Dom4j的使用

作者: A_一只小菜鸟 | 来源:发表于2020-08-17 17:25 被阅读0次

dom4j是一个Java的XML API，是jdom的升级品，用来读写XML文件的。dom4j是一个十分优秀的javaXML API，具有性能优异、功能强大和极其易使用的特点，它的性能超过sun公司官方的dom技术，同时它也是一个开放源代码的软件，可以在SourceForge上找到它。

一、dom4j介绍

使用方式：在pom.xml中导入dom4j对应的jar

<dependency>
    <groupId>dom4j</groupId>
    <artifactId>dom4j</artifactId>
    <version>1.6.1</version>
</dependency>

优点：dom4j使Java生成和解析XML灵活性变高，并且代码易于维护。

API操作类：
Document：表示xml文档信息，是一个树形结构
Eelment：表示xml的元素结点，提供一些操作其子元素方法的，如文本、属性、名称空间等
Attribute：表示元素结点中的属性

二、常用API

1.创建Document 和Element对象：

Document doc=DocumentHelper.createDocument();
Element eltRoot=DocumentHelper.createElement("student");
doc.setRootElement(eltRoot);

2.或者先准备好根元素，使用有参数的构造方法创建Document对象。

Element eltRoot=DocumentHelper.createElement(“student”);
Document doc=DocumentHelper.createDocument(eltRoot);

3.添加节点和设置节点内容

Element eltName=eltRoot.addElement(“name”);
Element eltAge=eltRoot.addElement(“age”);
eltName.setText(“张三”);
eltAge.setText(“18”);

4.添加属性

eltRoot.addAttribute(“sn”,”01”);

5.使用 SAXReader 构建dom4j文档对象

SAXReader saxReader=new SAXReader();
File file=new File(“student.xml”);
Document doc=saxReader.read(file);

6.使用DOMReader 构建dom4j 文档对象

DocumentBuilderFactory dbf=new DocumentBuilderFactory.newInstance();
DocumentBuilder db=dbf.newDocumentBuilder();
File file=new File(“student.xml”);
org.w3c.dom.Document document=db.parse(file);
DOMReader domReader=new DOMReader();
org.dom4j.Document doc=domReader.read(document);

7.访问根节点：

Element root=doc.getRootElement();

8.访问所有节点:

java.util.List childrenList=elt.elements();

9.访问指定名称的所有节点

java.util.Liat childrenList=elt.elements(“student”);

10.访问指定名称第一个节点

Element eltChild=elt.element(“student”);

11.要迭代某个元素的所有子元素

for(java.util.Iterator it=root.elementIterator();it.hasNext()){
Element element =it.hasNext();
……
}

输出文档：
对象：XMLWriter 实例方法：write（Document doc）
常用的几种构造方法总结：
1：无参数：
2:字节流参数
3：字符流参数。
4：文档输出格式类参数。
示例代码1：
输出文档内容到控制台

XMLWriter xw=new XMLWriter();
xw.write(doc);

三、dom4j 生成 xml

实现步骤：

第一步：创建一个Document实例
Document doc = DocumentHelper.createDocument();

第二步：先添加一个根结点，然后再添加子结点，构造成一个树形结构
Element root = doc.addElement("root");

第三步：添加xml文件样式（也可自定义样式），并输出xml文件到指定的路径下
OutputFormat format = OutputFormat.createPrettyPrint();
XMLWriter writer = new XMLWriter(new FileOutputStream(file), format);
writer.write(doc);
实现源码

package com.oysept.xml;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import org.jdom2.output.Format;

/**
 * dom4j生成xml
 * @author ouyangjun
 */

public class CreateDom4j {

    public static void main(String[] args) {
        // 执行dom4j生成xml方法
        createDom4j(new File("E:\\dom4j.xml"));
    }

    public static void createDom4j(File file) {
        try {
            // 创建一个Document实例
            Document doc = DocumentHelper.createDocument();
            // 添加根节点
            Element root = doc.addElement("root");
            // 在根节点下添加第一个子节点
            Element oneChildElement= root.addElement("person").addAttribute("attr", "root noe");

            oneChildElement.addElement("people").addAttribute("attr", "child one").addText("person one child one");

            oneChildElement.addElement("people") .addAttribute("attr", "child two") .addText("person one child two");

            // 在根节点下添加第一个子节点

            Element twoChildElement= root.addElement("person").addAttribute("attr", "root two");

            twoChildElement.addElement("people") .addAttribute("attr", "child one").addText("person two child one");
            twoChildElement.addElement("people") .addAttribute("attr", "child two").addText("person two child two");

            // xml格式化样式
            // OutputFormat format = OutputFormat.createPrettyPrint(); // 默认样式

            // 自定义xml样式
            OutputFormat format = new OutputFormat();
            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

