java.net.HttpURLConnection Check / TEST Connection while only POST Method is available

问题

There is a webservice on some other server which I am calling in my Java Code. It responses only for POST method (there is NO GET method) available. This request / response works correctly while I implement the full method with request XML and call the Webservice, i.e. it works correctly.

But requirement is --> there will be three webservice URLs (configurable from my Application by Admin User). First, I have to check whether the first URL one is connection or not. If Not connecting, then go for second connection...then 3rd one.

I am using the below code , but again and again it is giving me

{responseCode = 500}. and not {responseCode = 200}.

Kindly Suggest me how can I check the connection is established or not ?

/* Start : Surajit Biswas (25-NOV-2015) : test if Alcatel WS is connection or not*/
    String wsURL = "https://hostservername:postnumber";
            String wsUserName = "someUserName";
            String wsPassword = "somePassword";
            String requestXML = "<soapenv:Envelope ...."; /* As I told, not required here*/  
            try{
                String authString = wsUserName+":"+wsPassword;
                byte[] byteAuthStr = authString.getBytes();
                String authBase64Str = Base64.encode(byteAuthStr);
                System.out.println(authBase64Str);
            URL url = new URL(wsURL);
            URLConnection  conn =  url.openConnection();
            HttpURLConnection connection = (HttpURLConnection)conn;
            connection.setDoOutput(true); 
            /*connection.setRequestMethod("GET");
             connection.setRequestMethod("POST");*/     connection.setRequestProperty("Content-Type", "text/xml; charset=utf-8");
            connection.setRequestProperty("Authorization", "Basic "+authBase64Str);
            connection.connect();
           System.out.println( connection.getResponseCode());
           boolean connected = false;
           switch (connection.getResponseCode()) {
           case HttpURLConnection.HTTP_OK:
               System.out.println(url + " **OK**");
               connected = true;
               break; // fine, go on
           case HttpURLConnection.HTTP_GATEWAY_TIMEOUT:
               System.out.println(url + " **gateway timeout**");
               break;// retry
           case HttpURLConnection.HTTP_UNAVAILABLE:
               System.out.println(url + "**unavailable**");
               break;// retry, server is unstable
           default:
               System.out.println(url + " **unknown response code**.");
               break ; // abort
       }
    }catch(Exception ex){
                System.err.println("Error creating HTTP connection");
                System.out.println(ex.getMessage());
            }
        }
/* End : Surajit Biswas (25-NOV-2015) : test if Alcatel WS is connection or not*/

Thanks in advance for your help... Surajit Biswas

回答1:

The way to implement your requirement is simply to try to post to each URL in turn and stop as soon as you get a success.

What you're attempting here is tantamount to trying to predict the future. It won't work. It can't work.

回答2:

You can check with this line

URLConnection  conn =  url.openConnection();
if(conn != null)
{
  //do your stuff
}
else //call other url

来源：https://stackoverflow.com/questions/33910154/java-net-httpurlconnection-check-test-connection-while-only-post-method-is-ava

标签

java

java-ee

httpurlconnection