java - 使用 HttpComponentsClientHttpRequestFactory 在 RestTemplateBuilder 中添加自定义 ClientHttpRequestInterceptor

Question

我需要在所有 RestTemplate 客户端请求中添加一个自定义 header 。所以我实现了 ClientHttpRequestInterceptor。然后我在我的 RestTemplateBuilder 配置中添加拦截器，如下所示。问题是，当 RestTemplate 进行 HTTP 调用时，它抛出以下异常:

java.lang.ClassCastException: org.springframework.http.client.InterceptingClientHttpRequestFactory cannot be cast to org.springframework.http.client.HttpComponentsClientHttpRequestFactory

RestTemplate Bean 创建:

@Bean
  public RestTemplate restTemplate(RestTemplateBuilder restTemplateBuilder) {
    PoolingHttpClientConnectionManager poolingConnectionManager = new PoolingHttpClientConnectionManager();
    poolingConnectionManager.setMaxTotal(restTemplateProps.getMaxConnectionsPerPool());
    poolingConnectionManager.setDefaultMaxPerRoute(restTemplateProps.getMaxDefaultConnectionPerRoute());
    CloseableHttpClient client = HttpClientBuilder.create().setConnectionManager(poolingConnectionManager).build();
    ClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory(client);
    restTemplateBuilder = restTemplateBuilder.additionalInterceptors(new MyClientHttpRequestInterceptor());
    return restTemplateBuilder.requestFactory(clientHttpRequestFactory).build();
  }

此外，我稍后会在下面的代码中更新超时:

  protected void setRestTemplateTimeouts() {

    HttpComponentsClientHttpRequestFactory rf =
        (HttpComponentsClientHttpRequestFactory) restTemplate.getRequestFactory();
    rf.setConnectTimeout(restTemplateProps.getConnectionTimeout());
    rf.setReadTimeout(restTemplateProps.getSocketTimeout());
  }

谁能帮我解决这个问题？

Answer 1

问题是，我试图在设置 ClientHttpRequestInterceptor 之后设置连接和读取超时。

在我的 setRestTemplateTimeouts() 方法中，当我尝试获取并将 requestFactory 类型转换为 HttpComponentsClientHttpRequestFactory 时，我得到了 ClassCastException 异常，因为 restTemplate.getRequestFactory() 返回 InterceptingClientHttpRequestFactory 而不是 HttpComponentsClientHttpRequestFactory。这是因为我在我的 restTemplate 对象中添加了一个拦截器。

解决办法是设置超时前设置拦截器，因为设置拦截器后不能设置超时。引用以下代码:

@Bean
  public RestTemplate restTemplate(RestTemplateBuilder restTemplateBuilder) {
    PoolingHttpClientConnectionManager poolingConnectionManager = new PoolingHttpClientConnectionManager();
    poolingConnectionManager.setMaxTotal(restTemplateProps.getMaxConnectionsPerPool());
    poolingConnectionManager.setDefaultMaxPerRoute(restTemplateProps.getMaxDefaultConnectionPerRoute());
    CloseableHttpClient client = HttpClientBuilder.create().setConnectionManager(poolingConnectionManager).build();
    HttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory(client);
    clientHttpRequestFactory.setConnectTimeout(restTemplateProps.getConnectionTimeout());
    clientHttpRequestFactory.setReadTimeout(restTemplateProps.getSocketTimeout());
    restTemplateBuilder = restTemplateBuilder.additionalInterceptors(new MyClientHttpRequestInterceptor());
    return restTemplateBuilder.requestFactory(clientHttpRequestFactory).build();
  }