Spring - 如何正确使用@Autowired来防止controller / MockMvc为空？

我正在尝试运行一些单元测试并遇到一个问题，我确信该问题源于对自动装配的误解。我有一个单元测试类，我正在尝试使用@Autowired在 MockMvc 和 REST 控制器上——两者最终都为 null。

我看到一些消息来源试图解释为什么会发生这种情况（包括这个更多 更少 帖子 https://www.moreofless.co.uk/spring-mvc-java-autowired-component-null-repository-service/和一个乐于助人的StackOverflow 帖子 https://stackoverflow.com/questions/19896870/why-is-my-spring-autowired-field-null这给了我一些见解，但并没有完全帮助我解决我的问题）。

下面是我为重现此问题而制作的示例项目的相关源代码。

ManagerControllerTest.java

@RunWith(SpringRunner.class)
@WebMvcTest(ManagerController.class)
public class ManagerControllerTest {
    @Autowired
    private MockMvc mockMvc;

    @MockBean
    private Manager manager;

    @Autowired
    private ManagerController controller;

    @Test
    public void controllerNotNull() throws Exception {
        assertThat(controller).isNotNull();
    }

    @Test
    public void testStoreSomething() throws Exception {
        String path = "/manager/store-something/";

        MockHttpServletRequestBuilder builder = MockMvcRequestBuilders.get(path)
                    .characterEncoding("UTF-8")
                    .contentType(MediaType.APPLICATION_JSON);

        MvcResult result = mockMvc.perform(builder).andReturn();
        assertEquals(HttpStatus.CREATED, result.getResponse().getStatus());
    }
}

The controllerNotNull()测试结果在

java.lang.AssertionError：期望实际不为空

不过，奇怪的是，当我用 Java 创建一个新的 Gradle 项目并将本文中的示例代码导入其中时，controllerNotNull() passes.

And testStoreSomething()结果是

java.lang.NullPointerException 位于 com.example.sandbox.rest.ManagerControllerTest.testStoreSomething(ManagerControllerTest.java:46)

这里存在一个问题：我误解了什么？我究竟做错了什么？我可以删除@Autowired从控制器并实例化它new ManagerController()但我留下了 MockMvc 问题。

ManagerController.java

@Controller
@RequestMapping(value = "/manager/")
public class ManagerController {
    Manager manager = new Manager(new StringStorage());

    @PostMapping(value = "store-something")
    private ResponseEntity<?> storeSomething(String str) {
        manager.storeSomething(str);
        return new ResponseEntity<>(CREATED);
    }
}

管理器.java

public class Manager {
    private final Storage storage;

    public Manager(Storage storage) {
        this.storage = storage;
    }

    public void storeSomething(String str) {
        storage.store(str);
    }
}

存储.java

public interface Storage {
    void store(String str);
}

字符串存储.java

public class StringStorage implements Storage {
    Map<String, String> stringMap;

    @Override
    public void store(String str) {
        stringMap.put(str, str);
    }
 }

应用程序.java

@SpringBootApplication
public class Application {

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

}

构建.gradle已对原始帖子进行编辑（以使用 JUnit4），但问题仍然存在。

repositories {
    jcenter()
}

apply plugin: 'java'
apply plugin: 'eclipse'

dependencies {
 compile group: 'org.springframework.boot', name: 'spring-boot-starter-web', version: '2.0.0.RELEASE'
    compile group: 'org.springframework.boot', name: 'spring-boot-starter-tomcat', version: '2.0.0.RELEASE'

    testCompile group: 'org.springframework.boot', name: 'spring-boot-starter-test', version: '2.0.0.RELEASE'
    testImplementation 'org.junit.jupiter:junit-jupiter-api:4.0.0'
    testImplementation 'org.junit.jupiter:junit-jupiter-params:4.0.0'
    testCompile group: 'org.mockito', name: 'mockito-core', version: '2.17.0'
    testCompile group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: "4.0.0"
    testCompile group: 'org.junit.platform', name: 'junit-platform-launcher', version: "1.3.1"
}

@RestController
@RequestMapping(value = "/manager")
public class ManagerController {

    @Autowired
    Manager manager;

    @PostMapping(value = "/store-something")
    private ResponseEntity<?> storeSomething(String str) {
        manager.storeSomething(str);
        return new ResponseEntity<>(CREATED);
    }
}


@Component
public class Manager {

    @Autowired
    private Storage storage;

    public void storeSomething(String str) {
        storage.store(str);
    }
}


public interface Storage {
    void store(String str);
}

@Service
public class StringStorage implements Storage {
    Map<String, String> stringMap = new HashMap<>();

    @Override
    public void store(String str) {
        stringMap.put(str, str);
    }
 }




@SpringBootApplication
public class Application {

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

}

测试类：

@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureMockMvc
public class ApplicationTest {

    @Autowired
    private MockMvc mockMvc;

    @Test
    public void shouldReturnDefaultMessage() throws Exception {
        this.mockMvc.perform(post("/manager/store-something")).andDo(print()).andExpect(status().isOk())
                .andExpect(content().string(containsString("Hello World")));
    }
}