SpingBoot映射不工作。404状态

Question

我在youtube上按部就班地学习教程，但我没有得到结果。代码如下：

主要应用

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

public class Greeting {

    private BigInteger id;
    private String text;

    public Greeting() {}

    public BigInteger getId() {
        return id;
    }

    public void setId(BigInteger id) {
        this.id = id;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }
}

@RestController()
public class GreetingController {

    private static BigInteger nextId;
    private static Map<BigInteger, Greeting> greetingMap;

    private static Greeting save(Greeting greeting) {
        if (greetingMap == null) {

            greetingMap = new HashMap<BigInteger, Greeting>();
            nextId = BigInteger.ONE;
        }
        greeting.setId(nextId);
        nextId = nextId.add(BigInteger.ONE);
        greetingMap.put(greeting.getId(), greeting);
        return greeting;
    }

    static {
        Greeting g1 = new Greeting();
        g1.setText("Hello World");
        save(g1);
        Greeting g2 = new Greeting();
        g2.setText("Hola Mundo!");
        save(g2);
    }

    @RequestMapping(
            value = "/api/greetings",
            method = RequestMethod.GET,
            produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<Collection<Greeting>> getGreetings() {
        Collection<Greeting> greetings = greetingMap.values();

        return new ResponseEntity<Collection<Greeting>>(greetings, HttpStatus.OK);
    }
}

<modelVersion>4.0.0</modelVersion>

<groupId>com.hakeem.webservice2</groupId>
<artifactId>WebService2</artifactId>
<version>0.0.1-SNAPSHOT</version>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.2.1.RELEASE</version>
</parent>

<dependencies>

    <dependency>

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

    </dependency>

</dependencies>

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

</build>

{
    "timestamp": 1439128293727,
    "status": 404,
    "error": "Not Found",
    "message": "No message available",
    "path": "/api/greetings"
}

或来自Chrome的以下内容：

白标签错误页

此应用程序没有/error的显式映射，因此您将其视为一种后退。

Answer 1

给定的代码在我看来是正确的。查看完整的源代码可能会有所帮助。例如-如果greetingcontroller类不在application类的同一包或子包中，则不会扫描它，因此您将出现此错误。