java - Spring Boot 应用程序在运行时可以运行，但在测试时会崩溃

Question

我有一个带有一个 Controller 的简单 Spring 应用程序

@RestController
public class UserController {

//  @Autowired
//  UserServiceImpl userService;

  @RequestMapping(value="/getUser", method = RequestMethod.GET)
  public String getUser(){
//    return userService.greetUser();
    return "Hello user";
  }

当我启动它时它就起作用了。如果我取消注释 @Autowired 并使用 UserService 运行第一个 return 语句，它也可以工作。

我的服务界面

@Service
public interface UserService {
  String greetUser();
  void insertUsers(List<User> users);
}

和实现

@Service
public class UserServiceImpl implements UserService{

  @Override
  public String greetUser() {
    return "Hello user";
  }
}

但是当我测试它时，该应用程序出现以下错误

java.lang.IllegalStateException: Failed to load ApplicationContext
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userController': Unsatisfied dependency expressed through field 'userService'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.example.demo.service.UserServiceImpl' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.example.demo.service.UserServiceImpl' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

测试类

@RunWith(SpringRunner.class)
@WebMvcTest
public class DemoApplicationTests {

  @Autowired
  private MockMvc mockMvc;

    @Test
  public void shouldReturnHelloString() throws Exception{
      this.mockMvc
      .perform(get("/getUser"))
      .andDo(print())
      .andExpect(status().isOk())
      .andExpect(content().string("Hello user"));
  }
}

另外，如果我删除

//  @Autowired
//  UserServiceImpl userService;

并使用第二个返回语句运行测试，测试执行没有错误。我知道问题出在 UserServiceImpl 中，但我不知道问题是什么。我需要纠正什么？

Answer 1

您应该尝试通过接口(interface)而不是实现来 Autowiring 您的 bean

@Autowired
UserService userService;

而且您还应该从 UserService 接口(interface)中删除 @Service