Question

我的主课是这样的：

package com.ratings.main;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class App {
    public static void main( String[] args ) {
        SpringApplication.run(App.class, args);
        System.out.println( "Hello World!" );
    }
}

package com.ratings.controller;
@RestController
public class PollController {

    @Autowired
    Poll poll;

    @GetMapping("/")
    public String home() {
        System.out.println("home " + "HOME");
        return "Home";
    }
}

和pom.xml文件：

<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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.ratings.main.App</groupId>
  <artifactId>Ratings</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>Ratings</name>
  <url>http://maven.apache.org</url>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.5.RELEASE</version>
  </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-actuator</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-devtools</artifactId>
      <optional>true</optional>
    </dependency>

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

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <executions>
          <execution>
            <goals>
              <goal>repackage</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <mainClass>com.ratings.main.App</mainClass>
          <excludeDevtools>false</excludeDevtools>
        </configuration>
      </plugin>
    </plugins>
  </build>

</project>

当我尝试http://localhost:9090/时得到404。为什么它不返回字符串“ Home”？

Answer 1

您的SpringBootApplication类在软件包中：

package com.ratings.main;

您的控制器在

package com.ratings.controller;

控制器必须与SpringBootApplication相同或在其下方。

所以将SpringBootApplication移至

com.ratings

或将控制器移至

com.ratings.main.controller

Answer 2

将您的控制器类放入此软件包com.ratings.main中。 @SpringApplication包含@ComponentScan。该注释从主程序包及其子组中扫描您的bean和配置。

Answer 3

@SpringBootApplication软件包：com.ratings.main;

@Controller软件包：com.ratings.controller;

controller class必须与用@SpringBootApplication注释的主类位于同一类或以下。您可以通过添加示例包来解决此问题； com.ratings.main.*;相同或以下。

另一方面，您可以将@ComponentScan用于控制器软件包。

@ComponentScan(value = {"your.controller.package"})

@SpringBootApplication已具有此标签，但仅扫描相同顺序及以下的顺序。

Spring Boot Rest API返回404

3 个答案: