import org.apache.http.protocol.RequestContentHC4; //导入依赖的package包/类
public MinimalClientExec(
        final HttpRequestExecutor requestExecutor,
        final HttpClientConnectionManager connManager,
        final ConnectionReuseStrategy reuseStrategy,
        final ConnectionKeepAliveStrategy keepAliveStrategy) {
    Args.notNull(requestExecutor, "HTTP request executor");
    Args.notNull(connManager, "Client connection manager");
    Args.notNull(reuseStrategy, "Connection reuse strategy");
    Args.notNull(keepAliveStrategy, "Connection keep alive strategy");
    this.httpProcessor = new ImmutableHttpProcessor(
            new RequestContentHC4(),
            new RequestTargetHostHC4(),
            new RequestClientConnControl(),
            new RequestUserAgentHC4(VersionInfoHC4.getUserAgent(
                    "Apache-HttpClient", "org.apache.http.client", getClass())));
    this.requestExecutor    = requestExecutor;
    this.connManager        = connManager;
    this.reuseStrategy      = reuseStrategy;
    this.keepAliveStrategy  = keepAliveStrategy;
}