SpringBoot应用调用myhost.com API陷入等待状态问题求助

我需要调用以下GET API：
https://myhost.com/api/option-chain-indices?symbol=ALL

该接口在浏览器、PostMan等REST客户端中能正常返回结果，但在SpringBoot项目中调用时会陷入无限等待（超过30分钟仍无响应）。项目中调用其他第三方API均正常，仅该域名下的此接口出现问题。

我尝试了两种调用方式均失败：

方式1：HttpURLConnection #

public void myFunction() {

        String output = "";
        Root data = null;

        try {

            URL url1 = new URL("https://myhost.com/api/option-chain-indices?symbol=ALL");
            HttpURLConnection connection1 = (HttpURLConnection) url1.openConnection();
            connection1.setRequestMethod("GET");
            connection1.setRequestProperty("Accept", "application/json");
 
            if (connection1.getResponseCode() != 200) {
                System.out.println("NSE INIT : Failed : HTTP Error code : " + connection1.getResponseCode());
            } else {

                InputStreamReader in = new InputStreamReader(connection1.getInputStream());
                BufferedReader br = new BufferedReader(in);
                while ((output = br.readLine()) != null) {
                    data = objectMapper.readValue(output, Root.class);
                }
            }
            connection1.disconnect();

        } catch (Exception e) {
            System.out.println("Exception" + e);
        }
    }

方式2：WebClient #

@Service
public class MyService {

    private final WebClient webClient;

    public MyService(WebClient.Builder webClientBuilder) {
        this.webClient = webClientBuilder.build();
    }

    public void fetchDataFromAPI() {

        System.out.println("Get Data ....");
        this.webClient.get()
                .uri("https://myhost.com/api/option-chain-indices?symbol=ALL")
                .retrieve()
                .bodyToMono(String.class)
                .subscribe(response -> {
                    // Handle the response here
                    System.out.println("Received response: " + response);
                });

    }
}

请求协助排查问题原因及解决方法。

1. 补充请求头差异 #

浏览器、PostMan会自动携带User-Agent、Accept-Encoding等请求头，部分服务端会依赖这些头判断请求合法性，缺失可能导致响应卡住。

• 给HttpURLConnection添加请求头：

connection1.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36");
connection1.setRequestProperty("Accept-Encoding", "gzip, deflate, br");

• 给WebClient添加请求头：

this.webClient.get()
        .uri("https://myhost.com/api/option-chain-indices?symbol=ALL")
        .header("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36")
        .header("Accept-Encoding", "gzip, deflate, br")
        .retrieve()
        .bodyToMono(String.class)
        .subscribe(response -> {
            System.out.println("Received response: " + response);
        });

2. 强制设置超时时间 #

你的代码未配置超时，导致请求无限制挂起，必须添加连接超时和读取超时：

• HttpURLConnection设置超时：

connection1.setConnectTimeout(10000); // 10秒连接超时
connection1.setReadTimeout(30000); // 30秒读取超时

• WebClient全局配置超时：

@Bean
public WebClient webClient() {
    HttpClient httpClient = HttpClient.create()
            .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 10000)
            .responseTimeout(Duration.ofSeconds(30));

    return WebClient.builder()
            .clientConnector(new ReactorClientHttpConnector(httpClient))
            .build();
}

3. 检查代理配置 #

浏览器/PostMan可能配置了代理，而SpringBoot默认未使用代理导致无法访问目标服务。可以在代码中手动设置代理：

• HttpURLConnection设置代理：

Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("你的代理地址", 代理端口));
HttpURLConnection connection1 = (HttpURLConnection) url1.openConnection(proxy);

• WebClient设置代理：

HttpClient httpClient = HttpClient.create()
        .proxy(proxy -> proxy.type(ProxyProvider.Proxy.HTTP)
                .host("你的代理地址")
                .port(代理端口));

WebClient webClient = WebClient.builder()
        .clientConnector(new ReactorClientHttpConnector(httpClient))
        .build();

4. 排查SSL证书信任问题 #

目标服务的SSL证书可能未被JVM信任，导致连接卡住。可以：

• 将目标证书导入JVM信任库（生产环境推荐）；
• 临时禁用SSL验证（仅测试用，生产环境禁止）：

WebClient禁用SSL验证示例：

SslContext sslContext = SslContextBuilder.forClient()
        .trustManager(InsecureTrustManagerFactory.INSTANCE)
        .build();

HttpClient httpClient = HttpClient.create()
        .secure(t -> t.sslContext(sslContext));

WebClient webClient = WebClient.builder()
        .clientConnector(new ReactorClientHttpConnector(httpClient))
        .build();

5. 抓包对比请求差异 #

用Wireshark或tcpdump抓包，对比浏览器/PostMan和SpringBoot项目的请求：

• 确认请求是否成功发送到目标服务器；
• 检查服务端是否返回响应；
• 排查是否存在请求参数、头信息的差异。

也可以联系目标服务运维人员，查看服务器日志，确认请求是否被接收、处理时是否出现异常。

内容的提问来源于stack exchange，提问作者nSense