Getting Started with JAX-WS Web Service Clients

In this tutorial, you use the web service facilities provided by NetBeans IDE 6.0 to analyze a Spell Checker web service, after which you build a web client that interacts with it.

Contents

  Content on this page applies to the NetBeans 6.0 IDE

Software Needed for the Tutorial

Before you begin, you need to download or install the following software on your computer:

This is what your client will look like, with all data received from the web service:

Entry page

By the end of this tutorial, you discover that your only contribution to the application consists of providing the text to be checked, invoking an operation on the web service, and rendering the result. The IDE generates all the code needed for contacting the web service and sending the text. The spell checker web service takes care of the rest, it identifies the misspelled words and provides a list of suggested alternatives.

Note: The spell checker web service used in this tutorial is provided by the CDYNE Corporation. CDYNE develops, markets and supports a comprehensive suite of data enhancement, data quality and data analysis web services and business intelligence integration. The spell checker web service is one of the web services provided by CDYNE. Note that the strength of an application based on one or more web services depends on the availability and reliability of the web services. However, CDYNE's FAQ points out that it has a "100% availability objective" and that in the event of "natural disaster, act of terror, or other catastrophe, web service traffic is transferred to our secondary data center". NetBeans thanks CDYNE for enabling this tutorial to be written and for supporting its development.

Consuming the Spell Checker Web Service

To consume a web service, you need to create a web service client. For the creation of web service clients, NetBeans IDE 6.0 provides a client creation facility—the Web Service Client wizard that generates code for looking up a web service. It also provides facilities for developing the created web service client —a work area consisting of nodes in the Projects window. These facilities are part of the standard NetBeans IDE installation, they're available straight out of the box and no plug-ins are needed.

Creating the Client

In this section, we use a wizard to generate Java objects from the web service's WSDL file.

  1. Choose File > New Project (Ctrl-Shift-N). Under Categories, choose Web. Under Projects, choose Web Application. Click Next. Name the project SpellCheckService and make sure that you specify an appropriate server as your target server. (Refer to the "Getting Started" section for details.) Click Finish.
  2. In the Projects window, right-click the SpellCheckService project node and choose New > Other. In the New File wizard choose Web Services > Web Service Client. In the Web Service Client wizard, specify the URL to the web service:

    http://ws.cdyne.com/SpellChecker/check.asmx

    If you are behind a firewall, you might need to specify a proxy server—otherwise the WSDL file cannot be downloaded. If so, click Proxy Settings in the Web Service Client wizard and set your proxy host and port number.

  3. Enter org.netbeans.end2end.check.client as the package name. The package name specifies the package to which the client objects will be generated. You should now see this:

    Cdyne service

  4. Click Finish.

In the Projects window, within the Web Service References node, you should see the following:

Projects window

The Projects window shows that a web service called 'check' has made the operation 'CheckTextBody' available to your application. The 'CheckTextBody' operation checks a string for spelling errors and returns data to be processed by the client. You will use this operation throughout this tutorial.

In the Files window, within the build node, you should see the following:

Files window

The Files window shows the client stubs that were generated by the JAX-WS Web Service Client wizard.

Developing the Client

There are many ways to implement a web service client. The web service's WSDL file restricts the type of information that you can send to the web service, and it restricts the type of information you should expect to receive in return. However, the WSDL file lays no restrictions on how you pass the information it needs, nor on what the user interface consists of. The client implementation you build below consists of a JSP page which allows the user to enter text to be checked and a servlet which passes the text to the web service and then produces a report containing the result.

Coding the JSP Page

Our JSP page will simply consist of a text area, where the user will enter some text, and a button for sending the text to the web service.

  1. In the Projects window, expand the Web Pages node and double-click index.jsp so that it opens in the Source Editor.
  2. Copy the following code and paste it over the <body> tags in index.jsp:
    <body>
      <form name="Test" method="post" action="SpellCheckServlet">
         <p>Enter the text you want to check:</p>
         <p>
         <p><textarea rows="7" name="TextArea1" cols="40" ID="Textarea1"></textarea></p>
         <p>
         <input type="submit" value="Spell Check" name="spellcheckbutton">
      </form>
    </body>

    The above code specifies that when the submit button is clicked, the content of the textarea is posted to a servlet called SpellCheckServlet.

Creating and Coding the Servlet

In this section we create a servlet that will interact with the web service. However, as we will see, the code that performs the interaction will be provided by the IDE. As a result, you only need to deal with the business logic, that is, the preparation of the text to be sent and the processing of the result.

  1. Right-click the project node in the Projects window, choose New > Other and then choose Web > Servlet. Click Next. Name the servlet SpellCheckServlet and type org.netbeans.end2end.check.client in the Package drop-down. Click Next. Note that the URL mapping for this servlet is /SpellCheckServlet, as shown below:

    Display in browser

    Click Finish. The servlet opens in the Source Editor.