            // 输出xml文件
            XMLWriter writer = new XMLWriter(new FileOutputStream(file), format);
            writer.write(doc);
            System.out.println("dom4j CreateDom4j success!");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

XML文件效果图：

untitled.png

四、dom4j解析xml

实现步骤

第一步：创建一个SAXReader解析器
SAXReader reader = new SAXReader();

第二步：解析xml文件，重新构建成一个Document对象
Document doc = reader.read(file);

第三步：处理Document对象信息，在控制台打印

实现源码：

package com.oysept.xml; 

import java.io.File;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Attribute;
import org.dom4j.CDATA;
import org.dom4j.Comment;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.Text;
import org.dom4j.io.SAXReader;

/**
 * dom4j解析xml
 * @author ouyangjun
 */

public class ParseDom4j {

    public static void main(String[] args) {
        // 执行dom4j解析xml方法
        parseDom4j(new File("E:\\dom4j.xml"));
    }

    public static void parseDom4j(File file) {
        try {
            // 创建一个SAXReader解析器
            SAXReader reader = new SAXReader();
            // 读取xml文件,转换成Document结点
            Document doc = reader.read(file);
            // 递归打印xml文档信息
            StringBuffer buffer = new StringBuffer();
            parseElement(doc.getRootElement(), buffer);
            System.out.println(buffer.toString());
        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }

    @SuppressWarnings("unchecked")
    public static void parseElement(Element element, StringBuffer buffer) {
        buffer.append("<"+element.getName());
        List<Attribute> attrs = element.attributes();
        if (attrs != null) {
            for (Attribute attr : attrs) {
                buffer.append(" "+attr.getName()+"=\""+attr.getValue()+"\"");
            }
        }
        buffer.append(">");
        Iterator<Node> iterator = element.nodeIterator();
        while (iterator.hasNext()) {
            Node node = iterator.next();
            if (node instanceof Element) {
                Element eleNode = (Element) node;
                parseElement(eleNode, buffer);
            }
            if (node instanceof Text) {
                Text text = (Text) node;
                buffer.append(text.getText());
            }

            if (node instanceof CDATA) {
                CDATA dataNode = (CDATA) node;
                buffer.append(dataNode.getText());
            }

            if (node instanceof Comment) {
                Comment comNode = (Comment) node;
                buffer.append(comNode.getText());
            }
        }
        buffer.append("</"+element.getName()+">");
    }
}

XML文件解析效果图打印：

untitled.png

五、dom4j解析生成字符串

import java.io.IOException;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;

/**
 *
 * @author y
 */
public class Test {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws DocumentException {
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("name", "李四");
        map.put("age", 25);
        
        //System.out.println(map2xml(map));
        
        
        List<Object> list = new ArrayList<Object>();
        list.add("测试1");
        list.add("测试2");
        list.add("测试3");
        
        //System.out.println(list2xml(list,"items"));
        
        List<Map<String,Object>> listMap = new ArrayList<Map<String,Object>>();
        Map<String,Object> map1 = new HashMap<String,Object>();
        map1.put("name", "张三");
        map1.put("age", 23);
        listMap.add(map1);
        map1 = new HashMap<String,Object>();
        map1.put("name", "李四");
        map1.put("age", 24);
        listMap.add(map1);
        map1 = new HashMap<String,Object>();
        map1.put("name", "王五");
        map1.put("age", 25);
        listMap.add(map1);
        
        System.out.println(listMap2xml(listMap,"users","user"));
        
    }
    
    
    public static String listMap2xml(List<Map<String,Object>> list,String listRoot,String mapRoot){
        Document doc = DocumentHelper.createDocument();
        
        Element rootEle = doc.addElement("result");
        Element noEle = rootEle.addElement("no");
        Element msgEle = rootEle.addElement("msg");
        
        if(null!=list && !list.isEmpty()){
            noEle.setText("1");
            msgEle.setText("成功获取相关信息");
            
            Element listRootEle = rootEle.addElement(listRoot);
            
            for(Map<String,Object> map:list){
                
                Element mapRootELe = listRootEle.addElement(mapRoot);
                
                Set<Map.Entry<String,Object>> set = map.entrySet();
                Iterator<Map.Entry<String,Object>> iter = set.iterator();
                while(iter.hasNext()){
                    Map.Entry<String,Object> entry = (Map.Entry<String,Object>)iter.next();
                    
                    Element ele = mapRootELe.addElement(entry.getKey());
                    ele.setText(String.valueOf(entry.getValue()));
                }
            }
        }else{
            noEle.setText("0");
            msgEle.setText("没有获取到相关信息");
        }
        
        StringWriter sw = new StringWriter();
        OutputFormat format = OutputFormat.createPrettyPrint();
        format.setEncoding("utf-8");
        
        try {
            
            XMLWriter xmlWriter = new XMLWriter(sw, format);
            
            xmlWriter.write(doc);
        } catch (IOException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        }finally{
            try {
                sw.close();
            } catch (IOException ex) {
                Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

        return sw.toString();
    }

    
    public static String list2xml(List<Object> list,String itemRoot){
        Document doc = DocumentHelper.createDocument();
        
