spring 现场服务需要一个 bean 类型

Question

I'm working on Spring over Hibernate project an i'm only in the beginning. I'm trying to have a SpringBootApplication which writes to MySql some Location objects. But every time i'm faceing some error. I did everything from my end refer everything still can't resolve it. Please help me out. This is my error

---

APPLICATION FAILED TO START
***************************

Description:

Field service in com.project.abhishek.location.controller.LocationController 
required a bean of type'com.project.abhishek.location.service.LocationService' that could not be 
found.


Action:

Consider defining a bean of type'com.project.abhishek.location.service.LocationService' in your configuration.

Application class

@SpringBootApplication
@ComponentScan(basePackages= {"com.project.abhishek.location.controller"})
@EntityScan(value ="com.project.abhishek.location.entity")
@EnableJpaRepositories(basePackages = {"com.project.abhishek.location.repos"})

public class StudentApplication {

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

Controller

@Controller
public class LocationController {

@Autowired
private LocationService service;

@RequestMapping("/saveLoc")
public String saveLocation(@ModelAttribute("location") Location location, ModelMap modelMap) {
    Location locationSaved = getService().saveLocation(location);

    String msg = "Location save with id:" +locationSaved.getId();
    modelMap.addAttribute("msg", msg);
    return "createLocation";
}

public LocationService getService() {
    return service;
}

public void setService(LocationService service) {
    this.service = service;
}

Service Class

@Service
public class LocationServiceImpl implements LocationService {

@Autowired
private LocationRepos locationRepos;

@Override
public Location saveLocation(Location location) {

    return locationRepos.save(location);
}

@Override
public Location updateLocation(Location location) {
    return locationRepos.save(location);
}

@Override
public void deleteLocation(Location location) {
    locationRepos.delete(location);
}

@Override
public Location getLocation(int id) {
    Optional<Location> optional = locationRepos.findById(id);
    Location location = optional.get();
    return location;
}

@Override
public List<Location> getAllLocation() {
    return locationRepos.findAll();
}

public LocationRepos getLocationRepos() {
    return locationRepos;
}

public void setLocationRepos(LocationRepos locationRepos) {
    this.locationRepos = locationRepos;
}

}

Entity

@Entity
public class Location {

@Id
private int id;
private String code;
private String name;
private String type;

public int getId() {
    return id;
}

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

public String getCode() {
    return code;
}

public void setCode(String code) {
    this.code = code;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getType() {
    return type;
}

public void setType(String type) {
    this.type = type;
}

@Override
public String toString() {
    return "Location [id=" + id + ", code=" + code + ", name=" + name + ", type=" + type + "]";
}

My packages structure are

com.project.abhishek.location---application classs  
com.project.abhishek.location.controller---controller class  
com.project.abhishek.location.entity---entity class  
com.project.abhishek.location.repos---repository class  
com.project.abhishek.location.service---service class 

Answer 1

Just include com.project.abhishek.location.service in your @ComponentScan or simply delete @ComponentScan (this way it will scan spring boot application package com.project.abhishek.location and all packages below it).

By defining @ComponentScan(basePackages= {"com.project.abhishek.location.controller"}) you overrode default component scan path com.project.abhishek.location and told spring to only scan com.project.abhishek.location.controller and packages below it, so it didn't scan com.project.abhishek.location.service .

Check this https://dzone.com/articles/spring-spring-boot-and-component-scan for more details on defining @ComponentScan . This is similar to your situation:

However, let's say one of the components is defined in package com.in28minutes.springboot.somethingelse

In this case, you would need to add the new package into Component Scan.

You have two options:

Define @ComponentScan(“com.in28minutes.springboot”) This would scan the entire parent tree of com.in28minutes.springboot.

Or define two specific Component Scans by using an array. @ComponentScan({“com.in28minutes.springboot.basics.springbootin10steps”,”com.in28minutes.springboot.somethingelse”})

Answer 2

Nothing is required in Spring Boot, it's already there, @SpringBootApplication is sufficient.

Just make below changes and you will be good to go.

Main Application Class:

@SpringBootApplication
public class StudentApplication {

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

Controller Class: @Autowired is sufficient load your dependency, don't need to set, just see change you need to make in @Service notation where you need to name the interface name so dependency name can be locationService when you auto wired.

@RestController
public class LocationController {

@Autowired
private LocationService service;

@RequestMapping("/saveLoc")
public String saveLocation(@ModelAttribute("location") Location location, ModelMap modelMap) {
    Location locationSaved = getService().saveLocation(location);

    String msg = "Location save with id:" +locationSaved.getId();
    modelMap.addAttribute("msg", msg);
    return "createLocation";
}

Change in Service Class:

@Service("locationService)
public class LocationServiceImpl implements LocationService {