一、Xml
1.Xml文档的读取方法
public class Test1 {
@Test//查询方法一
public void test1() throws Exception {
//1.创建一个解析器
SAXReader reader=new SAXReader();
//2.读取某个xml文件,返回xml对应的dom文档树
Document doc=reader.read("src\\xml\\msg.xml");
//3.获得根标签
Element root=doc.getRootElement();
System.out.println(root.getName());
//4.1 获取所有子标签
List<Element> msgs=root.elements();
for (Element msg : msgs) {
System.out.println(msg.getName());
}
//4.1 获取第一个子标签--2种方式
Element e=msgs.get(0);
System.out.println(e.getName());
Element ee=root.element("msg");
System.out.println(ee.getName());
//4.2使用迭代器获得子标签
Iterator it = e.elementIterator();
while (it.hasNext()){
Element e1=(Element) it.next();
System.out.println(e1.getName()+"--"+e1.getText());
}
}
@Test//查询方法二
public void test2() throws Exception {
//1.获取sax解析器对象
SAXReader reader = new SAXReader();
//2.读取某个xml文件--返回一个文档对象，表示整个xml文档树
Document doc = reader.read("src/xml1/a.xml");
//3.获取根标签
Element root = doc.getRootElement();
//4.逐级向下寻找标签
Element family1 = (Element) root.elements("family").get(0);
Element person1 = (Element)family1.elements("person").get(0);
Element age = person1.element("age");
System.out.println(age.getText());//获取标签的文本内容
}
}
2.Xml文档上对于标签的增加
@Test//新增(在原来的dom树上新增)
public void test2() throws Exception{
//一、构建文档树
//1.创建一个解析器
SAXReader reader=new SAXReader();
//2.读取某个xml文件,返回xml对应的dom文档树
Document doc=reader.read("src/xml/msg.xml");
//3.获得根标签
Element root = doc.getRootElement();
//4.给根标签加一个子标签
Element msg3 = root.addElement("msg3");
Element content = msg3.addElement("content");
content.setText("元旦快乐！");
//二、用新的文档树覆盖旧的文档树
//1.借助字节输出流
FileOutputStream out = new FileOutputStream("src/xml/msg.xml");
//2.需要一个格式美化对象
OutputFormat format=OutputFormat.createPrettyPrint();
//3.根据上面的2个对象,构建一个xml输出流对象
XMLWriter writer = new XMLWriter(out,format);
//4.将doc文档树 重新写入 xml文件中
writer.write(doc);
//5.关闭流--刷新缓冲区
writer.close();
}
3.创建一个新的Xml文档来进行标签和内容的增加
@Test//新增--场景2(创建新的dom树)
public void test3() throws Exception{
//1.创建一个文档对象--dom树
Document doc= DocumentHelper.createDocument();
//2.添加根元素
Element root = doc.addElement("heroes");
//3.添加子元素
Element hero = root.addElement("hero");
Element name = hero.addElement("name");
Element age = hero.addElement("age");
//给子元素设置文本
name.setText("曹操");
age.setText("26");
//将上面创建的dom树,写进一个xml文件中 字节输出流--指定xml文件路径 美化器,规范xml格式
XMLWriter xmlWriter = new XMLWriter(new FileOutputStream("src/xml/hero.xml"),OutputFormat.createPrettyPrint());
xmlWriter.write(doc);
}
data = pd.read_csv(
'https://labfile.oss.aliyuncs.com/courses/1283/adult.data.csv')
print(data.head())
4.将对象中的信息写入Xml文档中的案例：
package work.one;
public class Animal {
private String name;
private int age;
public Animal() {
}
public Animal(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
package work.one;
public class Elephant extends Animal {
private double weight;
public Elephant() {
}
public Elephant(double weight) {
this.weight = weight;
}
public Elephant(String name, int age, double weight) {
super(name, age);
this.weight = weight;
}
public double getWeight() {
return weight;
}
public void setWeight(double weight) {
this.weight = weight;
}
}
package work.one;
public class Monkey extends Animal{
private double height;
public Monkey() {
}
public Monkey(double height) {
this.height = height;
}
public Monkey(String name, int age, double height) {
super(name, age);
this.height = height;
}
public double getHeight() {
return height;
}
public void setHeight(double height) {
this.height = height;
}
}
package work.one;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import java.io.FileOutputStream;
import java.util.ArrayList;
public class Test1 {
public static void main(String[] args) throws Exception {
ArrayList<Animal> animals = new ArrayList<>();
animals.add(new Elephant("胖胖",2,1.3));
animals.add(new Elephant("肥仔",1,1.5));
animals.add(new Elephant("憨憨",3,1.8));
animals.add(new Monkey("星仔",3,0.8));
animals.add(new Monkey("狒狒",4,0.9));
animals.add(new Monkey("猴哥",5,1.0));
createXml(animals);
}
public static void createXml(ArrayList<Animal> animals) throws Exception {
//创建一个dom树
Document doc = DocumentHelper.createDocument();
//添加根节点
Element ani = doc.addElement("animals");
//遍历集合
for (int i = 0; i < animals.size(); i++) {
//添加子节点
Element a = ani.addElement("animal");
//给子节点添加子节点
Element name = a.addElement("name");
name.setText(animals.get(i).getName());
Element age = a.addElement("age");
//age.setText(Integer.toString(animals.get(i).getAge()));
//age.setText(String.valueOf(animals.get(i).getAge()));
age.setText(animals.get(i).getAge()+"岁");
//判断 是大象还是猴子
if(animals.get(i) instanceof Elephant){
Element weight = a.addElement("weight");
weight.setText(((Elephant) animals.get(i)).getWeight()+"吨");
}else {
Element height = a.addElement("height");
height.setText(((Monkey) animals.get(i)).getHeight()+"米");
}
}
//写入xml中
FileOutputStream out = new FileOutputStream("day23-java23/src/work/one/animal.xml");
OutputFormat format = OutputFormat.createPrettyPrint();
XMLWriter writer = new XMLWriter(out, format);
writer.write(doc);
writer.close();
}
}
总结
以上就是Xml文档相关方法和案例的全部内容，主要是Xml的内容增加以及查询方面的方法。