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POInserting XML data into MySQL database
 

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  1. POInserting XML data into MySQL database
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    <p>I am trying to insert XML data into a MySQL database. The SAX parser I wrote works on its own when tested. However, whenever I try to insert records into the database, I get a NullPointerException even though I made sure to assign values to workflow elements that were null. Here is my database Table code. package database;</p> <pre><code>//STEP 1. Import required packages import java.sql.*; import java.io.*; import org.w3c.dom.*; import javax.xml.parsers.*; public class Table { // JDBC driver name and database URL static final String JDBC_DRIVER = "com.mysql.jdbc.Driver"; static final String DB_URL = "jdbc:mysql://baldwin.isri.cmu.edu/SciSIP"; // Database credentials static final String USER = "user"; static final String PASS = "pass"; public Table() { } public void createTable() { Connection con = null; Statement stmt = null; try{ //STEP 2: Register JDBC driver Class.forName("com.mysql.jdbc.Driver"); //STEP 3: Open a connection System.out.println("Connecting to a selected database..."); con = DriverManager.getConnection(DB_URL, USER, PASS); System.out.println("Connected database successfully..."); //STEP 4: Execute a query System.out.println("Creating table in given database..."); stmt = con.createStatement(); String sql = "CREATE TABLE IF NOT EXISTS workflow" + "(id INTEGER not NULL AUTO_INCREMENT, " + " annotationBean VARCHAR(255), " + " date VARCHAR(255), " + " text VARCHAR(255), " + " identification VARCHAR(255), " + " PRIMARY KEY ( id ))"; stmt.executeUpdate(sql); System.out.println("Created table in given database..."); } catch(SQLException se) { //Handle errors for JDBC se.printStackTrace(); } catch(Exception e) { //Handle errors for Class.forName e.printStackTrace(); } finally { //finally block used to close resources try { if(stmt != null) con.close(); } catch(SQLException se) { }// do nothing try { if(con != null) con.close(); } catch(SQLException se) { se.printStackTrace(); }//end finally try }//end try System.out.println("Goodbye!"); } public void insertRecord(String annotationBean, String date, String text, String identification) { Connection con = null; Statement stmt = null; try { Class.forName("com.mysql.jdbc.Driver"); //Load the driver con = DriverManager.getConnection(DB_URL, USER, PASS); stmt = con.createStatement(); String sql = "INSERT INTO `workflow` VALUES ('"+annotationBean+"', '"+date+"', '"+text+"', '"+identification+"')"; stmt.execute(sql); //Insert a row System.out.println("Record Inserted into Database..."); } catch(SQLException se) { //Handle errors for JDBC se.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } finally { //finally block used to close resources try { if(stmt != null) con.close(); } catch(SQLException se) { }// do nothing try { if(con != null) con.close(); } catch(SQLException se) { se.printStackTrace(); }//end finally try }//end try } </code></pre> <p>Here is my parser code with the insert record statement.