}
}
代码编译并且应用程序成功构建但是当我去 localhost:8080
我收到 404 错误:
Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.
Mon Jan 11 21:18:51
There was an unexpected error (type=Not Found, status=404).
我的 pom.xml 有什么问题吗?这是pom文件:
<?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>2.4.1</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.iz</groupId>
<artifactId>backend</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>backend</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>11</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-source-plugin</artifactId>
<version>2.4</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
解决方案
添加到@Reimeus的答案,
确保将MyController
class 和BackendApplication
class 保留在主包中,即com.iz.backend
.
|-src/main/java
|--com.iz.backend
|--controllers
|--MyController
|--BackendApplication
或者,使用 basePackages:
@SpringBootApplication(scanBasePackages = {"com.iz.backend"})
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