  2. Put your cursor inside the Source Editor, inside the processRequest method, add some new lines right at the top of the method.
  3. Right-click in the space that you created in the previous step, and choose Web Service Client Resources > Call Web Service Operation. Click the CheckTextBody operation in the "Select Operation to Invoke" dialog box,as shown below:

    Display in browser

    Click OK.

    Note: You can also drag and drop the operation node directly from the Projects window into the editor, instead of calling up the dialog shown above.

    At the top of the processRequest method you see a snippet of code that invokes the web service, as shown below:

    try { // Call Web Service Operation
        org.netbeans.end2end.check.client.CheckSoap port = service.getCheckSoap();
        // TODO initialize WS operation arguments here
        java.lang.String bodyText = "";
        java.lang.String licenseKey = "";
        // TODO process result here
        org.netbeans.end2end.check.client.DocumentSummary result = port.checkTextBody(bodyText, licenseKey);
        out.println("Result = "+result);
    } catch (Exception ex) {
        // TODO handle custom exceptions here
    }

    This method is all you need to work with to invoke the operation on the web service. In addition, the following lines of code are declared at the top of the class:

    @WebServiceRef(wsdlLocation = "http://ws.cdyne.com/SpellChecker/check.asmx?WSDL")
    private Check service;
  4. Replace the entire processRequest method with the code that follows. The in-line comments throughout the code below explain the purpose of each line.
    protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
    
        try {
    
            // Call Web Service Operation
            String TextArea1 = request.getParameter("TextArea1");
    
            org.netbeans.end2end.check.client.CheckSoap port = service.getCheckSoap();
    
            // TODO initialize WS operation arguments here
            java.lang.String bodyText = TextArea1;
            java.lang.String licenseKey = "0";
    
            // TODO process result here
            org.netbeans.end2end.check.client.DocumentSummary doc = port.checkTextBody(bodyText, licenseKey);
            String allcontent = doc.getBody();
    
            //From the retrieved document summary,
            //identify the number of wrongly spelled words:
            int no_of_mistakes = doc.getMisspelledWordCount();
    
            //From the retrieved document summary,
            //identify the array of wrongly spelled words:
            List allwrongwords = doc.getMisspelledWord();
    
            out.println("<html>");
            out.println("<head>");
    
            //Display the report's name as a title in the browser's titlebar:
            out.println("<title>Spell Checker Report</title>");
            out.println("</head>");
            out.println("<body>");
    
            //Display the report's name as a header within the body of the report:
            out.println("<h2><font color='red'>Spell Checker Report</font></h2>");
    
            //Display all the content (correct as well as incorrectly spelled) between quotation marks:
            out.println("<hr><b>Your text:</b> \"" + allcontent + "\"" + "<p>");
    
            //For every array of wrong words (one array per wrong word),
            //identify the wrong word, the number of suggestions, and
            //the array of suggestions. Then display the wrong word and the number of suggestions and
            //then, for the array of suggestions belonging to the current wrong word, display each
            //suggestion:
            for (int i = 0; i < allwrongwords.size(); i++) {
                String onewrongword = ((Words) allwrongwords.get(i)).getWord();
                int onewordsuggestioncount = ((Words) allwrongwords.get(i)).getSuggestionCount();
                List allsuggestions = ((Words) allwrongwords.get(i)).getSuggestions();
                out.println("<hr><p><b>Wrong word:</b><font color='red'> " + onewrongword + "</font>");
                out.println("<p><b>" + onewordsuggestioncount + " suggestions:</b><br>");
                for (int k = 0; k < allsuggestions.size(); k++) {
                    String onesuggestion = (String) allsuggestions.get(k);
                    out.println(onesuggestion);
                }
            }
    
            //Display a line after each array of wrong words:
            out.println("<hr>");
    
            //Summarize by providing the number of errors and display them:
            out.println("<font color='red'><b>Summary:</b> " + no_of_mistakes + " mistakes (");
            for (int i = 0; i < allwrongwords.size(); i++) {
                String onewrongword = ((Words) allwrongwords.get(i)).getWord();
                out.println(onewrongword);
            }
    
            out.println(").");
            out.println("</font>");
            out.println("</body>");
            out.println("</html>");
            out.close();
    
        } catch (Exception ex) {
            System.out.println("exception" + ex);
            out.println("exception" + ex);
        }
    
        out.println("</body>");
        out.println("</html>");
        out.close();
    }

    Note that error handling has not been dealt with in the code above. See Applying What You Have Learned for details.

Deploying the Client

The IDE uses an Ant build script to build and run your application. The IDE generates the build script based on the options you entered when creating the project. You can finetune these options in the project's Project Properties dialog box (right-click the project node in the Projects window and choose Properties).

  1. Right-click the project node and choose Run Project.

    After a while, the application should deploy and display the JSP page that you coded in the previous section. Enter some text, making sure that some of it is incorrectly spelled:

    Entry page

  2. Click Spell Check and see the result:

    Entry page


Applying What You Have Learned

Now that you have completed your first web service client in the IDE, it is time to stretch your skills and extend the application to be all that it was destined to be. Below are two suggested tasks to get you started.


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Next Steps

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