</p> <pre><code>package parser; import java.io.IOException; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import javax.xml.parsers.ParserConfigurationException; import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import org.xml.sax.Attributes; import org.xml.sax.SAXException; import org.xml.sax.helpers.DefaultHandler; import database.Table; public class XML_Parser_SAX extends DefaultHandler{ List aWorkflow; private String tempVal; //to maintain context private Workflow tempWorkflow; public XML_Parser_SAX(){ aWorkflow = new ArrayList(); } public void runExample() { parseDocument(); printData(); } private void parseDocument() { //get a factory SAXParserFactory spf = SAXParserFactory.newInstance(); try { //get a new instance of parser SAXParser sp = spf.newSAXParser(); //parse the file and also register this class for call backs sp.parse("workflow.xml", this); }catch(SAXException se) { se.printStackTrace(); }catch(ParserConfigurationException pce) { pce.printStackTrace(); }catch (IOException ie) { ie.printStackTrace(); } } /** * Iterate through the list and print * the contents */ private void printData(){ System.out.println("Number of Tasks in Workflow: '" + aWorkflow.size() + "'."); Iterator it = aWorkflow.iterator(); while(it.hasNext()) { System.out.println(it.next().toString()); } } //Event Handlers public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { //reset tempVal = ""; if(qName.equalsIgnoreCase("annotationBean")) { //create a new instance of employee tempWorkflow = new Workflow(); tempWorkflow.setAnnotationBean(attributes.getValue("class")); System.out.println("class"); } } public void characters(char[] ch, int start, int length) throws SAXException { tempVal = new String(ch,start,length); } public void endElement(String uri, String localName, String qName) throws SAXException { if(qName.equalsIgnoreCase("annotationBean")) { //add it to the list aWorkflow.add(tempWorkflow); System.out.println("annotationBean"); } else if (qName.equalsIgnoreCase("date")) { if (tempVal != null) { tempWorkflow.setDate(tempVal); } else { tempWorkflow.setDate("null"); } System.out.println(tempWorkflow.getDate()); } else if (qName.equalsIgnoreCase("text")) { if (tempVal != null) { tempWorkflow.setText(tempVal); } else { tempWorkflow.setText("null"); } System.out.println(tempWorkflow.getText()); } else if (qName.equalsIgnoreCase("identification")) { if (tempVal != null) { tempWorkflow.setIdentification(tempVal); } else { tempWorkflow.setIdentification("null"); } System.out.println(tempWorkflow.getIdentification()); } Table t = new Table(); //t.createTable(); t.insertRecord(tempWorkflow.getAnnotationBean(), tempWorkflow.getDate(), tempWorkflow.getText(), tempWorkflow.getIdentification()); } public static void main(String[] args){ XML_Parser_SAX parse = new XML_Parser_SAX(); parse.runExample(); } } </code></pre> <p>Can someone please tell me why this is giving me the NullPointerException? Thanks in advance!!!</p> <p>Here is the stacktrace:</p> <pre><code>Exception in thread "main" java.lang.NullPointerException at parser.XML_Parser_SAX.endElement(XML_Parser_SAX.java:126) at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:606) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1741) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2898) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:488) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764) at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123) at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210) at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568) at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:302) at javax.xml.parsers.SAXParser.parse(SAXParser.java:274) at parser.XML_Parser_SAX.parseDocument(XML_Parser_SAX.java:49) at parser.XML_Parser_SAX.runExample(XML_Parser_SAX.java:35) at parser.XML_Parser_SAX.main(XML_Parser_SAX.java:131) </code></pre> <p>Yes, workflow.xml exists. Here is a copy of it below.