如果与 ClientHttpRequestInterceptor 一起使用，Spring Resttemplate postforobject 返回 null 作为对象响应

Question

我正在尝试使用休息服务，并且我正在使用 Spring RestTemplate postForObjectMethod 发布一些数据，但我得到一个空响应，即使我可以在有效负载中看到请求和响应。

[更新] 我正在使用实现 ClientHttpRequestInterceptor 的拦截器，如果我删除它，我会收到响应。

[PS：服务被配置为 POST，理想情况下它应该是 GET，原因很明显，但我仍然很好奇为什么没有响应作为帖子的一部分，即使我可以在 http 日志中看到相同的内容。]

配置基于 Spring MVC 4 的应用程序

应用上下文：

 <bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
        <property name="messageConverters">
            <list>
                <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>
            </list>
        </property>
        <property name="interceptors">
            <list>
                <bean class="com.sipl.interceptors.LoggingRequestInterceptor" />
            </list>
        </property>
</bean>

杰克逊POM

<dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>${jackson.version}</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-annotations</artifactId>
        <version>${jackson.version}</version>
    </dependency>


    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>${jackson.version}</version>
    </dependency>

拦截器类

public class LoggingRequestInterceptor implements ClientHttpRequestInterceptor {

    final static Logger logger = LoggerFactory.getLogger(LoggingRequestInterceptor.class);

    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {

        traceRequest(request, body);
        ClientHttpResponse response = execution.execute(request, body);
        traceResponse(response);
        return response;
    }

    private void traceRequest(HttpRequest request, byte[] body) throws IOException {
        logger.debug("===========================request begin================================================");

        logger.debug("URI : " + request.getURI());
        logger.debug("Method : " + request.getMethod());
        logger.debug("Request Body : " + new String(body, "UTF-8"));
        logger.debug("==========================request end================================================");
    }

    private void traceResponse(ClientHttpResponse response) throws IOException {
        StringBuilder inputStringBuilder = new StringBuilder();
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(response.getBody(), "UTF-8"));
        String line = bufferedReader.readLine();
        while (line != null) {
            inputStringBuilder.append(line);
            inputStringBuilder.append('\n');
            line = bufferedReader.readLine();
        }
        logger.debug("============================response begin==========================================");
        logger.debug("status code: " + response.getStatusCode());
        logger.debug("status text: " + response.getStatusText());
        logger.debug("Response Body : " + inputStringBuilder.toString());
        logger.debug("=======================response end=================================================");
    }

}

GetAllEmployeesClass

public class GetAllEmployeesVO {
    private ResponseVO response;
    private List<EmployeeBean> employees;
    private String actionCode;

    public String getActionCode() {
        return actionCode;
    }

    public void setActionCode(String actionCode) {
        this.actionCode = actionCode;
    }

    public ResponseVO getResponse() {
        return response;
    }

    public void setResponse(ResponseVO response) {
        this.response = response;
    }

    public List<EmployeeBean> getEmployees() {
        return employees;
    }

    public void setEmployees(List<EmployeeBean> employees) {
        this.employees = employees;
    }
}

控制器

@RestController
public class RestAdminstrationController {
    @Autowired
    private RestTemplate restTemplate;
    @Value("${rest.getallemployees.api.endpoint}")
    private String getEmpEndpt;

    @RequestMapping(value = AppConstatants.GET_EXISTING_APP_USERS, method = RequestMethod.POST)

    public List<EmployeeBean> loadAppAdminUsers(@RequestBody GetAllEmployeesVO userData) {

        try {
            //get Rest Service Data
            GetAllEmployeesVO resp= restTemplate.postForObject(getEmpEndpt,userData,GetAllEmployeesVO.class);
            //resp is coming as null

请求响应 HTTP 负载日志：

2015-12-12 15:45:53 DEBUG RestTemplate:79 - Created POST request for "http://103.35.123.23:8080/siplrestservices/sipl/EmployeeService/getAllEmployees"
2015-12-12 15:45:53 DEBUG RestTemplate:720 - Setting request Accept header to [application/json, application/*+json]
2015-12-12 15:45:53 DEBUG RestTemplate:797 - Writing [com.sipl.common.beans.GetAllEmployeesVO@1dd42575] using [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter@52e7339f]
2015-12-12 15:45:53 DEBUG LoggingRequestInterceptor:36 - ===========================request begin================================================
2015-12-12 15:45:53 DEBUG LoggingRequestInterceptor:38 - URI : http://xxxxx:8080/siplrestservices/sipl/EmployeeService/getAllEmployees
2015-12-12 15:45:53 DEBUG LoggingRequestInterceptor:39 - Method : POST
2015-12-12 15:45:53 DEBUG LoggingRequestInterceptor:40 - Request Body : {"response":null,"employees":null,"actionCode":"M"}
2015-12-12 15:45:53 DEBUG LoggingRequestInterceptor:41 - ==========================request end================================================
2015-12-12 15:45:54 DEBUG LoggingRequestInterceptor:53 - ============================response begin==========================================
2015-12-12 15:45:54 DEBUG LoggingRequestInterceptor:54 - status code: 201
2015-12-12 15:45:54 DEBUG LoggingRequestInterceptor:55 - status text: Created
2015-12-12 15:45:54 DEBUG LoggingRequestInterceptor:56 - **Response Body : {"employees":[{"commonName":"MOHAN KUMAR GHOSHAL","countryCode":"","dateOfJoining":"2015-11-23","designationId":"4","division":"GENERAL","emailId":"","employeeId":"1","employeeNo":"M-392","employeeStatus":"1","hqCityId":"2","lastWorkingDate":"2015-11-23","mobile":{"mobileStatus":"1"},"mobileNo":"1234567890"}],"response":{"respCd":"0","respDesc":"SUCCESS"}}**

2015-12-12 15:45:54 DEBUG LoggingRequestInterceptor:57 - =======================response end=================================================
2015-12-12 15:45:54 DEBUG RestTemplate:632 - POST request for "http://xxxxx:8080/siplrestservices/sipl/EmployeeService/getAllEmployees" resulted in 201 (Created)

Answer 1

您可以使用 BufferingClientHttpRequestFactory。 它允许多次读取响应。

Answer 2

按照 Nati 的建议，我对我的 rest 模板进行了以下更改，效果非常好。

<bean id="SimpleClientHttpRequestFactory" class="org.springframework.http.client.SimpleClientHttpRequestFactory"/>
<bean id="BufferingClientHttpRequestFactory" class="org.springframework.http.client.BufferingClientHttpRequestFactory">
    <constructor-arg ref="SimpleClientHttpRequestFactory"/>
</bean>

<bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
    <constructor-arg ref="BufferingClientHttpRequestFactory"/>
    <property name="messageConverters">
        <list>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>
        </list>
    </property>
    <property name="interceptors">
        <list>
            <bean class="com.sipl.interceptors.LoggingRequestInterceptor" />
        </list>
    </property>
</bean>