2021.3.22 JavaEE3 笔记 - 《Java学习笔记---武伟》

《学习内容》：

//========学习内容=========
原生DOM方式解析XML文件
JDOM和DOM4解析XML文件

《知识点—笔记》
//=========================

《代码内容》：
原生DOM解析XML文件

package parsexml;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.File;
import java.io.IOException;
@SuppressWarnings("all")
public class ParseXml {
    public static void main(String[] args) {
        try {
            //创建一个工厂 用来创建工人
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            //用工厂创建工人
            DocumentBuilder builder = factory.newDocumentBuilder();
            //给工人图纸  让他去读取xml文件然后调用方法拿到dom
            Document document = builder.parse(new File("src//testxml//test.xml"));
            //通过dom去获取和遍历整个xml文件
            //获取根标记
            Element school = document.getDocumentElement();
            String schoolID = school.getAttribute("id");
            String schoolName = school.getAttribute("name");
            String loc = school.getAttribute("loc");
            System.out.println(schoolID+"--"+schoolName+"--"+loc);
            //获取学校下面的班级
            NodeList classEleList = document.getElementsByTagName("class");
            for (int i = 0; i < classEleList.getLength(); i++) {
                //获取每个班级的属性
                Element classElem = (Element)classEleList.item(i);
                String classID = classElem.getAttribute("id");
                String className = classElem.getAttribute("name");
                String classLOC = classElem.getAttribute("loc");
                System.out.println("\t"+classID+"--"+className+"--"+classLOC);
                //获取班级下的 老师标签 属性
                NodeList teacherList = classElem.getElementsByTagName("teacher");
                for (int j = 0; j < teacherList.getLength(); j++) {
                    Element teacherEle = (Element)teacherList.item(j);
                    String teacherID = teacherEle.getAttribute("id");
                    String teacherName = teacherEle.getAttribute("name");
                    String sex = teacherEle.getElementsByTagName("sex").item(0).getTextContent();
                    System.out.println("\t \t"+teacherID+"--"+teacherName+"--"+sex);
                }
                //获取班级下 学生标签 属性
                NodeList studentList = classElem.getElementsByTagName("student");
                for (int j = 0; j < studentList.getLength(); j++) {
                    Element studentEle = (Element)studentList.item(j);
                    String studentID = studentEle.getAttribute("id");
                    String studentName = studentEle.getAttribute("name");
                    String sex = studentEle.getElementsByTagName("sex").item(0).getTextContent();
                    System.out.println("\t \t"+studentID+"--"+studentName+"--"+sex);
                }
            }
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

JDOM解析XML文件

package parsexml;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
import java.io.File;
import java.io.IOException;
import java.util.List;
public class JDom {
    public static void main(String[] args) {
        try {
            SAXBuilder saxBuilder = new SAXBuilder();
            Document document = saxBuilder.build(new File("src/testxml/test.xml"));
            //获取根标签
            Element school = document.getRootElement();
            //获取根标签的属性
            String schoolId = school.getAttributeValue("id");
            String schollName = school.getAttributeValue("name");
            String schoolLOC = school.getAttributeValue("loc");
            System.out.println(schoolId+"--"+schollName+"--"+schoolLOC);
            //通过school根标签去获取子标签
            List<Element> classList = school.getChildren("class");
            for (Element classEle : classList){
                String classID = classEle.getAttributeValue("id");
                String className = classEle.getAttributeValue("name");
                String clasLOC = classEle.getAttributeValue("loc");
                System.out.println("\t"+classID+"--"+className+"--"+clasLOC);
                //获取下面的老师和学生
                List<Element> teacher = classEle.getChildren("teacher");
                for (Element teacherEle : teacher){
                    String teacherID = teacherEle.getAttributeValue("id");
                    String teacherName = teacherEle.getAttributeValue("name");
                    String sex = teacherEle.getChildText("sex");
                    System.out.println("\t \t"+teacherID+"--"+teacherName+"--"+sex);
                }
                List<Element> studentList = classEle.getChildren("student");
                for (Element studentEle : studentList){
                    String studentID = studentEle.getAttributeValue("id");
                    String studentName = studentEle.getAttributeValue("name");
                    String studentSex = studentEle.getChildText("sex");
                    System.out.println("\t \t"+studentID+"--"+studentName+"--"+studentSex);
                }
            }
        } catch (JDOMException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

DOM4解析XML文**件**

package parsexml;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import java.io.File;
import java.util.List;
public class DOM4 {
    public static void main(String[] args) {
        try {
            SAXReader saxReader = new SAXReader();
            Document document = saxReader.read(new File("src/testxml/test.xml"));
            Element school = document.getRootElement();
            String schoolID = school.attributeValue("id");
            String schoolName = school.attributeValue("name");
            String schoolLOC = school.attributeValue("loc");
            System.out.println(schoolID+"--"+schoolName+"--"+schoolLOC);
            List<Element> classList = school.elements("class");
            for (Element classEle : classList){
                String classID = classEle.attributeValue("id");
                String className = classEle.attributeValue("name");
                String classLOC = classEle.attributeValue("loc");
                System.out.println("\t"+classID+"--"+className+"--"+classLOC);
                List<Element> teacherList = classEle.elements("teacher");
                for (Element teacherEle : teacherList){
                    String teacherID = teacherEle.attributeValue("id");
                    String teacherName = teacherEle.attributeValue("name");
                    String teacherSex = teacherEle.elementText("sex");
                    System.out.println("\t \t" + teacherID + "--"+ teacherName+"--"+teacherSex);
                }
                List<Element> studentList = classEle.elements("student");
                for (Element studentEle : studentList){
                    String studentID = studentEle.attributeValue("id");
                    String studentName = studentEle.attributeValue("name");
                    String studentSex = studentEle.elementText("sex");
                    System.out.println("\t \t"+studentID+"--"+studentName+"--"+studentSex);
                }
            }
        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }
}

学习总结：
学懂的：
没有什么不懂的，这个就是简单的写流程，但是DOM4的效率更高，他是基于JDOM又再次封装的，而JDOM是基于原生的DOM和
SEX封装的。
有问题的地方：
无
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