dom4j的读写xml文件，读写xml字符串

百度了一些博客，大同小异，在选取jar包工具的时候大概看了下，大抵是jdom原始，dom4j优秀。于是做了些练习。

参考：http://www.cnblogs.com/mengdd/archive/2013/06/05/3119927.html

 package com.test.xml;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.util.List;

 import java.util.Random;

 import org.dom4j.Document;

 import org.dom4j.DocumentException;

 import org.dom4j.DocumentHelper;

 import org.dom4j.Element;

 import org.dom4j.io.OutputFormat;

 import org.dom4j.io.SAXReader;

 import org.dom4j.io.XMLWriter;

 /**

 * @ClassName: TestDom4j

 * @Description:dom4j练习xml的读写

 * @author mrf

 * @date 2015-11-11 下午02:25:20

 *

  */

 public class TestDom4j {

     /**

     * @Title: read

     * @Description:读取xml文件

     * @param @param path    参数

     * @return void    返回类型

      * @throws DocumentException

      */

     public static void read(String path) throws DocumentException{

         SAXReader saxReader = new SAXReader();

         Document doc = saxReader.read(new File(path));

         //获取根元素

         Element root = doc.getRootElement();

         System.out.println(root.getName()+root.attributeValue("name"));

         //获取子元素

         @SuppressWarnings("unchecked")

         List<Element> grades = root.elements();

         if(!grades.isEmpty()){

             for (int i = 0; i < grades.size(); i++) {

                 Element element = grades.get(i);

                 System.out.println(element.getName()+element.attributeValue("name"));

                 @SuppressWarnings("unchecked")

                 List<Element> classes = element.elements();

                 if(classes.size()>0){

                     for (int j = 0; j < classes.size(); j++) {

                         Element cls = classes.get(j);

                         @SuppressWarnings("unchecked")

                         List<Element> stus = cls.elements();

                         if(!stus.isEmpty()){

                             for (int k = 0; k < stus.size(); k++) {

                                 Element stu = stus.get(k);

                                 System.out.println(stu.getName()+stu.attributeValue("name"));

                                 //以下证明elements方法返回值不会为null,另查看源码发现也是直接创建list

 //                                List list = stu.elements();

 //                                System.out.println(list==null);

 //                                System.out.println(list.size());

 //                                System.out.println(list);

                             }

                         }

                     }

                 }

             }

         }

     }

     /**

     * @Title: getRandoStr

     * @Description:获取一个随机字符串

     * @param @param len

     * @param @return    参数

     * @return String    返回类型

      */

     public static String getRandoStr(int len){

         String base = "abcdefghijklmnopqrstuvwxyz1234567890";

         Random random = new Random();

         StringBuilder sb = new StringBuilder();

         for (int i = 0; i < len; i++) {

             sb.append(base.charAt(random.nextInt(base.length())));

         }

         return sb.toString();

     }

     /**

     * @Title: write

     * @Description: 测试写一个school文件

     * @param @throws IOException    参数

     * @return void    返回类型

      */

     public static void write(String path) throws IOException{

         //创建doc文档

         Document doc = DocumentHelper.createDocument();

         Element root = DocumentHelper.createElement("school");

         //设置根元素

         doc.setRootElement(root);

         //添加属性

         root.addAttribute("name","实验中学");

         root.addAttribute("position","河北石家庄");

         Element grade = root.addElement("grade");

         grade.addAttribute("name", "年级");

         grade.addAttribute("size", "1");

         Element cls = grade.addElement("class");

         cls.addAttribute("name", "班级");

         cls.addAttribute("size", "70");

         Element stu = cls.addElement("student");

         stu.addAttribute("name", getRandoStr(4));

         stu.addAttribute("age", 13+"");

         stu.addAttribute("sex", new Random().nextInt(2)+"");

         stu.setText("学生");

 //        //添加三个子节点初一初二初三

 //        for (int i = 1; i < 4; i++) {

 //            Element grade = root.addElement("grade");

 //            grade.addAttribute("name", "grade_"+i);

 //            grade.addAttribute("size", "20");

 //            //添加20个班级

 //            for (int j = 1; j < 21; j++) {

 //                Element cls = grade.addElement("class");

 //                cls.addAttribute("name", "grade_"+i+"_class_"+j);

 //                cls.addAttribute("size", "70");

 //                //添加70个学生

 //                for (int k = 1; k < 71; k++) {

 //                    Element stu = cls.addElement("student");

 //                    stu.addAttribute("name", getRandoStr(4));

 //                    stu.addAttribute("age", 12+i+"");

 //                    stu.addAttribute("sex", new Random().nextInt(2)+"");

 //                    stu.setText("学生");

 //                }

 //            }

 //        }

         //输出

         //控制台

         new XMLWriter().write(doc);

         //文件

         //格式 -缩进\t true表示换行

         OutputFormat format = new OutputFormat("\t",true);

         XMLWriter writer = new XMLWriter(new FileOutputStream(path),format);

         writer.write(doc);

         writer.flush();

         writer.close();

     }

     //解析xml字符串

     public static Document parseStr(String xmlStr) throws DocumentException{

         Document doc = DocumentHelper.parseText(xmlStr);

         return doc;

     }

     public static void main(String[] args) throws IOException, DocumentException {

 //        write("src/main/java/com/test/xml/school.xml");

         read("src/main/java/com/test/xml/school.xml");

     }

 }