xml转换

package util;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

import entity.Emp;

/**
* 员工XML解析器
*/
public class EmpXmlParser {

/** * 1.写XML，将员工数据写入到emp.xml中 */public static void emp2xml()     throws Exception {    //模拟员工数据    Emp e = new Emp();    e.setId(1);    e.setName("张三");    e.setAge(25);    e.setSalary(6000.00);    e.setType("simple");    //创建文档对象    Document doc =         DocumentHelper.createDocument();    //创建根元素    Element root = doc.addElement("emp");    //在根元素下创建各子元素    root.addElement("id").addText(            e.getId().toString());    root.addElement("name").addText(            e.getName());    root.addElement("age").addText(            e.getAge().toString());    root.addElement("salary").addText(            e.getSalary().toString());    //创建根元素的属性    root.addAttribute("type", e.getType());    //将文档对象输出    XMLWriter writer = new XMLWriter(            new FileOutputStream("d:\\xml\\emp.xml"),            OutputFormat.createPrettyPrint());    writer.write(doc);    writer.close();}/** * 2.读取XML，将数据写入Emp对象中 */public static void xml2emp() throws Exception {    SAXReader reader = new SAXReader();    //读取xml    Document doc = reader.read(            new FileInputStream(                    "d:\\xml\\emp.xml"));    Emp e = new Emp();    //读取根元素    Element root = doc.getRootElement();    //读取根元素的下级元素    e.setId(Integer.valueOf(            root.elementText("id")));    e.setName(root.elementText("name"));    e.setAge(Integer.valueOf(            root.elementText("age")));    e.setSalary(Double.valueOf(            root.elementText("salary")));    //读取根元素的属性    e.setType(root.attributeValue("type"));    System.out.println("ID:" + e.getId());    System.out.println("Name:" + e.getName());    System.out.println("Age:" + e.getAge());    System.out.println("Salary:" + e.getSalary());    System.out.println("Type:" + e.getType());}/** * 将一组Emp数据写入到一个XML文件中 */public static void emps2xml() throws Exception {    List<Emp> emps = new ArrayList<Emp>();    Emp e1 = new Emp();    e1.setId(1);    e1.setName("张三");    e1.setAge(25);    e1.setSalary(6000.00);    e1.setType("simple");    emps.add(e1);    Emp e2 = new Emp();    e2.setId(2);    e2.setName("李四");    e2.setAge(26);    e2.setSalary(7000.00);    e2.setType("simple");    emps.add(e2);    Emp e3 = new Emp();    e3.setId(3);    e3.setName("王五");    e3.setAge(27);    e3.setSalary(8000.00);    e3.setType("Leader");    emps.add(e3);    Document doc =         DocumentHelper.createDocument();    //创建根元素    Element root = doc.addElement("emps");    for(Emp emp : emps){        Element parent = root.addElement("emp");        parent.addElement("id").addText(                emp.getId().toString());        parent.addElement("name").addText(                emp.getName());        parent.addElement("age").addText(                emp.getAge().toString());        parent.addElement("salary").addText(                emp.getSalary().toString());        parent.addAttribute("type", emp.getType());    }    //输入到XML    XMLWriter writer = new XMLWriter(            new FileOutputStream("d:\\xml\\emps.xml")            ,OutputFormat.createPrettyPrint());    writer.write(doc);    writer.close();}/** * 4.从XML中读取一组Emp数据 */public static void xml2emps() throws Exception {    SAXReader reader = new SAXReader();    List<Emp> emps = new ArrayList<Emp>();    //读取XML文件    Document doc = reader.read(            new FileInputStream(                    "d:\\xml\\emps.xml"));    //读取根元素emps    Element root = doc.getRootElement();    List<Element> elems = root.elements("emp");    for(Element elem : elems){        Emp e = new Emp();        e.setId(Integer.valueOf(                elem.elementText("id")));        e.setName(elem.elementText("name"));        e.setAge(Integer.valueOf(                elem.elementText("age")));        e.setSalary(Double.valueOf(                elem.elementText("salary")));        e.setType(elem.attributeValue("type"));        emps.add(e);    }    for(Emp e : emps){        System.out.println(            e.getId() + " " +e.getName()            );    }}/** * xpath演示示例 */public static void xpath() throws Exception {    SAXReader reader = new SAXReader();    Document doc = reader.read(                new FileInputStream(                        "d:\\xml\\emps.xml"));

// List elems =
// doc.selectNodes(“/emps/emp[1]”);
// List elems =
// doc.selectNodes(“/emps/emp[@type=’Leader’]”);
List elems =
doc.selectNodes(“/emps/emp[id=’2’]”);
Element parent = elems.get(0);
System.out.println(parent.elementText(“id”));
System.out.println(parent.elementText(“name”));
}

public static void main(String[] args)    throws Exception {

// emp2xml();
// xml2emp();
// emps2xml();
// xml2emps();
xpath();
}

}