Research Log of Web Science Students

Computer Science is not simply programming

My first dip at Web Services

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Yesterday I found myself delving into my first foray into the whole new world of web services when I was helping Kee(a .NET person) connect to DivShare for the upload feature in their web app using Java.

I have thought about making my own framework in Java for URL rewriting because I knew I would need it someday to make API calls but what I didn’t know was a class like this already exists in the Java SDK.

To call a web service first determine:

1. The url where the web service will get requests
2. The parameters the web service requires

From there, it’s a matter of making a post request by forming the parameters that the web service needs.

To form the parameters for call to a web service means forming a URL (given by the web service) with the parameters right after. Ever noticed how some URLs can be so long?


The parameters are written into the url by attribute value pairs as in the picture above:


To do this in Java, use URLEncoder’s encode method:

String data = URLEncoder.encode("service", "UTF-8") 
            + "=" + URLEncoder.encode("ah", "UTF-8");

data += "&" + URLEncoder.encode("continue", "UTF-8") + 
        "=" + URLEncoder.encode("", "UTF-8");

Making a post request is done like this:

 URL url = new URL("http://hostname:80/cgi");
 URLConnection conn = url.openConnection();
 OutputStreamWriter wr = 
         new OutputStreamWriter(conn.getOutputStream());
 // Get the response
BufferedReader rd = new BufferedReader(new

String line;
while ((line = rd.readLine()) != null) {
    // Process line...

Some more tutorials I found here


Written by Jose Asuncion

October 2, 2009 at 4:48 am

Posted in Hardwire

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