Send a query to the server from my Java Class

Hi,

From my Java class(it is not a servlet), I want send a request like this to my server

POST /o/oauth2/token HTTP/1.1
Host: accounts.google.com
Content-Type: application/x-www-form-urlencoded

code=4/P7q7W91a-oMsCeLvIaQm6bTrgtp7&
client_id=8819981768.apps.googleusercontent.com&
client_secret={client_secret}&
redirect_uri=https://oauth2-login-demo.appspot.com/code&
grant_type=authorization_code

I want send it to the server in order to retrieve an answer.

Do I need set it in the request and send it, send it like a String?

I am very interested in make it work. Do you have any idea?

Many Thanks,

It is best to let the Java library handle the request headers, but the body of the request can just be a string. Here is an example:

void sendRequest()throws Exception {
    System.out.println("Start sending " + action + " request");
    URL url = new URL( serviceURL );
    HttpURLConnection rc = (HttpURLConnection)url.openConnection();
    //System.out.println("Connection opened " + rc );
    rc.setRequestMethod("POST");
    rc.setDoOutput( true );
    rc.setDoInput( true ); 
    rc.setRequestProperty( "Content-Type", "text/xml; charset=utf-8" );
    String reqStr = reqT.getRequest();  // the body of the request as a single String
    int len = reqStr.length();
    rc.setRequestProperty( "Content-Length", Integer.toString( len ) );
    rc.connect();    
    OutputStreamWriter out = new OutputStreamWriter( rc.getOutputStream() ); 
    out.write( reqStr, 0, len );
    out.flush();
    System.out.println("Request sent, reading response ");
    InputStreamReader read = new InputStreamReader( rc.getInputStream() );
     // note that Content-Length is available at this point
    StringBuilder sb = new StringBuilder();   
    int ch = read.read();
    while( ch != -1 ){
      sb.append((char)ch);
      ch = read.read();
    }
    response = sb.toString();
    read.close();
    rc.disconnect();
  }

There are also toolkits such as the Apache Software Foundation HttpClient.

Bill

Hi Bill,

many thanks for reply.

I have read the code and I have some doubts. For example:

What the variable action means? Is i the request?

Is serviceURL the formal URL without parameters something like www.angus.com

Could I use GET as method?

Why this code is needed:

while( ch != -1 )
{
sb.append((char)ch);
ch = read.read();

Also I have checked that "reqT" is not the request because it doesn't contain the method getRequest(), then what is it?
}

Regards,

I just cut and pasted this from old code so all variables may not apply to your situation

1. action is a parameter needed for this particular application

2. serviceURL is a complete URL, http://...etc etc

3. if you build a GET request it can not have a body. For a GET
you would have to build the parameters into the URL.

4. ch will only equal -1 when the complete response stream has been received

5. reqT is simply an object that can return the desired body - substitute whatever you want.

Bill