code: public HttpResponse execute(boolean isAsync) {
  		// 初始化URL
  		urlWithParamIfGet();
  		// 编码URL
  		if (this.encodeUrlParams) {
  			this.url = HttpUtil.encodeParams(this.url, this.charset);
  		}
  		// 初始化 connection
  		initConnecton();
  
  		// 发送请求
  		send();
  
  		// 手动实现重定向
  		HttpResponse httpResponse = sendRedirectIfPosible();
  
  		// 获取响应
  		if (null == httpResponse) {
  			httpResponse = new HttpResponse(this.httpConnection, this.charset, isAsync, isIgnoreResponseBody());
  		}
  		return httpResponse;
  	}
docs: 执行Reuqest请求
  
  @param isAsync 是否异步
  @return this