使用RestTemplate模拟Postman请求失败，求解决方案

我尝试从https://ws-public.interpol.int/notices/v1/red获取JSON数据，该请求在Postman中可正常运行：

但当我使用Spring的RestTemplate按如下代码（尝试完全复制请求头）模拟时：

final HttpHeaders headers = new HttpHeaders();

headers.set(HttpHeaders.CACHE_CONTROL, "no-cache");
headers.set(HttpHeaders.USER_AGENT, "PostmanRuntime/7.42.0");
headers.set(HttpHeaders.HOST, "ws-public.interpol.int");
headers.set(HttpHeaders.ACCEPT, "*/*");
headers.set(HttpHeaders.ACCEPT_ENCODING, "gzip, deflate, br");
headers.set(HttpHeaders.CONNECTION, "keep-alive");

final HttpEntity<Void> entity = new HttpEntity<>((Void) null, headers);

final RestTemplate restTemplate = new RestTemplateBuilder()
    .setConnectTimeout(Duration.ofMillis(5000L))
    .setReadTimeout(Duration.ofMillis(5000L))
    .build();

final String response = restTemplate
    .exchange(URL, HttpMethod.GET, entity, String.class)
    .getBody();

请求失败并返回403 Forbidden：

Exception in thread "main" org.springframework.web.client.HttpClientErrorException$Forbidden: 403 Forbidden: "<HTML><HEAD><LF><TITLE>Access Denied</TITLE><LF></HEAD><BODY><LF><H1>Access Denied</H1><LF> <LF>You don't have permission to access "http&#58;&#47;&#47;ws&#45;public&#46;interpol&#46;int&#47;" on this server.<P><LF>Reference&#32;&#35;18&#46;1cf95568&#46;1730991641&#46;2abc645d<LF><P>https&#58;&#47;&#47;errors&#46;edgesuite&#46;net&#47;18&#46;1cf95568&#46;1730991641&#46;2abc645d</P><LF></BODY><LF></HTML><LF>"
    at org.springframework.web.client.HttpClientErrorException.create(HttpClientErrorException.java:109)
    at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:168)
    at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:122)
    at org.springframework.web.client.ResponseErrorHandler.handleError(ResponseErrorHandler.java:63)
    at org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:819)
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:777)
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:711)
    at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:602)
    at com.company.sample.MySampleApp.main(MySampleApp.java:55)

请问如何成功模拟Postman的请求？我遗漏了哪些配置？

出现403 Forbidden通常是因为RestTemplate的请求与Postman的请求存在细节差异，服务器的验证或反爬机制拒绝了请求，可按以下步骤修复：

1. 移除手动设置的HOST头 #

RestTemplate会自动根据请求URL生成正确的HOST头，手动设置可能导致格式或值的不一致，直接删除headers.set(HttpHeaders.HOST, "ws-public.interpol.int");这行代码。

2. 完整复制Postman的所有请求头 #

Postman会自动添加一些隐藏的请求头，你需要把这些头也加入到RestTemplate的HttpHeaders中：

• 在Postman的请求页面，点击Headers选项卡，勾选"Show auto-generated headers"，查看所有发送的头信息
• 将所有头（比如Accept-Language、DNT、Postman-Token等）逐一添加到代码的HttpHeaders里

3. 更换请求工厂为Apache HttpClient #

RestTemplate默认使用的SimpleClientHttpRequestFactory兼容性有限，换成Apache HttpClient可以更好地模拟Postman的请求行为：
首先引入Maven依赖：

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.14</version>
</dependency>

然后修改RestTemplate的构建代码：

import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;

// ...

CloseableHttpClient httpClient = HttpClientBuilder.create()
        .build();

ClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(httpClient);

RestTemplate restTemplate = new RestTemplateBuilder()
        .setConnectTimeout(Duration.ofMillis(5000L))
        .setReadTimeout(Duration.ofMillis(5000L))
        .requestFactory(() -> requestFactory)
        .build();

4. 检查并添加Cookie（如果需要） #

Postman会自动保存服务器返回的Cookie，后续请求会自动携带。你可以在Postman的Response Headers中查看Set-Cookie字段，然后在RestTemplate中手动添加Cookie头：

headers.add("Cookie", "替换为Postman中获取到的Cookie内容");

完成以上步骤后，重新发起请求，即可和Postman一样正常获取数据。

内容的提问来源于stack exchange，提问作者Hasan Can Saral