文章标题

package cn.itcast.dom4j;

import java.io.File;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

// 查询出所有学生的所有信息
public class Demo2_2 {
public static void main(String[] args) {
try {
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/students.xml"));
//1.获得根元素
Element root = document.getRootElement();
String name2 = root.getName();
//2.迭代根元素下的所有名叫student的子元素
List<Element> list = root.elements("student");
for(Element student : list){
//3.获得student元素的number属性
String number = student.attributeValue("number");
//4.student子元素的内容(name age sex)
String name = student.elementText("name");
String age = student.elementText("age");
String sex = student.elementText("sex");

System.out.println("当前学生的学号是"+number+",姓名是:"+name+",年龄是:"+age+",性别是"+sex+"");
}

} catch (Exception e) {
e.printStackTrace();
}
}
}

package cn.itcast.dom4j;

import java.io.File;
import java.util.Iterator;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

// 查询出所有学生的所有信息
public class Demo2 {
public static void main(String[] args) {
try {
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/students.xml"));
//1.获得根元素
Element root = document.getRootElement();
//2.迭代根元素下的所有名叫student的子元素
for(Iterator<Element> it = root.elementIterator("student");it.hasNext();){
Element student = it.next();
//3.获得student元素的number属性
String number = student.attributeValue("number");
//4.student子元素的内容(name age sex)
String name = student.elementText("name");
String age = student.elementText("age");
String sex = student.elementText("sex");

System.out.println("当前学生的学号是"+number+",姓名是:"+name+",年龄是:"+age+",性别是"+sex+"");
}

} catch (Exception e) {
e.printStackTrace();
}
}
}

package cn.itcast.dom4j;

import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintWriter;

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

// 增加一个学生元素. jack itcast_0003 19 male
public class Demo3 {
public static void main(String[] args) {
SAXReader reader = new SAXReader();
try {
Document document = reader.read(new File("src/students.xml"));

//1 获得根元素
Element root = document.getRootElement();
//2 添加Element,添加number属性,
Element studentEle = root.addElement("student").addAttribute("number", "itcast_0003");
//3 添加name age sex 子元素并添加子元素中的文本
studentEle.addElement("name").addText("张三");
studentEle.addElement("age").addText("19");

studentEle.addElement("sex").addText("male");

//4 将document对象写到文件中.
//创建格式化器
OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("UTF-8");
//创建写入器
//XMLWriter writer = new XMLWriter(new FileWriter("src/students_copy.xml"),format);
XMLWriter writer = new XMLWriter(new FileOutputStream("src/students_copy.xml"),format);
//写入
writer.write(document);
//关闭资源
writer.close();

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

package cn.itcast.dom4j;

import java.io.File;
import java.io.FileOutputStream;

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

// 删除一个学生 itcast_0001
public class Demo4 {
public static void main(String[] args) {
SAXReader reader = new SAXReader();
try {
Document document = reader.read(new File("src/students.xml"));
//1 获得根元素
Element root = document.getRootElement();
//使用xpath找到我们需要元素
//定义xpath
String xpath = "//student[@number='itcast_0001']";
Element student =  (Element) document.selectSingleNode(xpath);
//删除
System.out.println(student.getParent().remove(student));

//回写
XMLWriter writer = new XMLWriter(new FileOutputStream("src/students_copy.xml"), OutputFormat.createPrettyPrint());

writer.write(document);

writer.close();

//下面这个思路可以.但是效率太低.
//2 获得所有学生元素
//3 遍历
//判断=>number属性是否为要删除的
//是==>删除
//不是
//4 回写
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

package cn.itcast.dom4j;

import java.io.File;
import java.io.FileOutputStream;

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

//修改一个学生 itcast_0001 ==>  rose  16  female
public class Demo5 {
public static void main(String[] args) {
SAXReader reader = new SAXReader();
try {
Document document = reader.read(new File("src/students.xml"));
//1.定义xpath表达式
String xpath ="//student[@number='itcast_0001']";

//2.使用xpath查找

Element studentEle = (Element) document.selectSingleNode(xpath);
//3.修改student元素的子元素的name ,age .sex内容

studentEle.element("name").setText("rose");
studentEle.element("age").setText("16");
studentEle.element("sex").setText("female");

//回写
XMLWriter writer = new XMLWriter(new FileOutputStream("src/students_copy.xml"), OutputFormat.createPrettyPrint());

writer.write(document);

writer.close();

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

<?xml version="1.0" encoding="utf-8" ?>
<students>
<student number="itcast_0001">
<name>tom</name>
<age>18</age>
<sex>male</sex>
</student>
<student number="itcast_0002">
<name>jerry</name>
<age>16</age>
<sex>female</sex>
</student>
</students>