java中采用dom4j解析xml文件

一.前言

   在最近的开发中用到了dom4j来解析xml文件，以前听说过来解析xml文件的几种标准方式；但是从来的没有应用过来，所以可以在google中搜索dmo4j解析xml文件的方式，学习一下dom4j解析xml的具体操作。

二.代码详情

   dom4j是一个第三方开发组开发出的插件，所以在我们使用dom4jf的时候我们要去下载一下dom4j对应版本的jar导入在我们项目中。

 1)xml文件:

1 2 3 4 5 6 7 8 9 10 11

"1.0" encoding="UTF-8"?>    "001">              J K. Rowling        "002">              Erik T. Ray

示例一：用List列表的方式来解析xml

SAXReader就是一个管道，用一个流的方式，把xml文件读出来

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

import java.io.File; import java.util.List;    import org.dom4j.Attribute; import org.dom4j.Document; import org.dom4j.Element; import org.dom4j.io.SAXReader;          public class Demo {        public static void main(String[] args) throws Exception {         SAXReader reader = new SAXReader();         File file = new File("books.xml");         Document document = reader.read(file);         Element root = document.getRootElement();         List childElements = root.elements();         for (Element child : childElements) {             //未知属性名情况下             /*List attributeList = child.attributes();             for (Attribute attr : attributeList) {                 System.out.println(attr.getName() + ": " + attr.getValue());             }*/                            //已知属性名情况下             System.out.println("id: " + child.attributeValue("id"));                            //未知子元素名情况下             /*List elementList = child.elements();             for (Element ele : elementList) {                 System.out.println(ele.getName() + ": " + ele.getText());             }             System.out.println();*/                            //已知子元素名的情况下             System.out.println("title" + child.elementText("title"));             System.out.println("author" + child.elementText("author"));             //这行是为了格式化美观而存在             System.out.println();         }     }    }

示例二：使用Iterator迭代器的方式来解析xml

 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

import java.io.File; import java.util.Iterator;    import org.dom4j.Attribute; import org.dom4j.Document; import org.dom4j.Element; import org.dom4j.io.SAXReader;          public class Demo {     public static void main(String[] args) throws Exception {         SAXReader reader = new SAXReader();         Document document = reader.read(new File("books.xml"));         Element root = document.getRootElement();                    Iterator it = root.elementIterator();         while (it.hasNext()) {             Element element = (Element) it.next();                            //未知属性名称情况下             /*Iterator attrIt = element.attributeIterator();             while (attrIt.hasNext()) {                 Attribute a  = (Attribute) attrIt.next();                 System.out.println(a.getValue());             }*/                            //已知属性名称情况下             System.out.println("id: " + element.attributeValue("id"));                            //未知元素名情况下             /*Iterator eleIt = element.elementIterator();             while (eleIt.hasNext()) {                 Element e = (Element) eleIt.next();                 System.out.println(e.getName() + ": " + e.getText());             }             System.out.println();*/                            //已知元素名情况下             System.out.println("title: " + element.elementText("title"));             System.out.println("author: " + element.elementText("author"));             System.out.println();         }     } }

运行结果：

 示例三：创建xml文档并输出到文件

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

import java.io.File; import java.io.FileOutputStream;    import org.dom4j.Document; import org.dom4j.DocumentHelper; import org.dom4j.Element; import org.dom4j.io.OutputFormat; import org.dom4j.io.XMLWriter;       public class Demo {     public static void main(String[] args) throws Exception {         Document doc = DocumentHelper.createDocument();         //增加根节点         Element books = doc.addElement("books");         //增加子元素         Element book1 = books.addElement("book");         Element title1 = book1.addElement("title");         Element author1 = book1.addElement("author");                    Element book2 = books.addElement("book");         Element title2 = book2.addElement("title");         Element author2 = book2.addElement("author");                    //为子节点添加属性         book1.addAttribute("id", "001");         //为元素添加内容         title1.setText("Harry Potter");         author1.setText("J K. Rowling");                    book2.addAttribute("id", "002");         title2.setText("Learning XML");         author2.setText("Erik T. Ray");                    //实例化输出格式对象         OutputFormat format = OutputFormat.createPrettyPrint();         //设置输出编码         format.setEncoding("UTF-8");         //创建需要写入的File对象         File file = new File("D:" + File.separator + "books.xml");         //生成XMLWriter对象，构造函数中的参数为需要输出的文件流和格式         XMLWriter writer = new XMLWriter(new FileOutputStream(file), format);         //开始写入，write方法中包含上面创建的Document对象         writer.write(doc);     } }

运行结果：