xmlparserutil.java

简单的web应用,实现基本的购物车功能,有良好的扩展性

package myjdbc.util;

import java.io.File;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXParseException;
import org.xml.sax.SAXException;
import java.io.IOException;
import org.w3c.dom.NodeList;
import org.w3c.dom.Element;

public class XMLParserUtil {
  private Document document;
  public XMLParserUtil(String configFile) throws ParserConfigurationException,SAXException,IOException{
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    //告诉工厂将所需解析器类型
    dbf.setValidating(false);
    //使用工厂获取JAXP 解析器对象
    DocumentBuilder parser = dbf.newDocumentBuilder();
    // 告诉解析器如何处理错误，注意在JAXP API 中
    // DOM 解析器依赖SAX API处理错误
    parser.setErrorHandler(new ErrorHandler(){
      public void warning(SAXParseException e) {
        System.err.println("WARNING: "+e.getMessage());
      }

      public void error(SAXParseException e) {
        System.err.println("ERROR: " + e.getMessage());
      }

      public void fatalError(SAXParseException e) throws SAXException {
        System.err.println("FATAL: " + e.getMessage());
        throw e; // 重新抛出错误
      }
    }
    );
    // 最后使用JAXP 解析器解析文件。此调用返回
    // 一个Document 对象，有了这个对象，类的
    // 其余部分使用DOM API处理它，不再需要JAXP
    document = parser.parse(configFile);
  }
  public Object[] getFieldAndColumnMapping(String _tableName) throws Exception{
    String[] columns = null;
    String[] classFileds = null;
    Element root = (Element)document.getElementsByTagName("table-config").item(0);
    Element subroot = (Element)root.getElementsByTagName("class").item(0);
    //subroot元素的name属性的属性值
    String className = subroot.getAttribute("name");
    //subroot元素的table属性的属性值
    String tableName = subroot.getAttribute("table");
    if (! _tableName.equalsIgnoreCase(tableName))
      throw new Exception("请检查配置文件中的table属性值！");
    //得到所有property元素,并取得property元素的column属性值
    NodeList nodelist = subroot.getElementsByTagName("property");
    int len =  nodelist.getLength();
    columns = new String[len];
    classFileds = new String[len];
    for (int i = 0; i <len; i++) {
      Element temp = (Element)nodelist.item(i);
      columns[i] = temp.getAttribute("column");
      classFileds[i] = temp.getAttribute("name");
    }
    return new Object[]{className,columns,classFileds};
  }
  public static void main(String args[]) throws Exception{
    String file = "classes/conf/wb_relationdetail.xml";
    XMLParserUtil parser = new XMLParserUtil(file);
    Object[] temp = parser.getFieldAndColumnMapping("wb_relationdetail");
    ///////////////////////
    System.out.println("class name = "+ temp[0]);
    ////////////////////////////////////
    Object[] columns = (Object[])temp[1];
    for(int i=0,len = columns.length; i<len ; i++)
    {
      System.out.println("column name = " + columns[i]);
    }
    ///////////////
    Object[] fields = (Object[])temp[2];
    for(int i=0,len = fields.length; i<len ; i++)
    {
      System.out.println("field name = " + fields[i]);
    }
    //testReflect((String)temp[0]);
  }
//  private static  void testReflect(String className)throws Exception
//  {
//
//    Object ob = Class.forName(className).newInstance();
//    Class obClass = ob.getClass();
//    Method[] methods = obClass.getMethods();
//    for (int i = 0, len = methods.length; i < len; i++) {
//      Method method = methods[i];
//
//    }
//  }
}