</p> <pre><code>&lt;workflow xmlns="http://taverna.sf.net/2008/xml/t2flow" version="1" producedBy="taverna- 2.4.0"&gt;&lt;dataflow id="8781d5f4-d0ba-48a8-a1d1-14281bd8a917" role="top"&gt;&lt;name&gt;Hello_World&lt;/name&gt; &lt;inputPorts /&gt;&lt;outputPorts&gt;&lt;port&gt;&lt;name&gt;greeting&lt;/name&gt;&lt;annotations /&gt;&lt;/port&gt;&lt;/outputPorts&gt; &lt;processors&gt;&lt;processor&gt;&lt;name&gt;hello&lt;/name&gt;&lt;inputPorts /&gt;&lt;outputPorts&gt;&lt;port&gt;&lt;name&gt;value&lt;/name&gt; &lt;depth&gt;0&lt;/depth&gt;&lt;granularDepth&gt;0&lt;/granularDepth&gt;&lt;/port&gt;&lt;/outputPorts&gt;&lt;annotations /&gt; &lt;activities&gt;&lt;activity&gt;&lt;raven&gt;&lt;group&gt;net.sf.taverna.t2.activities&lt;/group&gt; &lt;artifact&gt;stringconstant-activity&lt;/artifact&gt;&lt;version&gt;1.4&lt;/version&gt;&lt;/raven&gt; &lt;class&gt;net.sf.taverna.t2.activities.stringconstant.StringConstantActivity&lt;/class&gt;&lt;inputMap /&gt; &lt;outputMap&gt;&lt;map from="value" to="value" /&gt;&lt;/outputMap&gt;&lt;configBean encoding="xstream"&gt; &lt;net.sf.taverna.t2.activities.stringconstant.StringConstantConfigurationBean xmlns=""&gt; &lt;value&gt;Hello, World!&lt;/value&gt; &lt;/net.sf.taverna.t2.activities.stringconstant.StringConstantConfigurationBean&gt;&lt;/configBean&gt; &lt;annotations /&gt;&lt;/activity&gt;&lt;/activities&gt;&lt;dispatchStack&gt;&lt;dispatchLayer&gt;&lt;raven&gt; &lt;group&gt;net.sf.taverna.t2.core&lt;/group&gt;&lt;artifact&gt;workflowmodel-impl&lt;/artifact&gt; &lt;version&gt;1.4&lt;/version&gt;&lt;/raven&gt; &lt;class&gt;net.sf.taverna.t2.workflowmodel.processor.dispatch.layers.Parallelize&lt;/class&gt; &lt;configBean encoding="xstream"&gt; &lt;net.sf.taverna.t2.workflowmodel.processor.dispatch.layers.ParallelizeConfig xmlns=""&gt; &lt;maxJobs&gt;1&lt;/maxJobs&gt; &lt;/net.sf.taverna.t2.workflowmodel.processor.dispatch.layers.ParallelizeConfig&gt; &lt;/configBean&gt;&lt;/dispatchLayer&gt;&lt;dispatchLayer&gt;&lt;raven&gt;&lt;group&gt;net.sf.taverna.t2.core&lt;/group&gt; &lt;artifact&gt;workflowmodel-impl&lt;/artifact&gt;&lt;version&gt;1.4&lt;/version&gt;&lt;/raven&gt; &lt;class&gt;net.sf.taverna.t2.workflowmodel.processor.dispatch.layers.ErrorBounce&lt;/class&gt; &lt;configBean encoding="xstream"&gt;&lt;null xmlns="" /&gt;&lt;/configBean&gt;&lt;/dispatchLayer&gt;&lt;dispatchLayer&gt; &lt;raven&gt;&lt;group&gt;net.sf.taverna.t2.core&lt;/group&gt;&lt;artifact&gt;workflowmodel-impl&lt;/artifact&gt; &lt;version&gt;1.4&lt;/version&gt;&lt;/raven&gt; &lt;class&gt;net.sf.taverna.t2.workflowmodel.processor.dispatch.layers.Failover&lt;/class&gt;&lt;configBean encoding="xstream"&gt;&lt;null xmlns="" /&gt;&lt;/configBean&gt;&lt;/dispatchLayer&gt;&lt;dispatchLayer&gt;&lt;raven&gt; &lt;group&gt;net.sf.taverna.t2.core&lt;/group&gt;&lt;artifact&gt;workflowmodel-impl&lt;/artifact&gt; &lt;version&gt;1.4&lt;/version&gt;&lt;/raven&gt; &lt;class&gt;net.sf.taverna.t2.workflowmodel.processor.dispatch.layers.Retry&lt;/class&gt;&lt;configBean encoding="xstream"&gt;&lt;net.sf.taverna.t2.workflowmodel.processor.dispatch.layers.RetryConfig