XML文件的增删改查操作（java实现）

xml的初始化及增删改查操作：

//初始化
   private void btnInitActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_btnInitActionPerformed
       // TODO add your handling code here:
       try {
           File file = new File("books.xml");
           DocumentBuilderFactory docFactory = DocumentBuilderFactory.
                                               newInstance();
           DocumentBuilder builder = docFactory.newDocumentBuilder();

           if (!file.exists()) {
               doc = builder.newDocument();
               Element books = doc.createElement("books");
               doc.appendChild(books);
           } else {
               doc = builder.parse(file);
           }
           this.jTextArea1.setText("初始化完成");
       } catch (Exception ex) {
           this.jTextArea1.setText("初始化失败");
       }
   }//GEN-LAST:event_btnInitActionPerformed

   private void btnSaveActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_btnSaveActionPerformed
       // TODO add your handling code here:
       try {
           TransformerFactory tfactory = TransformerFactory.newInstance();
           Transformer transformer = tfactory.newTransformer();
           transformer.setOutputProperty(OutputKeys.INDENT, "yes");

           DOMSource source = new DOMSource(doc);
           StreamResult result = new StreamResult(new File("books.xml"));

           transformer.transform(source, result);

           this.jTextArea1.setText("保存成功");
       } catch (Exception ex) {
           this.jTextArea1.setText("保存失败");
       }
   }//GEN-LAST:event_btnSaveActionPerformed

   private void btnShowActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_btnShowActionPerformed
       // TODO add your handling code here:
       if (doc != null) {
           Element books = doc.getDocumentElement();
           this.jTextArea1.setText(books.getNodeName());

           NodeList nl = null;
           nl = books.getChildNodes();
           for (int i = 0; i < nl.getLength(); i++) {
               Node node = nl.item(i);
               //节点类型,元素1/属性2/文本3/注释8/文档9
               if (node.getNodeType() == 1) {
                   this.jTextArea1.append("\n\t" + node.getNodeName());
                   NodeList nsubs = node.getChildNodes();
                   for (int j = 0; j < nsubs.getLength(); j++) {
                       if (nsubs.item(j).getNodeType() == 1 &&
                           nsubs.item(j).getFirstChild() != null) {
                           this.jTextArea1.append("\n\t\t" +
                                   nsubs.item(j).getNodeName() + " : " +
                                   nsubs.item(j).getFirstChild().
                                   getNodeValue());
                       }
                   }
               }
           }
       }
   }//GEN-LAST:event_btnShowActionPerformed

   private void btnShow2ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_btnShow2ActionPerformed
       // TODO add your handling code here:
       String msg = "";
       if (doc != null){
           NodeList nl = doc.getElementsByTagName("*");
          
           for (int i=0;i<nl.getLength();i++){
               Element e = (Element)nl.item(i);

               //得到属性
               NamedNodeMap nnm = e.getAttributes();
               msg += "元素：" + e.getNodeName() +":" + e.getFirstChild().getNodeValue() + "\n";

               for (int k=0;k<nnm.getLength();k++){
                   Attr att = (Attr)nnm.item(k);
                   msg += "\t属性有\t"+ att.getNodeName() + ":" + att.getNodeValue()+"\n";
               }
           }
       }
       this.jTextArea1.setText(msg);
   }//GEN-LAST:event_btnShow2ActionPerformed

   private void btnSearchActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_btnSearchActionPerformed
       // TODO add your handling code here:
       Node node = Search(this.jTextField1.getText());
       if (node != null) {
           this.jTextArea1.setText("找到了此元素");
           this.jTextArea1.append("\n\t书籍编号 \t: " + this.jTextField1.getText());
           NodeList list = node.getChildNodes();
           for (int i = 0; i < list.getLength(); i++) {
               Node sub = list.item(i);
               if (sub.getNodeType() == 1 && sub.getFirstChild() != null) {
                   this.jTextArea1.append("\n\t" + sub.getNodeName() + " \t: " +
                                          sub.getFirstChild().getNodeValue());
               }
           }
       }
       else {
           this.jTextArea1.setText("找不到此元素");
       }
   }//GEN-LAST:event_btnSearchActionPerformed

   private void btnAddActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_btnAddActionPerformed
       // TODO add your handling code here:

       try {
           //创建元素
           Element elemBook = doc.createElement("book");
           //添加到根元素底下
           doc.getDocumentElement().appendChild(elemBook);

