java 之 xml 之解析工具jaxp

一、jaxp的api查看
  *jaxp是javase一部分
  *jaxp解析器在jdk的javax.xml.parsers包里面
      *共四个类：分别针对dom和sax解析使用的类
      *dom解析类：
               DocumentBuilder:解析器类
                  *这个一个抽象类，不能new
                  *得到方式：DocumentBuilderFactory.newDocumentBuild();
                  *包含的方法： 
                     可以解析xml:parser(String uri) uri:文件路径  返回Document对象
                  *返回的Document是一个接口，父节点是Node,若在Document找不到的方法，可以在Node找
                  *Document的方法：
                      *getElementsByTagName(String tagname)：可以得到标签，返回集合NodeList
                      *createElement(String tagName): 创建标签
                      *createTextNode(String data):创建文本
                  *Node的方法    
                      *appendChild(Node newChild):把文本添加到标签下面
                      *removeChild(Node oldChild):删除节点
                      *getParentNode():获取父节点
                  *NodeList的方法
                      *getLength()：得到集合的长度
                      *item(int index)下标获取到具体的值
                      *案例：
                          for(int i=0;i<list.getLength;i++){list.item(i);
               DocumentBuilderFactory:解析器工厂
      *sax解析器：
               SAXParser:解析器类
               SAXParserFactory:解析器工厂

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class TestJaxp {
    public static void main(String[] args) throws Exception
    {
        //查询所有name元素的值
        /**
         * 1、创建解析器工厂
         * 2、根据解析器工厂创建工厂
         * 3、解析xml返回document
         **/
        //创建解析工厂
        DocumentBuilderFactory buildFactory=DocumentBuilderFactory.newInstance();
        //创建解析器
        DocumentBuilder builder=buildFactory.newDocumentBuilder();
        //解析xml返回document
        Document document=builder.parse("src/person.xml");
        //得到所有元素节点
        NodeList nodeList=document.getElementsByTagName("name");
        //遍历读取元素内容
        for (int i = 0; i < nodeList.getLength(); i++) {
            Node name1=nodeList.item(i);
            String s=name1.getTextContent();//得到标签元素里面的内容
            System.out.println(s);
        }
        
    }
}



//添加
//1、创建解析器工厂
        //根据解析器工厂创建工厂
        //解析xml返回对象
        DocumentBuilderFactory buildFactory=DocumentBuilderFactory.newInstance();
        DocumentBuilder builder=buildFactory.newDocumentBuilder();
        Document document=builder.parse("src/test.xml");
        NodeList nodeList=document.getElementsByTagName("p1");
        Node p1=nodeList.item(0);
        Element sex1=document.createElement("sex");
        Text text1=document.createTextNode("女");
        sex1.appendChild(text1);
        p1.appendChild(sex1);
        
        TransformerFactory transformerFactory=TransformerFactory.newInstance();
        Transformer transformer=transformerFactory.newTransformer();
        transformer.transform(new DOMSource(document),new StreamResult("src/test.xml"));

//修改
//1、创建解析器工厂
        //根据解析器工厂创建工厂
        //解析xml返回对象
        DocumentBuilderFactory buildFactory=DocumentBuilderFactory.newInstance();
        DocumentBuilder builder=buildFactory.newDocumentBuilder();
        Document document=builder.parse("src/test.xml");
        Node node=document.getElementsByTagName("sex").item(0);
        node.setTextContent("男");
        
        TransformerFactory transformerFactory=TransformerFactory.newInstance();
        Transformer transformer=transformerFactory.newTransformer();
        transformer.transform(new DOMSource(document),new StreamResult("src/test.xml"));

//删除
//1、创建解析器工厂
        //根据解析器工厂创建工厂
        //解析xml返回对象
        DocumentBuilderFactory buildFactory=DocumentBuilderFactory.newInstance();
        DocumentBuilder builder=buildFactory.newDocumentBuilder();
        Document document=builder.parse("src/test.xml");
        Node node=document.getElementsByTagName("name").item(0);
        Node nodeParent=node.getParentNode();
        nodeParent.removeChild(node);
        TransformerFactory transformerFactory=TransformerFactory.newInstance();
        Transformer transformer=transformerFactory.newTransformer();
        transformer.transform(new DOMSource(document),new StreamResult("src/test.xml"));

//递归遍历
    //1、创建解析器工厂
        //根据解析器工厂创建工厂
        //解析xml返回对象
        DocumentBuilderFactory buildFactory=DocumentBuilderFactory.newInstance();
        DocumentBuilder builder=buildFactory.newDocumentBuilder();
        Document document=builder.parse("src/test.xml");
        list1(document);
    }

    private static void list1(Node node) {
        // TODO Auto-generated method stub
        if(node.getNodeType()==Node.ELEMENT_NODE)
        {
            System.out.println(node.getNodeName());
        }
        
        NodeList nodelist=node.getChildNodes();
        for (int i = 0; i < nodelist.getLength(); i++) {
            Node node1=nodelist.item(i);
            list1(node1);
        }
    }