要回答我自己的问题:要释放连接(以及与请求关联的任何其他资源)，您必须关闭 HttpEntity 返回的 InputStream:

To answer my own question: to release the connection (and any other resources associated with the request) you must close the InputStream returned by the HttpEntity:

InputStream is = entity.getContent();

.... process the input stream ....

is.close();       // releases all resources

来自 文档