从HttpClient4迁移至HttpClient5：无法使用setSSLContext方法

升级Apache HttpClient从4.x到5.x后，原代码中HttpClientBuilder.setSSLContext()方法被移除，报错：

The method setSSLContext(sslcontext) is undefined for the type HttpClientBuilder

原代码：

import org.apache.hc.client5.http.classic.HttpClient;
import org.apache.hc.client5.http.impl.classic.HttpClientBuilder;

SSLContext sslcontext = SSLContext.getDefault();
HttpClient httpclient = HttpClientBuilder.create().setSSLContext(sslcontext).build();
ClientHttpRequestFactory reqFac = new HttpComponentsClientHttpRequestFactory(httpclient);

替代实现方案 #

在HttpClient 5.x中，需通过SSLConfig类封装SSLContext配置，再传递给HttpClientBuilder：

import org.apache.hc.client5.http.classic.HttpClient;
import org.apache.hc.client5.http.impl.classic.HttpClientBuilder;
import org.apache.hc.client5.http.config.SSLConfig;

// 获取默认SSLContext
SSLContext sslcontext = SSLContext.getDefault();

// 构建SSLConfig并绑定SSLContext
SSLConfig sslConfig = SSLConfig.custom()
        .setSslContext(sslcontext)
        .build();

// 创建HttpClient时传入配置好的SSLConfig
HttpClient httpclient = HttpClientBuilder.create()
        .setSSLConfig(sslConfig)
        .build();

ClientHttpRequestFactory reqFac = new HttpComponentsClientHttpRequestFactory(httpclient);

扩展配置（可选） #

如果需要自定义SSL协议、主机名验证规则等，可在SSLConfig.custom()中追加配置项：

SSLConfig sslConfig = SSLConfig.custom()
        .setSslContext(sslcontext)
        .setProtocols(new String[]{"TLSv1.2", "TLSv1.3"}) // 指定允许的SSL协议版本
        .setHostnameVerifier(NoopHostnameVerifier.INSTANCE) // 关闭主机名验证（仅建议测试环境使用）
        .build();

内容的提问来源于stack exchange，提问作者Ravi