我可以使用相同的 HttpURLConnection 多次发送相同的 HTTP 请求吗？

Question

In order to send a string data to the server once, I do as below:

1. Make “HttpURLConnection” to my URL address and open it

2. Set the required headers

3. for the connection I Set setDoOutput to True

4. new a DataOutputStream from my connection and finally write my string data to it.

    HttpURLConnection myConn = (HttpURLConnection); myUrl.openConnection(); myConn.setRequestProperty("Accept", "application/json, text/plain, */*"); myConn.setDoOutput(true); DataOutputStream my_output = new DataOutputStream(myConn.getOutputStream()); my_output.write(myData.getBytes("UTF-8"));

But what to do if I want to send exactly the same data with same URl and headers multiple times? Can I write to it multiple times?(I mean that is it possible to use the last line of code multiple times?) Or should I repeat the above steps and try it with a new connection? And if yes should I wait for some second or millisecond before sending the next one? I also searched for some other alternatives such as “HttpClient” Http API and making synchronous Http request which as far as I got can help me setting the headers only once. At the end, I appreciate your help and support and any other alternatives would be welcome. Thanks a million.

Answer 1

I understand that the question has be answered in the comments, but I am leaving this here so that future viewers can see it.

An HTTP request contains 3 main parts:

• Request Line: Method, Path, Protocol
• Headers: Key-Pairs
• Body: Data

Running my_output.write() will just add bytes to the body until my_output.flush() has been executed. Flushing the stream will write the data to the server.

Because HTTP requests are usually closed by the server once all data has been sent/received, whether or not you create a new connection or just add on to the body depends on your intentions . Typically, clients will create a new connection for each request because each response should be handled individually, rather than sending a repetitive body. This will vary though because some servers choose to hold a connection (such as WebSockets).

Answer 2

thanks to paulsm4 and null who gave me a better insight toward http connection persistence and life cycle,? but about the second part of my question, any other alternative to send the request to the server with the same 3 main parts. since making new connections and setting headers take times which decrease my performance at this part of code? I want to send them as fast as possible. would using asynchronous http request helpful at this predicament? Thanks all.

Answer 3

If you are open to external libraries, you may find this chart insightful:

AsyncHttpClient would be a good fit for your intentions.

Alternatively, you can use cURL by running a terminal command with Runtime.getRuntime().exec() . More information about using cURL with POST Requests can be found here . While cURL is efficient, you have to depend on the fact that your OS supports the command (though usually all devices that can run Java have this command).