orderprocessor.java~25~

一个很好xml学习样例

package xmltest;

import javax.xml.parsers.*;
import org.w3c.dom.*;
import java.io.*;

public class OrderProcessor {
  public static void main(String[] args) {
    File docFile = new File("orders.xml");
    Document doc = null;
    Document newdoc = null;
    try {
      DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
      DocumentBuilder db = dbf.newDocumentBuilder();
      doc = db.parse(docFile);
      newdoc = db.newDocument();
    }
    catch (Exception e) {
      System.out.print("Problem parsing the file: " + e.getMessage());
    }
    Element root = doc.getDocumentElement();
    changeOrder(root, "status", "processing");
    NodeList orders = root.getElementsByTagName("order");
    for (int orderNum = 0;
         orderNum < orders.getLength();
         orderNum++) {

      Element thisOrder = (Element) orders.item(orderNum);
      NodeList orderItems = thisOrder.getElementsByTagName("item");
      double total = 0;
      for (int itemNum = 0;
           itemNum < orderItems.getLength();
           itemNum++) {

        // Total up cost for each item and
        // add to the order total

        //Get this item as an Element
        Element thisOrderItem = (Element) orderItems.item(itemNum);
        //Get pricing information for this Item
        String thisPrice =
            thisOrderItem.getElementsByTagName("price").item(0)
            .getFirstChild().getNodeValue();
        double thisPriceDbl = new Double(thisPrice).doubleValue();

        //Get quantity information for this Item
        String thisQty =
            thisOrderItem.getElementsByTagName("qty").item(0)
            .getFirstChild().getNodeValue();
        double thisQtyDbl = new Double(thisQty).doubleValue();
        double thisItemTotal = thisPriceDbl * thisQtyDbl;
        total = total + thisItemTotal;
      }
      String totalString = new Double(total).toString();

      //////////////////////////////
      Element newRoot = newdoc.createElement("processedOrders");
      NodeList processOrders = doc.getElementsByTagName("order");
      for (int orderNum = 0;
           orderNum < processOrders.getLength();
           orderNum++) {
        Element thisOrder = (Element) processOrders.item(orderNum);

        Element customerid =
            (Element) thisOrder.getElementsByTagName("customerid")
            .item(0);
        String limit = customerid.getAttributeNode("limit").getNodeValue();

        String total = thisOrder.getElementsByTagName("total").item(0)
            .getFirstChild().getNodeValue();

        double limitDbl = new Double(limit).doubleValue();
        double totalDbl = new Double(total).doubleValue();
        Element newOrder = newdoc.createElement("order");

        Element newStatus = newdoc.createElement("status");
        if (totalDbl > limitDbl) {
          newStatus.appendChild(newdoc.createTextNode("REJECTED"));
        }
        else {
          newStatus.appendChild(newdoc.createTextNode("PROCESSED"));
        }

        Element newCustomer = newdoc.createElement("customerid");
        String oldCustomer = customerid.getFirstChild().getNodeValue();
        newCustomer.appendChild(newdoc.createTextNode(oldCustomer));

        Element newTotal = newdoc.createElement("total");
        newTotal.appendChild(newdoc.createTextNode(total));

        newOrder.appendChild(newStatus);
        newOrder.appendChild(newCustomer);
        newOrder.appendChild(newTotal);

        newRoot.appendChild(newOrder);
      }

      newdoc.appendChild(newRoot);

      System.out.print(newRoot.toString());

      File newFile = new File("processedOrders.xml");
      try {
        FileWriter newFileStream = new FileWriter(newFile);
        newFileStream.write("<?xml version='1.0'?>");
        newFileStream.write("<!DOCTYPE " + doc.getDoctype().getName() + " ");
        if (doc.getDoctype().getSystemId() != null) {
          newFileStream.write(" SYSTEM ");
          newFileStream.write(doc.getDoctype().getSystemId());
        }
        if (doc.getDoctype().getPublicId() != null) {
          newFileStream.write(" PUBLIC ");
          newFileStream.write(doc.getDoctype().getPublicId());
        }
        newFileStream.write(">");
        newFileStream.write(newRoot.toString());
        newFileStream.close();
      }
      catch (IOException ex) {
        ex.printStackTrace();
      }

      // Element root = doc.getDocumentElement();

//    stepThroughAll(root);
      // changeOrder(root, "status", "processing");
      // NodeList orders = root.getElementsByTagName("status");
      // for (int orderNum = 0;
      //    orderNum < orders.getLength();
      //  orderNum++) {
      //System.out.println(orders.item(orderNum)
      //                 .getFirstChild().getNodeValue());
      //}

    }

    private static void stepThrough(Node start) {

      System.out.println(start.getNodeName() + " = " + start.getNodeValue());

      for (Node child = start.getFirstChild();
           child != null;
           child = child.getNextSibling()) {
        stepThrough(child);

      }
    }

    private static void stepThroughAll(Node start) {
      System.out.println(start.getNodeName() + " = " + start.getNodeValue());
      if (start.getNodeType() == start.ELEMENT_NODE) {
        NamedNodeMap startAttr = start.getAttributes();
        for (int i = 0;
             i < startAttr.getLength();
             i++) {
          Node attr = startAttr.item(i);
          System.out.println("  Attribute:  " + attr.getNodeName()
                             + " = " + attr.getNodeValue());
        }
      }

      for (Node child = start.getFirstChild();
           child != null;
           child = child.getNextSibling()) {
        stepThroughAll(child);
      }
    }

    private static void changeOrder(Node start,
                                    String elemName,
                                    String elemValue) {
      if (start.getNodeName().equals(elemName)) {
        start.getFirstChild().setNodeValue(elemValue);
      }

      for (Node child = start.getFirstChild();
           child != null;
           child = child.getNextSibling()) {
        changeOrder(child, elemName, elemValue);
      }
    }

  }