RestTemplate Junit：无法调用"org.springframework.http.ResponseEntity.getBody()"，因为"response"为空

Question

我有一个spring启动应用程序，使用rest模板使其他内部项目的API命中，我正在为它编写单元测试用例，但测试用例如果失败，由于抛出意外异常:java.lang.NullPointerException:无法调用"org.springframework.http.ResponseEntity.getBody()"因为"response"为空

@Service
@Slf4j
public class DynamoDBServiceImpl implements DynamoDBService {
private final RestTemplate restTemplate;
private final HttpHeaders httpHeaders;
private final String jwtHeader;
private final String apiKeyHeader;
private final String dynamodbSysApiKey;
private final String fetchAdminGroupUrl;
public DynamoDBServiceImpl(
RestTemplate restTemplate,
HttpHeaders httpHeaders,
@Value("${header-name.jwt}") String jwtHeader,
@Value("${header-name.api-key}") String apiKeyHeader,
@Value("${dynamodb-sys-api-key}") String dynamodbSysApiKey,
@Value("${dynamodb-fetch-admin-group-url}") String fetchAdminGroupUrl) {
this.restTemplate = restTemplate;
this.httpHeaders = httpHeaders;
this.jwtHeader = jwtHeader;
this.apiKeyHeader = apiKeyHeader;
this.dynamodbSysApiKey = dynamodbSysApiKey;
this.fetchAdminGroupUrl = fetchAdminGroupUrl;
}
@Override
public List<AdminGroupDTO> getAllAdminGroups() {
log.debug("Request to get admin group details with url : {}", fetchAdminGroupUrl);
httpHeaders.set("Accept", MediaType.APPLICATION_JSON_VALUE);
httpHeaders.setContentType(MediaType.APPLICATION_JSON);
httpHeaders.setBearerAuth(CommonUtils.getHeaderFromCurrentHttpRequest(jwtHeader));
httpHeaders.set(apiKeyHeader, dynamodbSysApiKey);
HttpEntity<AdminGroupDTO> request = new HttpEntity<>(httpHeaders);
ResponseEntity<List<AdminGroupDTO>> response =
restTemplate.exchange(fetchAdminGroupUrl, HttpMethod.GET, request, new ParameterizedTypeReference<List<AdminGroupDTO>>() {});
return response.getBody();
}
}

@SpringBootTest(classes = Application.class)
public class DynamoDBServiceTest {
private final RestTemplate restTemplate = Mockito.mock(RestTemplate.class);
private final HttpHeaders httpHeaders = new HttpHeaders();
private final DynamoDBServiceImpl dynamoDBService =
new DynamoDBServiceImpl(
restTemplate, httpHeaders, "Authorization" , "Api-Key", "fake", "https://fake.com");
@Test
void testGetAllAdminGroups() {
List<AdminGroupDTO> adminGroupDTOList = new ArrayList<>();
AdminGroupDTO adminGroupDTO = new AdminGroupDTO();
adminGroupDTO.setAdminGroupId(1L);
adminGroupDTO.setAdminGroupName("fake");
adminGroupDTO.setCountryName("fake");
adminGroupDTOList.add(adminGroupDTO);
ResponseEntity<List<AdminGroupDTO>> responseEntity = new ResponseEntity<>(adminGroupDTOList, HttpStatus.OK);
when(restTemplate.exchange(
ArgumentMatchers.anyString(),
ArgumentMatchers.any(HttpMethod.class),
ArgumentMatchers.any(),
ArgumentMatchers.<Class<List<AdminGroupDTO>>>any()))
.thenReturn(responseEntity);
assertDoesNotThrow(dynamoDBService::getAllAdminGroups);
}
}

Answer 1

替换这行代码:

when(restTemplate.exchange(
ArgumentMatchers.anyString(),
ArgumentMatchers.any(HttpMethod.class),
ArgumentMatchers.any(),
ArgumentMatchers.<Class<List<AdminGroupDTO>>>any()))
.thenReturn(responseEntity);

With this:

when(restTemplate.exchange(
ArgumentMatchers.anyString(),
ArgumentMatchers.any(HttpMethod.class),
ArgumentMatchers.any(),
ArgumentMatchers.eq(new ParameterizedTypeReference<List<AdminGroupDTO>>() {}))
)
.thenReturn(responseEntity);

异常应该消失。

更多细节可以查看这篇文章。