Revision 50
Added by Matt Jones about 24 years ago
| MetaCatServlet.java | ||
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import java.io.PrintWriter; |
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import java.io.IOException; |
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import java.io.Reader; |
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import java.io.StringReader; |
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import java.util.Enumeration; |
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import java.util.Hashtable; |
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import java.net.URL; |
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import java.net.MalformedURLException; |
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import java.sql.Connection; |
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import javax.servlet.ServletConfig; |
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import javax.servlet.ServletContext; |
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import javax.servlet.http.HttpServletResponse; |
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import javax.servlet.http.HttpUtils; |
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import oracle.xml.parser.v2.XSLStylesheet; |
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import oracle.xml.parser.v2.XSLException; |
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import oracle.xml.parser.v2.XMLDocumentFragment; |
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import oracle.xml.parser.v2.XSLProcessor; |
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/** |
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* A metadata catalog server implemented as a Java Servlet |
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* |
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* <p>Valid parameters are:<br> |
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* action=query -- query the values of all elements and attributes |
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* and return a result set of nodes<br> |
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* action=getdocument -- display an XML document in XML or HTML<br> |
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* qformat=xml -- display resultset from query in XML<br> |
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* qformat=html -- display resultset from query in HTML<br> |
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* action=getdocument -- display an XML document in XML or HTML<br> |
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* docid=34 -- display the document with the document ID number 34<br> |
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*/ |
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public class MetaCatServlet extends HttpServlet {
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|
| ... | ... | |
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private ServletContext context = null; |
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DBSimpleQuery queryobj = null; |
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DBReader docreader = null; |
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static String user = "jones"; |
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static String password = "your-pw-goes-here"; |
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static String defaultDB = "jdbc:oracle:thin:@localhost:1521:test"; |
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static String user = MetaCatUtil.user; |
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static String password = MetaCatUtil.password; |
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static String defaultDB = MetaCatUtil.defaultDB; |
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static String resultStyleURL = "file:///home/httpd/html/xmltodb/resultset.xsl"; |
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/** |
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* Initialize the servlet by creating appropriate database connections |
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*/ |
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public void init( ServletConfig config ) throws ServletException {
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try {
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super.init( config ); |
| ... | ... | |
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this.context = config.getServletContext(); |
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try {
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queryobj = new DBSimpleQuery(user, password, defaultDB); |
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docreader = new DBReader(user, password, defaultDB); |
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// Open a connection to the database |
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Connection dbconn = MetaCatUtil.openDBConnection( |
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"oracle.jdbc.driver.OracleDriver", |
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defaultDB, user, password); |
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queryobj = new DBSimpleQuery(dbconn); |
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docreader = new DBReader(dbconn); |
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} catch (Exception e) {
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} |
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} catch ( ServletException ex ) {
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| ... | ... | |
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} |
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} |
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/** Handle "GET" method requests from HTTP clients */ |
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public void doGet (HttpServletRequest request, HttpServletResponse response) |
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throws ServletException, IOException {
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|
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handleGetOrPost(response, params); |
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} |
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/** Handle "POST" method requests from HTTP clients */ |
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public void doPost( HttpServletRequest request, HttpServletResponse response) |
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throws ServletException, IOException {
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|
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} |
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/** |
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* routine to control servlet response depending on the action requested |
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* Valid "action" parameters are: |
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* query -- query the text values of all elements and attributes |
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* and return a result set of nodes |
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* getdocument -- display an XML document in XML or HTML given a document ID |
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* Control servlet response depending on the action parameter specified |
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*/ |
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private void handleGetOrPost(HttpServletResponse response, Hashtable params) |
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throws ServletException, IOException {
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handleQueryAction(out, params, response); |
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} else if (action.equals("getdocument")) {
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handleGetDocumentAction(out, params, response); |
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} else {
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out.println("Error: action not registered. Please report this error.");
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} |
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// Close the stream to the client |
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out.close(); |
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} |
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/** |
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* Handle the database query request and return a result set, possibly |
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* transformed from XML into HTML |
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*/ |
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private void handleQueryAction(PrintWriter out, Hashtable params, |
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HttpServletResponse response) {
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// Run the query |
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String query = ((String[])params.get("query"))[0];
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Hashtable nodelist = queryobj.findRootNodes(query); |
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// set content type and other response header fields first
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response.setContentType("text/xml");
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// Create a buffer to hold the xml result
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StringBuffer resultset = new StringBuffer();
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// Print the resulting root nodes |
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long nodeid; |
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out.println("<?xml version=\"1.0\"?>\n");
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out.println("<resultset>\n");
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out.println(" <query>" + query + "</query>");
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resultset.append("<?xml version=\"1.0\"?>\n");
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resultset.append("<resultset>\n");
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resultset.append(" <query>" + query + "</query>");
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Enumeration rootlist = nodelist.keys(); |
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while (rootlist.hasMoreElements()) {
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nodeid = ((Long)rootlist.nextElement()).longValue(); |
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out.println(" <nodeid>" + nodeid + "</nodeid>");
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resultset.append(" <nodeid>" + nodeid + "</nodeid>");
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} |
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out.println("</resultset>");
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resultset.append("</resultset>");
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String qformat = ((String[])params.get("qformat"))[0];
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if (qformat.equals("xml")) {
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// set content type and other response header fields first |
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response.setContentType("text/xml");
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out.println(resultset.toString()); |
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} else if (qformat.equals("html")) {
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// set content type and other response header fields first |
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response.setContentType("text/html");
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//out.println("Converting to HTML...");
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XMLDocumentFragment htmldoc = null; |
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try {
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XSLStylesheet style = new XSLStylesheet(new URL(resultStyleURL), null); |
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htmldoc = (new XSLProcessor()).processXSL(style, |
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(Reader)(new StringReader(resultset.toString())),null); |
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htmldoc.print(out); |
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} catch (Exception e) {
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out.println("Error transforming document:\n" + e.getMessage());
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} |
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} |
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} |
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/** |
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* Handle the database getdocument request and return a XML document, |
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* possibly transformed from XML into HTML |
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*/ |
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private void handleGetDocumentAction(PrintWriter out, Hashtable params, |
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HttpServletResponse response) {
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// Get the document indicated |
| ... | ... | |
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response.setContentType("text/xml");
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out.println(doc); |
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// Print the resulting root nodes |
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//out.println("<?xml version=\"1.0\"?>\n");
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//out.println("<docid>" + docid + "</docid>");
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} |
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} |
Also available in: Unified diff
changed database connection code, added utility class MetaCatUtil.java