如何每隔5秒发送一次HttpPost

Question

在Java中，我希望每隔5秒发送一次HttpPost，而不等待响应。我该怎么做呢？

我使用以下代码：

HttpClient httpClient = new DefaultHttpClient();
HttpPost post = new HttpPost(url);
StringEntity params = new StringEntity(json.toString() + "\n");
post.addHeader("content-type", "application/json");
post.setEntity(params);
httpClient.execute(post);

Thread.sleep(5000);

httpClient.execute(post);

但它不起作用。

即使我失去了前一个连接，并建立了一个新的连接来发送第二个连接，第二个execute函数总是被阻塞。

Answer 1

你的问题留下了一堆问题，但它的基本点可以通过以下方式实现：

while(true){ //process executes infinitely. Replace with your own condition

  Thread.sleep(5000); // wait five seconds
  httpClient.execute(post); //execute your request

}

Answer 2

我尝试了你的代码，我得到了一个异常: java.lang.IllegalStateException:无效使用BasicClientConnManager:仍然分配的连接。确保在分配另一个连接之前释放该连接。

此异常已记录在HttpClient 4.0.1 - how to release connection?中

我可以通过使用以下代码的响应来释放连接：

public void sendMultipleRequests() throws ClientProtocolException, IOException, InterruptedException {
    HttpClient httpClient = new DefaultHttpClient();
    HttpPost post = new HttpPost("http://www.google.com");
    HttpResponse response = httpClient.execute(post);

    HttpEntity entity = response.getEntity();
    EntityUtils.consume(entity);

    Thread.sleep(5000);

    response = httpClient.execute(post);
    entity = response.getEntity();
    EntityUtils.consume(entity);
}

Answer 3

使用DefaultHttpClient是同步的，这意味着程序会被阻塞，等待响应。相反，您可以使用Maven库来执行异步请求(如果您不熟悉async-http-client，可以从search.maven.org下载jar文件)。示例代码可能如下所示：

import com.ning.http.client.*; //imports

try {
        AsyncHttpClient asyncHttpClient = new AsyncHttpClient();

        while(true) {

            asyncHttpClient
                    .preparePost("http://your.url/")
                    .addParameter("postVariableName", "postVariableValue")
                    .execute(); // just execute request and ignore response

            System.out.println("Request sent");

            Thread.sleep(5000);
        }
    } catch (Exception e) {
        System.out.println("oops..." + e);
    }