xmlns=""&gt; &lt;backoffFactor&gt;1.0&lt;/backoffFactor&gt; &lt;initialDelay&gt;1000&lt;/initialDelay&gt; &lt;maxDelay&gt;5000&lt;/maxDelay&gt; &lt;maxRetries&gt;0&lt;/maxRetries&gt; &lt;/net.sf.taverna.t2.workflowmodel.processor.dispatch.layers.RetryConfig&gt;&lt;/configBean&gt; &lt;/dispatchLayer&gt;&lt;dispatchLayer&gt;&lt;raven&gt;&lt;group&gt;net.sf.taverna.t2.core&lt;/group&gt; &lt;artifact&gt;workflowmodel-impl&lt;/artifact&gt;&lt;version&gt;1.4&lt;/version&gt;&lt;/raven&gt; &lt;class&gt;net.sf.taverna.t2.workflowmodel.processor.dispatch.layers.Invoke&lt;/class&gt;&lt;configBean encoding="xstream"&gt;&lt;null xmlns="" /&gt;&lt;/configBean&gt;&lt;/dispatchLayer&gt;&lt;/dispatchStack&gt; &lt;iterationStrategyStack&gt;&lt;iteration&gt;&lt;strategy /&gt;&lt;/iteration&gt;&lt;/iterationStrategyStack&gt; &lt;/processor&gt;&lt;/processors&gt;&lt;conditions /&gt;&lt;datalinks&gt;&lt;datalink&gt;&lt;sink type="dataflow"&gt; &lt;port&gt;greeting&lt;/port&gt;&lt;/sink&gt;&lt;source type="processor"&gt;&lt;processor&gt;hello&lt;/processor&gt; &lt;port&gt;value&lt;/port&gt;&lt;/source&gt;&lt;/datalink&gt;&lt;/datalinks&gt;&lt;annotations&gt;&lt;annotation_chain encoding="xstream"&gt;&lt;net.sf.taverna.t2.annotation.AnnotationChainImpl xmlns=""&gt; &lt;annotationAssertions&gt; &lt;net.sf.taverna.t2.annotation.AnnotationAssertionImpl&gt; &lt;annotationBean class="net.sf.taverna.t2.annotation.annotationbeans.Author"&gt; &lt;text&gt;Stian Soiland-Reyes&lt;/text&gt; &lt;/annotationBean&gt; &lt;date&gt;2012-01-03 15:10:48.73 GMT&lt;/date&gt; &lt;creators /&gt; &lt;curationEventList /&gt; &lt;/net.sf.taverna.t2.annotation.AnnotationAssertionImpl&gt; &lt;/annotationAssertions&gt; &lt;/net.sf.taverna.t2.annotation.AnnotationChainImpl&gt;&lt;/annotation_chain&gt;&lt;annotation_chain encoding="xstream"&gt;&lt;net.sf.taverna.t2.annotation.AnnotationChainImpl xmlns=""&gt; &lt;annotationAssertions&gt; &lt;net.sf.taverna.t2.annotation.AnnotationAssertionImpl&gt; &lt;annotationBean class="net.sf.taverna.t2.annotation.annotationbeans.DescriptiveTitle"&gt; &lt;text&gt;Hello World&lt;/text&gt; &lt;/annotationBean&gt; &lt;date&gt;2012-01-03 15:10:54.167 GMT&lt;/date&gt; &lt;creators /&gt; &lt;curationEventList /&gt; &lt;/net.sf.taverna.t2.annotation.AnnotationAssertionImpl&gt; &lt;/annotationAssertions&gt; &lt;/net.sf.taverna.t2.annotation.AnnotationChainImpl&gt;&lt;/annotation_chain&gt; &lt;annotation_chain_2_2 encoding="xstream"&gt;&lt;net.sf.taverna.t2.annotation.AnnotationChainImpl xmlns=""&gt; &lt;annotationAssertions&gt; &lt;net.sf.taverna.t2.annotation.AnnotationAssertionImpl&gt; &lt;annotationBean class="net.sf.taverna.t2.annotation.annotationbeans.IdentificationAssertion"&gt; &lt;identification&gt;8781d5f4-d0ba-48a8-a1d1-14281bd8a917&lt;/identification&gt; &lt;/annotationBean&gt; &lt;date&gt;2012-01-03 15:12:21.684 GMT&lt;/date&gt; &lt;creators /&gt; &lt;curationEventList /&gt; &lt;/net.sf.taverna.t2.annotation.AnnotationAssertionImpl&gt; </code></pre> <p> </p> <pre><code>&lt;text&gt;One of the simplest workflows possible. No workflow input ports, a single workflow output port "greeting", outputting "Hello, world!" as produced by the String Constant "hello".&lt;/text&gt; &lt;/annotationBean&gt; &lt;date&gt;2012-01-03 15:12:15.643 GMT&lt;/date&gt; &lt;creators /&gt; &lt;curationEventList /&gt; &lt;/net.sf.taverna.t2.annotation.AnnotationAssertionImpl&gt; &lt;/annotationAssertions&gt; &lt;/net.sf.taverna.t2.annotation.AnnotationChainImpl&gt;&lt;/annotation_chain&gt;&lt;/annotations &gt; &lt;/dataflow&gt;&lt;/workflow&gt; </code></pre>
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