?xml version="1.0" encoding="UTF-8"?>Students>
 student id="2">
  name>ttt/name>
  age>44/age>
 /student>
 student id="3">
  name>linda2/name>
  age>22/age>
 /student>
 student id="4">
  name>linda3/name>
  age>23/age>
 /student>
 student id="5">
  name>jack/name>
  age>2/age>
 /student>
 student id="1">
   name>yyh1/name>
   age>22/age>
 /student>
/Students>

import java.io.File;
import java.io.IOException;
import java.util.Scanner;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.SAXException;

//在學(xué)生管理系統(tǒng)里面，學(xué)生的學(xué)號(hào)是唯一的，姓名有可能重復(fù)
public class StudentManager {
  public static void main(String[] args) {
    try {
      Document doc = Domutils.getDoc(new File("xml文件的相對(duì)路徑"));
      Scanner input = new Scanner(System.in);
      System.out.println("歡迎來到學(xué)生管理系統(tǒng)\n\n\n請(qǐng)輸入你要進(jìn)行什么操作是：\n1.添加學(xué)生信息\n2.刪除學(xué)生信息\n3.修改學(xué)生信息\n(請(qǐng)輸入前邊的序號(hào))");
      int num = input.nextInt();
      if(num == 1) {
        addStudent(doc);
      }else if(num == 2) {
        delStudent(doc);
      }else if(num == 3) {
        updStudent(doc);
      }
    } catch (SAXException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } catch (ParserConfigurationException e) {
      e.printStackTrace();
    }
  }
  //修改學(xué)生信息
  private static void updStudent(Document doc) {
    Element updStudent = null;
    Scanner input = new Scanner(System.in);
    System.out.println("請(qǐng)輸入你要修改的學(xué)生的學(xué)號(hào)：");
    String studentid = input.nextLine();
    System.out.println("請(qǐng)輸入新學(xué)生的姓名：");
    String newName = input.nextLine();
    System.out.println("請(qǐng)輸入新學(xué)生的年齡：");
    String newAge = input.nextLine();
    
    //將每一個(gè)學(xué)生的列出來，for循環(huán)判斷你要修改信息的學(xué)生是哪一個(gè)
    NodeList list = doc.getElementsByTagName("student");
    for(int i = 0; i list.getLength(); i++) {
      if(studentid.equals(list.item(i).getAttributes().getNamedItem("id").getNodeValue())){
        updStudent = (Element) doc.getElementsByTagName("student").item(i).getFirstChild().getParentNode();
        //對(duì)學(xué)生的name屬性進(jìn)行賦新值
        updStudent.getElementsByTagName("name").item(i).getFirstChild().setNodeValue(newName);
        //對(duì)學(xué)生的age 屬性賦新值
        updStudent.getElementsByTagName("age").item(i).getFirstChild().setNodeValue(newAge);
        
      }else{
        break;
      }
    }
    //找出根元素，將修改后的元素持久化到文件
    Element root = doc.getDocumentElement();
    transform(root);
    System.out.println(updStudent);
  }
  //刪除學(xué)生信息
  private static void delStudent(Document doc) {
    Scanner input = new Scanner(System.in);
    //輸入你要?jiǎng)h除的學(xué)生的 學(xué)號(hào)
    System.out.println("請(qǐng)輸入要?jiǎng)h除學(xué)生的學(xué)號(hào)：");
    String studentid = input.nextLine();
    Element root = doc.getDocumentElement();
    
    //將學(xué)生列成一個(gè)表，進(jìn)行遍歷，找對(duì)應(yīng)學(xué)號(hào)的學(xué)生進(jìn)行刪除
    NodeList list = doc.getElementsByTagName("student");
    for(int i = 0; i  list.getLength(); i++) {
    if((studentid).equals(list.item(i).getAttributes().getNamedItem("id").getNodeValue())){
      Element delStudent = (Element) doc.getElementsByTagName("student").item(i).getFirstChild().getParentNode(); 
        root.removeChild(delStudent);
        break;
      }else {
        System.out.println("沒有該學(xué)生");
        break;
      }
    }
    //持久化到文件
    transform(root);
  }
  
  //添加學(xué)生信息
  private static void addStudent(Document doc) {
//    System.out.println(doc.getElementsByTagName("student").item(1).getAttributes().getNamedItem("id").getNodeValue());
    Element root = doc.getDocumentElement();
    //從控制臺(tái)輸入
    Scanner input = new Scanner(System.in);
    System.out.println("請(qǐng)輸入學(xué)生的序號(hào)：id = ");
     
    //將學(xué)生放到一個(gè)列表里面，看我們要添加的學(xué)生的學(xué)號(hào)里面是否已經(jīng)有了，如果有，需要將新加入的學(xué)生的學(xué)號(hào)改一下
    NodeList list = doc.getElementsByTagName("student");
    String studentid = input.nextLine();
    for(int i = 0; i  list.getLength(); i++) {
      if(studentid.equals(list.item(i).getAttributes().getNamedItem("id").getNodeValue())){
        System.out.println("該序號(hào)學(xué)生表里面已經(jīng)存在，請(qǐng)重新輸入一個(gè)新的序號(hào)：");
         studentid = input.nextLine();
      }else {
        break;
      }
    }
    
    System.out.println("請(qǐng)輸入要添加學(xué)生的姓名：name = ");
    String name_value = input.nextLine();
    System.out.println("請(qǐng)輸入要添加學(xué)生的年齡：age = ");
    String age_value = input.nextLine();
    
    //創(chuàng)建節(jié)點(diǎn)
    Element student = doc.createElement("student");
    Element name = doc.createElement("name");
    Element age = doc.createElement("age");
    Text namText = doc.createTextNode(name_value);
    Text ageText = doc.createTextNode(age_value);
    //關(guān)聯(lián)節(jié)點(diǎn)之間的關(guān)系
    root.appendChild(student);
    student.appendChild(name);
    student.appendChild(age);
    student.setAttribute("id", studentid);
    name.appendChild(namText);
    age.appendChild(ageText);
    //持久化到文件
    transform(root);
    
  }
  //持久化到文件的方法
  private static void transform(Element root)
      throws TransformerFactoryConfigurationError {
    TransformerFactory factory = TransformerFactory.newInstance();
    try {
      Transformer tf = factory.newTransformer();
      tf.transform(new DOMSource(root), new StreamResult(new File("src/com/briup/dom/student.xml")));
    } catch (TransformerConfigurationException e) {
      e.printStackTrace();
    } catch (TransformerException e) {
      e.printStackTrace();
    }
  }
}

import java.io.File;
import java.io.IOException;
import java.nio.file.attribute.AclEntry.Builder;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.xml.sax.SAXException;

public class Domutils {
  public static Document getDoc(File file) throws SAXException, IOException, ParserConfigurationException {
　　　　　　//獲取工廠模式
    DocumentBuilderFactory factory = 
        DocumentBuilderFactory.newInstance();
　　　　　　　　//獲取builder對(duì)象
      DocumentBuilder builder = factory.newDocumentBuilder();  
　　　　　　　　//將要解析文件加載成一個(gè)樹狀文件，開始解析     
      Document document = builder.parse(file);
    return document;
  }
}