xPath用法

XPath基于XML的树状结构，提供在数据结构树中找寻节点的能力，下面是一小示例,需要的朋友可以参考下

 

 

XPath即为XML路径语言（XML Path Language），它是一种用来确定XML文档中某部分位置的语言。XPath基于XML的树状结构，提供在数据结构树中找寻节点的能力。起初 XPath 的提出的初衷是将其作为一个通用的、介于XPointer与XSL间的语法模型。但是 XPath 很快的被开发者采用来当作小型查询语言。

XPathTest.java

?

package com.hongyuan.test;

  

 

import java.io.File;

import java.io.IOException;

 

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.xpath.XPath;

import javax.xml.xpath.XPathConstants;

import javax.xml.xpath.XPathExpressionException;

import javax.xml.xpath.XPathFactory;

 

import org.w3c.dom.Document;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

 

public class XPathTest {

 

 public static void main(String[] args) throws ParserConfigurationException,

   SAXException, IOException, XPathExpressionException {

 

  // 解析文件，生成document对象

  DocumentBuilder builder = DocumentBuilderFactory.newInstance()

    .newDocumentBuilder();

  Document document = builder.parse(new File("bookstore.xml"));

 

  // 生成XPath对象

  XPath xpath = XPathFactory.newInstance().newXPath();

 

  // 获取节点值

  String webTitle = (String) xpath.evaluate(

    "/bookstore/book[@category='WEB']/title/text()", document,

    XPathConstants.STRING);

  System.out.println(webTitle);

 

  System.out.println("===========================================================");

 

  // 获取节点属性值

  String webTitleLang = (String) xpath.evaluate(

    "/bookstore/book[@category='WEB']/title/@lang", document,

    XPathConstants.STRING);

  System.out.println(webTitleLang);

 

  System.out.println("===========================================================");

 

  // 获取节点对象

  Node bookWeb = (Node) xpath.evaluate(

    "/bookstore/book[@category='WEB']", document,

    XPathConstants.NODE);

  System.out.println(bookWeb.getNodeName());

 

  System.out.println("===========================================================");

 

  // 获取节点集合

  NodeList books = (NodeList) xpath.evaluate("/bookstore/book", document,

    XPathConstants.NODESET);

  for (int i = 0; i < books.getLength(); i++) {

   Node book = books.item(i);

   System.out.println(xpath.evaluate("@category", book,

     XPathConstants.STRING));

  }

 

  System.out.println("===========================================================");

 }

 

}

 

  

 

bookstore.xml

 

复制代码代码如下:

 

<?xml version="1.0" encoding="utf-8" ?>

<bookstore>

 <book category="COOKING">

   <title lang="en">Everyday Italian</title>

   <author>Giada De Laurentiis</author>

   <year>2005</year>

   <price>30.00</price>

 </book>

 <book category="CHILDREN">

   <title lang="en">Harry Potter</title>

   <author>J K. Rowling</author>

   <year>2005</year>

   <price>29.99</price>

 </book>

 <book category="WEB">

   <title lang="en">Learning XML</title>

   <author>Erik T. Ray</author>

   <year>2003</year>

   <price>39.95</price>

 </book>

</bookstore>

　　

InputStream inputStream = new ByteArrayInputStream(responseXML.trim().getBytes("UTF-8"));
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(inputStream);
XPath xpath = XPathFactory.newInstance().newXPath();
setResponseCode((xpath.evaluate("/InterBOSS/SvcCont/AdditionRsp/Status", doc)));
String ordNum = (xpath.evaluate("/InterBOSS/SvcCont/AdditionRsp/OperSeqList/OperSeq", doc));
setResponseContent((xpath.evaluate("/InterBOSS/SvcCont/AdditionRsp/ErrDesc", doc)));

 

运行效果