WebTestclient 正在抛出 Null 异常艰难的@Autowire 在那里

Question

该项目是 spring 启动应用程序。 当尝试从测试用例中作为 webtestclient 访问 api 时，它会抛出空点异常。

class 和 Restcontroller an 和 testclass 如下

这是 class

@Component
public class GetMessage {
@Async
public void fetchData( fileType Type, String requestBody) {

        switch (A) {
            case a:
                operation(requestBody);
             break;
            case b:
                 // do some Operation
            break;
            default:
             break;
         }
 }
}

Rest controller

@RestController()
@RequestMapping("api/school/student-receiver/assignment")
public class  FileReceiverRestController {

@Autowired
    private objectMapper mapper;

@PostMapping(path = "/file", consumes = "application/json")
public ResponseEntity<String> receivefile(@RequestBody String reqBody) {        

    mapper.fetchData(fileType.A ,String reqBody);

    return new ResponseEntity<>(CALL_RESP, HttpStatus.OK);
}

测试 class

@AutoConfigureWebTestClient
public class E2ETest {

  @Autowired
    private WebTestClient webTestClient ;

   String ReceiverUrl="api/school/student-receiver/assignment/file"

     @Test
     pubilic void Testapi()
    {
    webTestClient  //====> facing null exception
            .post().uri(ReceiverUrl)
            //.header("Content-Type", "application/json")
            .contentType(MediaType.APPLICATION_JSON)
            .bodyValue(requestPayload)
            .accept(MediaType.APPLICATION_JSON)
            .exchange()
            // then
            .expectStatus().isEqualTo(HttpStatus.OK);
  }
   }

java.lang.NullPointerException at E2ETest.Testapi(E2ETest.java:176) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl .java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at org. junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallabl e.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit .runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) at org. junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.Z93F725A07423FE1C889 F448B33D21F46Z:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate (ParentRunner.java:268) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.junit.runner.JUnitCore.run(JUnitCore.java:137) at com.intellij.junit4.JUnit4IdeaTestRunner. startRunnerWithArgs(JUnit4IdeaTestRunner.java:68) at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33) at Z4D236D9A2D102C5FE6AD1C50D A4BEC50Z.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230) at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)

Answer 1

根据我对Spring引导项目的理解，使用@AutoconfigureWebTestClient仅在测试 WebFlux 应用程序时才有效。 当您使用 Spring MVC (Tomcat) 并且只想使用WebClient / WebTestClient时，这可能是原因。

@AutoconfigureWebTestClient的 Javadoc 也对此添加了提示：

/**
 * Annotation that can be applied to a test class to enable a {@link WebTestClient}. At
 * the moment, only WebFlux applications are supported.
 *
 * @author Stephane Nicoll
 * @since 2.0.0
 * @see WebTestClientAutoConfiguration
 */

尽管如此，有效的是使用@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)进行测试。 这将确保在后台自动配置TestRestTemplate和WebTestClient ：

// if you are using JUnit 4 this is also needed
// @RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class WebTestClientAccessTest {

  @Autowired
  private WebTestClient webTestClient;

  @Autowired
  private TestRestTemplate testRestTemplate;

  @Test
  public void notNull() {
    assertNotNull(webTestClient);
    assertNotNull(testRestTemplate);
  }
}

这将启动整个 Spring 上下文，您可以使用客户端从外部访问您的应用程序。

如果您不想启动嵌入式 Tomcat 并加载所有 bean，您可以查看@WebMvcTest以专注于测试您的 web 层。 为此，您将使用MockMvc并使用模拟的 servlet 环境。 Spring Boot 的此入门指南提供了很好的介绍。

更多信息可以在Spring 引导文档中找到。