           //为book元素设置属性
           Attr attrId = doc.createAttribute("id"); //创建
           attrId.setNodeValue(this.jTextField1.getText()); //设置值
           elemBook.setAttributeNode(attrId); //设置到book元素

           //为book元素添加子元素name
           Element elemNode = doc.createElement("name"); //创建
           Text textNode = doc.createTextNode(this.jTextField2.getText()); //创建文本节点
           elemNode.appendChild(textNode); //为name子元素指定文本
           elemBook.appendChild(elemNode); //添加为book的子元素

           //为book元素添加子元素price
           elemNode = doc.createElement("price"); //创建
           textNode = doc.createTextNode(this.jTextField3.getText()); //创建文本节点
           elemNode.appendChild(textNode); //为price子元素指定文本
           elemBook.appendChild(elemNode); //添加为book的子元素

           //为book元素添加子元素pub
           elemNode = doc.createElement("pub"); //创建
           textNode = doc.createTextNode(this.jTextField4.getText()); //创建文本节点
           elemNode.appendChild(textNode); //为pub子元素指定文本
           elemBook.appendChild(elemNode); //添加为book的子元素

           //为book元素添加子元素author
           elemNode = doc.createElement("author"); //创建
           textNode = doc.createTextNode(this.jTextField5.getText()); //创建文本节点
           elemNode.appendChild(textNode); //为author子元素指定文本
           elemBook.appendChild(elemNode);

           this.jTextArea1.setText("添加成功");
       } catch (Exception ex) {
           this.jTextArea1.setText("添加失败");
       }
   }//GEN-LAST:event_btnAddActionPerformed

   private void btnModifyActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_btnModifyActionPerformed
       // TODO add your handling code here:
       Node node = Search(this.jTextField1.getText());
       String[] values = {this.jTextField2.getText(), this.jTextField3.getText(),
                         this.jTextField4.getText(), this.jTextField5.getText()};
       if (node != null) {
           NodeList nl = node.getChildNodes();
           int k = 0;
           for (int i = 0; i < nl.getLength(); i++) {
               Node n = nl.item(i);
               if (n.getNodeType() == 1) {
                   Node newNode = doc.createTextNode(values[k]);
                   if (n.getFirstChild() != null) {
                       n.replaceChild(newNode, n.getFirstChild());
                   } else {
                       n.appendChild(newNode);
                   }
                   k = k + 1;
               }
           }
           this.jTextArea1.setText("修改成功");
       } else {
           this.jTextArea1.setText("找不到要修改的节点");
       }
   }//GEN-LAST:event_btnModifyActionPerformed

   private void btnDelActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_btnDelActionPerformed
       // TODO add your handling code here:
       Node node = Search(this.jTextField1.getText());
       if (node != null) {
           Node parent = node.getParentNode();
           parent.removeChild(node);

           this.jTextArea1.setText("删除成功");
       } else {
           this.jTextArea1.setText("找不到要删除的节点");
       }
   }//GEN-LAST:event_btnDelActionPerformed

   private Node Search(String id) {
       Node node = null;
       Element books = doc.getDocumentElement();
       NodeList nl = null;
       if (books.hasChildNodes()) {
           nl = books.getChildNodes();
           for (int i = 0; i < nl.getLength(); i++) {
               node = nl.item(i);
               if (node.getNodeType() == 1) {
                   Element ele = (Element) node;
                   if (ele.getAttribute("id").equals(id)) {
                       return node;
                   }
               }
           }
       }
       return null;
   }