使用Dom4J的CRUD操做

PS：最近在学习xml使用Dom4j的小练习总结CRUD操做

首先，XML的特点之一就是可以存储数据，所以在这里我把xml就当作是数据库来理解。

首先先创建一个Students的类用于查询遍历操作

Students类

package com.wei.dom4j;

public class Students {
  private String id;
  private String name;
  private int age;
  private String sex;

  public Students(String id, String name, int age, String sex) {
    super();
    this.id = id;
    this.name = name;
    this.age = age;
    this.sex = sex;
  }

  public Students() {
    super();
  }

  public String getId() {
    return id;
  }

  public void setId(String id) {
    this.id = id;
  }

  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;
  }

  public String getSex() {
    return sex;
  }

  public void setSex(String sex) {
    this.sex = sex;
  }

  @Override
  public String toString() {
    return "Students [id=" + id + ", name=" + name + ", age=" + age + ", sex=" + sex + "]";
  }
}

保存XML文件的类

package com.wei.dom4j;

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

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

public class SaveXML {
  public static void save(File file,Document document) {
    FileOutputStream fos = null;
    XMLWriter writer = null;
    try {
      // format.setIndentSize(2); // 行缩进
      // format.setNewlines(true); // 一个结点为一行
      // format.setTrimText(true); // 去重空格
      // format.setPadText(true);
      // format.setNewLineAfterDeclaration(false); // 放置xml文件中第二行为空白行

      fos = new FileOutputStream(file);
      OutputFormat format = OutputFormat.createPrettyPrint();
      format.setEncoding("UTF-8");
      writer = new XMLWriter(fos, format);
      writer.write(document);
      System.out.println("使用dom4j操做xml成功,请注意查验！");
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } finally { // 关闭流
      try {
        if (writer != null) {
          writer.close();
        }
      } catch (IOException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
      }
      try {
        if (fos != null) {
          fos.close();
        }
      } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
    }
  }
}

创建XML文件的类

package com.wei.dom4j;

import java.io.File;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;


/**
 * @版权 : Copyright (c) 2021-2025 鼎立公司技术开发部
 * @author: WYP
 * @版本: 1.0
 * @创建日期: 2022年1月14日 上午9:21:44
 * @ClassName CreateXML
 * @类描述-Description: TODO(这里用一句话描述这个方法的作用)
 */
public class CreateXML {
  public static void main(String[] args) {
    //测试
    create(new File("resources/dom4jCreate.xml"));
  }

  public static void create(File file) {
    Document document = DocumentHelper.createDocument();
    // 创建根
    Element root = document.addElement("Students");
    root.addAttribute("info", "学生信息");
    // 第一个节点
    Element student1 = root.addElement("student");
    student1.addAttribute("id", "s001");
    Element name1 = student1.addElement("name");
    name1.addText("张三");
    Element age1 = student1.addElement("age");
    age1.addText("23");
    Element sex1 = student1.addElement("sex");
    sex1.addText("男");
    // 第二个节点
    Element student2 = root.addElement("student");
    student2.addAttribute("id", "s002");
    Element name2 = student2.addElement("name");
    name2.addText("李四");
    Element age2 = student2.addElement("age");
    age2.addText("21");
    Element sex2 = student2.addElement("sex");
    sex2.addText("女");
    //保存调用方法
    SaveXML.save(file, document);
  }
}

添加节点操做的类

package com.wei.dom4j;

import java.io.File;

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

public class AddXML {
  public static void main(String[] args) {
    add(new File("resources/dom4jCreate.xml"));
  }

  public static void add(File file) {
    SAXReader reader = new SAXReader();
    try {
      Document document = reader.read(file);
      Element root = document.getRootElement();
      Element student3 = root.addElement("student");
      student3.addAttribute("id", "s003");
      Element name3 = student3.addElement("name");
      name3.setText("张老刘");
      Element age3 = student3.addElement("age");
      age3.setText("25");
      Element sex3 = student3.addElement("sex");
      sex3.setText("男");

      SaveXML.save(file, document);
      System.out.println("使用dom4j添加xml节点成功,请注意查验！");
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
}

删除节点操作的类

package com.wei.dom4j;

import java.io.File;

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

public class DeleteXML {

  public static void main(String[] args) {
    delete(new File("resources/dom4jCreate.xml"), "s003");
  }

  public static void delete(File file, String targetId) {
    try {
      SAXReader reader = new SAXReader();
      Document document = reader.read(file);
      Element root = document.getRootElement();
      // id类型的id这样查找
      // document.selectSingleNode("Students/student[@id='1003']");
      // String类型的id这样查找
      Node node = document.selectSingleNode("Students/student[@id='" + targetId + "']");
      if (node != null) {
        Element ele = (Element) node;
        root.remove(ele);
      } else {
        System.out.println("查无此人！");
      }
      SaveXML.save(file, document);
      System.out.println("删除成功！");
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
}

