为什么我要让404弹簧靴休息一下

Question

I am implementing rest services with Spring Boot. The entity classes are defined in a separate package. So I added that with Component annotation in Application.java.

@Configuration
@EnableAutoConfiguration
@ComponentScan("org.mdacc.rists.cghub.model")
@EnableJpaRepositories(basePackages = "org.mdacc.rists.cghub.model") 
public class Application 
{
    public static void main( String[] args )
    {
        SpringApplication.run(Application.class, args);
    }
}

Here is my controller class:

// SeqController.java
@RestController
public class SeqController {

    @Autowired
    private SeqService seqService;
    @RequestMapping(
            value = "/api/seqs", 
            method = RequestMethod.GET, 
            produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<List<SeqTb>> getSeqs() {
        List<SeqTb> seqs = seqService.findAll();

        return new ResponseEntity<List<SeqTb>>(seqs, HttpStatus.OK);
    }
}

I also created a JPA data repository that extends JPARepository in which I added custom query code.

// SeqRepository.java
@Repository
public interface SeqRepository extends JpaRepository<SeqTb, Integer> {

    @Override
    public List<SeqTb> findAll();

    @Query("SELECT s FROM SeqTb s where s.analysisId = :analysisId")
    public SeqTb findByAnalysisId(String analysisId);
}

Below is the servicebean class that implements a service interface

// SeqServiceBean.java
@Service
public class SeqServiceBean implements SeqService {
    @Autowired
    private SeqRepository seqRepository;

    @Override
    public List<SeqTb> findAll() {
        List<SeqTb> seqs = seqRepository.findAll();
        return seqs;
    }

    public SeqTb findByAnalysisId(String analysisId) {
        SeqTb seq = seqRepository.findByAnalysisId(analysisId);
        return seq;
    }
}

When I started the application and type the following url in the browser " http://localhost:8080/api/seqs " , I got 404 error. What did I miss?

Edit #1: I decided to take out the JPA repository stuff and change the controller class to the following:

@RestController
//@RequestMapping("/")
public class SeqController {
    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();
        g1.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);

    }
}

When I started the application and put "localhost:8080/api/greetings" in my browser I still got 404.

Answer 1

If spring boot starter web is not there in your pom.xml then add the same as the reason could be the code not being able to map the endpoints.

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

Answer 2

==>Did you make sure that your Spring Boot application class and your Rest Controller are in the same base package? For Example if your package for Spring Boot application class is com.example.demo, then your Rest Controller should be in same base package as com.example.demo.controller.

==>I think that is the reason boot is unable to map to the uri of your rest controller. Because @SpringBootApplication has @ComponentScan and @Configuration embedded in it already. Try doing this. I hope it works.

Answer 3

The first thing I would try is to put @RequestMapping("/") on the class definition of the controller. Keep the same value on the method.

Another thing, unrelated to your problem, is that you do not need to define that custom query. JPA is actually smart enough to do the query you defined just by using that method name. Check out the findByLastName example here: https://spring.io/guides/gs/accessing-data-jpa/ .