processquery.java

使用模式映射方法

/*
 * ProcessQuery.java
 *
 * Created on 2007年5月10日, 下午11:12
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

package XRSystem.Process;

/**
 *
 * @author 王刚
 */

import com.fatdog.xmlEngine.ResultList;
import com.fatdog.xmlEngine.XQEngine;
import com.fatdog.xmlEngine.exceptions.*;
import javax.xml.parsers.*;

import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;

import java.lang.*;
import java.util.*;
import java.sql.*;

import XRSystem.DataAccess.*;
public class ProcessQuery {
    
    private String DocumentName;
    private String DocURL;
    private String XPathExpr;
    private XQEngine ThisEngine;
    private boolean PRETTYPRINT = true;
    private String RunResult;
    
    /** Creates a new instance of ProcessQuery */
    public ProcessQuery(String DocumentName,String XPathExpr) {
        this.DocumentName = DocumentName;
        this.XPathExpr = XPathExpr;
    }
    
    private String GetDocURL() {
        
        ResultSet rs = null;
        String SQLString = "SELECT DocumentPath FROM Document WHERE DocumentName ="+"'"+DocumentName+"'";
        try{
            rs = new SQLResultSet().ExecuteSQL(SQLString);
            while(rs.next()){
                DocURL = rs.getString(1);
            }
        } catch(SQLException e){e.printStackTrace();} catch(Exception e){e.printStackTrace();}
        return DocURL;
    }
    
    public String RunQuery() {
        ThisEngine = new XQEngine();
        try{
            installSunXMLReader();
            ThisEngine.setDocument(this.GetDocURL());
            ResultList results = ThisEngine.setQuery(XPathExpr);
            RunResult = results.emitXml(PRETTYPRINT) + "\n";
        }catch( Exception e ){e.printStackTrace();}
        return RunResult;        
    }
    
    private void installXercesXMLReader() throws Exception {
        String parserName = "org.apache.xerces.parsers.SAXParser";
        XMLReader parser = XMLReaderFactory.createXMLReader( parserName );
        
        ThisEngine.setXMLReader( parser );
    }
    
    private void installSunXMLReader() throws Exception {
        SAXParserFactory spf = SAXParserFactory.newInstance();
        try {
            SAXParser parser = spf.newSAXParser();
            XMLReader reader = parser.getXMLReader();
            
            ThisEngine.setXMLReader( reader );
        } catch( Exception e )    { throw e; }
    }
    

    
    public static void main(String[] args)
    {
        System.out.println(new ProcessQuery("pub.xml","//author").RunQuery());
    }

}