修改节点操作的类

package com.wei.dom4j;

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

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

public class UpdateXML {
  public static void main(String[] args) {
    updateName(new File("resources/dom4jCreate.xml"), "s002","李老头");
  }
  
  public static void updateName(File file,String targetId,String updateName) {
    SAXReader reader = new SAXReader();
    try {
      Document document = reader.read(file);
      Element root = document.getRootElement();
  
      List<Element> namelist = root.elements("student");
      for (Element element : namelist) {
        Attribute attr = element.attribute("id");
        if (attr.getText().equals(targetId)) {
          element.element("name").setText(updateName);
        }
      }
      SaveXML.save(file, document);
      System.out.println("修改成功！请注意查验！");
    } catch (Exception e) {
      System.err.println("修改失败！");
    }
  }
}

查询操做的类

package com.wei.dom4j;

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

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

public class SelectXML {
  public static void main(String[] args) {
    selectByName(new File("resources/dom4jCreate.xml"));
    selectByFirstName(new File("resources/dom4jCreate.xml"));
    findAll(new File("resources/dom4jCreate.xml"));
  }

  /**
   * 
   * @Title: selectByName
   * @Description:根据名字查询
   * @return void  返回类型
   */
  public static void selectByName(File file) {
    SAXReader reader = new SAXReader();
    try {
      Document document = reader.read(file);
      Node node = document.selectSingleNode("Students/student[name='张三']");
      if (node != null) {
        Element e = (Element) node;
        System.out.println(e.attributeValue("id"));
        System.out.println(e.elementText("name"));
        System.out.println(e.elementText("age"));
        System.out.println(e.elementText("sex"));
      } else {
        System.out.println("查无此人");
      }
    } catch (DocumentException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }

  /**
   * 
   * @Title: selectByFirstName
   * @Description: 根据名字模糊查询
   * @return void  返回类型
   */
  public static void selectByFirstName(File file) {
    SAXReader reader = new SAXReader();
    try {
      Document document = reader.read(file);
      List<Element> list = document.selectNodes("Students/student[contains(name,'张')]");
      if (list.size() > 0) {
        for (Element element : list) {
          System.out.println(element.attributeValue("id"));
          System.out.println(element.elementText("name"));
          System.out.println(element.elementText("age"));
          System.out.println(element.elementText("sex"));
        }
      }
    } catch (DocumentException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }

  /**
   * 
   * @Title: findAll
   * @Description: 查询所有的方法
   * @return void  返回类型
   */
  public static void findAll(File file) {
    SAXReader reader = new SAXReader();
    List<Students> Studntlist = new ArrayList<Students>();
    try {
      Document document = reader.read(file);
      Element rootElement = document.getRootElement();
      List<Node> list = rootElement.elements();
      if (list.size() > 0) {
        for (Node node : list) {
          Element e = (Element) node;
          String id = e.attributeValue("id");
          String name = e.elementText("name");
          String age = e.elementText("age");
          String sex = e.elementText("sex");
          
          Students students  = new Students(id,name,Integer.parseInt(age),sex);
          Studntlist.add(students);
        }
      }
      
      for(int i = 0;i<Studntlist.size();i++) {
        System.out.println(Studntlist.get(i));
      }
        
    } catch (DocumentException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
}

创建XML运行结果

<?xml version="1.0" encoding="UTF-8"?>

<Students info="学生信息"> 
  <student id="s001"> 
    <name>张三</name>  
    <age>23</age>  
    <sex>男</sex> 
  </student>  
  <student id="s002"> 
    <name>李四</name>  
    <age>21</age>  
    <sex>女</sex> 
  </student>  
</Students>

增加节点操做结果

<?xml version="1.0" encoding="UTF-8"?>

<Students info="学生信息"> 
  <student id="s001"> 
    <name>张三</name>  
    <age>23</age>  
    <sex>男</sex> 
  </student>  
  <student id="s002"> 
    <name>李四</name>  
    <age>21</age>  
    <sex>女</sex> 
  </student>  
  <student id="s003">
    <name>张老刘</name>
    <age>25</age>
    <sex>男</sex>
  </student>
</Students>

修改XML文件结果

<?xml version="1.0" encoding="UTF-8"?>

<Students info="学生信息"> 
  <student id="s001"> 
    <name>张三</name>  
    <age>23</age>  
    <sex>男</sex> 
  </student>  
  <student id="s002"> 
    <name>李老头</name>  
    <age>21</age>  
    <sex>女</sex> 
  </student>  
  <student id="s003"> 
    <name>张老刘</name>  
    <age>25</age>  
    <sex>男</sex> 
  </student> 
</Students>

查询操作结果