看HttpClient的源代碼可以發現URI是個線索，在execute方法中會判斷URI中設置的是否是絕對路徑還是相對路徑，如果是相對路徑時httpclient會將defaulthost+uri拼接為完整的請求地址。如果URI中設置了scheme并且URI配置了host就會用URI完整的絕對路徑作為請求地址。判斷邏輯如下

public final HttPResponse execute(HttpUriRequest request,                                  HttpContext context)    throws IOException, ClientProtocolException {    if (request == null) {        throw new IllegalArgumentException            ("Request must not be null.");    }    return execute(determineTarget(request), request, context);}private static HttpHost determineTarget(HttpUriRequest request) throws ClientProtocolException {    // A null target may be acceptable if there is a default target.    // Otherwise, the null target is detected in the director.    HttpHost target = null;    URI requestURI = request.getURI();    if (requestURI.isAbsolute()) {        target = URIUtils.extractHost(requestURI);        if (target == null) {            throw new ClientProtocolException(                    "URI does not specify a valid host name: " + requestURI);        }    }    return target;}分析完就找到了方法解決問題了，在請求時設置URI即可，要注意的是build URI的時候要配置scheme參數才能生效。