orderprocessor.java~24~

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("status");
    for (int orderNum = 0;
         orderNum < orders.getLength();
         orderNum++) {
      System.out.println(orders.item(orderNum)
                         .getFirstChild().getNodeValue());
    }
    //////////////////////////////
    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);
    }
  }

}