Accessing Yahoo Search Web Service using JAXB and JSP

In this blog, I will explain steps required to access search web service of Yahoo using a JSP. Yahoo provides a service that can be accessed using simple URL. It needs application id, which can be obtained if you like. But in this example, I am using demo application id called YahooDemo.

For example, the following URL can be used to search for srikanthpragada.

http://search.yahooapis.com/WebSearchService/V1/webSearch?appid=YahooDemo&query=srikanthpragada

It returns results in the form of XML. The schema used for XML document is provided at the URL.

http://api.search.yahoo.com/WebSearchService/V1/WebSearchResponse.xsd

In case you want to use XPATH to search for results in XML document instead of using Java classes using JAXB, please my blog regarding using Yahoo Search service at http://www.srikanthtechnologies.com/blog/yahoosearch.html

For more information about Yahoo Search Service, refer to Yahoo Search Service

Creating Java clases from XML schema using JAXB

The main theme of this example is to show how to use JAXB (Java Architecture For XML Binding). JAXB converts XML schema to Java classes. We use NetBeans 6.1 to create Java classes through JAXB by taking URL for schema.

Create a new web project using File->New Project. Select web category and web application in projects.
Give yahoosearchclient as the name of the project. Specify other details like location and server as you like. It doesn't need any framework so select no framework.
NetBeans creates a new project with index.jsp as the only page.
Select File ->New File. Select XML in category and JAXB binidng under File Types.
Enter Binding name as YahooSearchResult and URL in Select From URL textbox as shown below.
JAXB creates necessary classes depending on the scheam. In this example, it creates ResultSet and ResultType classes. You can examine these classe using Files window (Window->Files) for this project. These classes appear under Build->Generated. Now compile project to compile the classes generated by JAXB.

Creating JSP to call Yahoo Search Service

The following steps use classes created by JAXB to receive the XML data sent by Yahoo Search Service and display data as hyperlinks to user.

Modify index.jsp as follows to use yahoo search service and display the results. It unmarshalls the XML document provide by Yahoo Service and creates objects of classes generated by JAXB.

<%@page contentType="text/html" pageEncoding="UTF-8" import="java.io.*,java.net.*,javax.xml.*,javax.xml.bind.*,yahoo.srch.*,java.util.List" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Yahoo Search Client</title>
    </head>
    <body>
        <h2>Yahoo Search Client</h2>
        <form action="index.jsp">
            Enter your search string  : <input type=text name="word" size=20 value="${param.word}"> 
            <input type=submit value="Search" />
        </form>
        
        <p/>
        
        <%
        String word =  request.getParameter("word");
        if ( word == null) return;
        
        // create JAXB unmarshaller with no schema validation. 
        JAXBContext context = JAXBContext.newInstance(ResultSet.class);
        Unmarshaller unmarshaller = context.createUnmarshaller();
        unmarshaller.setSchema(null);   //No Schema
            
        // search for the given string
        String yahoourl = "http://search.yahooapis.com/WebSearchService/V1/webSearch?appid=YahooDemo&query=" + word;
        URL url = new URL(yahoourl);
     
        // unmarshall XML document provided by service. 
        ResultSet  allresults = ResultSet.class.cast(unmarshaller.unmarshal(url.openStream()));
        List<ResultType> results = allresults.getResult();

        // display results as hyperlinks
        for(ResultType res : results) {
            out.println("<a href=" + res.getUrl() + ">" +  res.getTitle() + "</a><p/>");
        }
        %>
        
    </body>
</html>

Run index.jsp and enter word to search for. You must see results returned by Yahoo Search Service.
You can follow more or less the same process to call many other useful web services provided by Yahoo.

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Keep Learning.

Srikanth.