        Element rootEle = doc.addElement("result");
        Element noEle = rootEle.addElement("no");
        Element msgEle = rootEle.addElement("msg");
        
        if(null!=list && !list.isEmpty()){
            noEle.setText("1");
            msgEle.setText("成功获取相关信息");
            
            Element itemRootEle = rootEle.addElement(itemRoot);
            
            for(Object obj:list){
                Element ele = itemRootEle.addElement("item");
                ele.setText(String.valueOf(obj));
            }
        }else{
            noEle.setText("0");
            msgEle.setText("没有获取到相关信息");
        }
        
        StringWriter sw = new StringWriter();
        OutputFormat format = OutputFormat.createPrettyPrint();
        format.setEncoding("utf-8");
        
        try {
            
            XMLWriter xmlWriter = new XMLWriter(sw, format);
            
            xmlWriter.write(doc);
        } catch (IOException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        }finally{
            try {
                sw.close();
            } catch (IOException ex) {
                Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

        return sw.toString();
    }
    
    public static String map2xml(Map<String, Object> map) {
        Document doc = DocumentHelper.createDocument();
        
        Element rootEle = doc.addElement("result");
        
        Element noEle = rootEle.addElement("no");
        Element msgEle = rootEle.addElement("msg");
        
        if(null!=map && !map.isEmpty()){
            noEle.setText("1");
            msgEle.setText("成功获取相关信息");
            
            Set<Map.Entry<String, Object>> set = map.entrySet();
            Iterator<Map.Entry<String, Object>> iter = set.iterator();
            while(iter.hasNext()){
                Map.Entry<String, Object> entry = (Map.Entry<String, Object>) iter.next();
                
                Element ele = rootEle.addElement(entry.getKey());
                ele.setText(String.valueOf(entry.getValue()));
            }
        }else{
            noEle.setText("0");
            msgEle.setText("没有获取到相关信息");
        }
        
        StringWriter sw = new StringWriter();
        OutputFormat format = OutputFormat.createPrettyPrint();
        format.setEncoding("utf-8");
        
        try {
            
            XMLWriter xmlWriter = new XMLWriter(sw, format);
            
            xmlWriter.write(doc);
        } catch (IOException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        }finally{
            try {
                sw.close();
            } catch (IOException ex) {
                Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

        return sw.toString();
    }
    
    

    public static void test4() {
        Document doc = DocumentHelper.createDocument();

        Element rootEle = doc.addElement("sudent");

        Element nameEle = rootEle.addElement("name");
        nameEle.setText("张三");

        Element ageEle = rootEle.addElement("age");
        ageEle.setText("25");

        try {
            StringWriter sw = new StringWriter();
            OutputFormat format = OutputFormat.createPrettyPrint();
            format.setEncoding("utf-8");
            XMLWriter xmlWriter = new XMLWriter(sw, format);

            xmlWriter.write(doc);

            System.out.println(sw.toString());
        } catch (IOException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

    public static void test3() throws DocumentException {
        String str = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
                + "<books>"
                + "    <book>"
                + "        <name>Think in Java</name>"
                + "        <price>120.0</price>"
                + "           <chapters>"
                + "               <c>001</c>"
                + "               <c>002</c>"
                + "               <c>003</c>"
                + "           </chapters>"
                + "    </book>"
                + "    <book>"
                + "        <name>Think in Java2</name>"
                + "        <price>220.0</price>"
                + "    </book>"
                + "</books>";
        Document doc = DocumentHelper.parseText(str);
        Element books = doc.getRootElement();
        List<Element> childEles = books.elements();
        Iterator<Element> iter = childEles.iterator();
        while (iter.hasNext()) {
            Element book = iter.next();

            Element name = book.element("name");
            Element price = book.element("price");

            System.out.println("name:" + name.getText() + ",price:" + price.getText());

            Element chapters = book.element("chapters");
            if (null != chapters) {
                Iterator<Element> chaptersIter = chapters.elementIterator();
                if (null != chaptersIter) {
                    while (chaptersIter.hasNext()) {
                        Element c = chaptersIter.next();
                        System.out.println("===>" + c.getText());
                    }
                }
            }

        }
    }

    public static void test2() throws DocumentException {
        String str = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
                + "<books>"
                + "    <book>"
                + "        <name>Think in Java</name>"
                + "        <price>120.0</price>"
                + "    </book>"
                + "    <book>"
                + "        <name>Think in Java2</name>"
                + "        <price>220.0</price>"
                + "    </book>"
                + "</books>";

        Document doc = DocumentHelper.parseText(str);

        Element books = doc.getRootElement();

        List<Element> childEles = books.elements();
        Iterator<Element> iter = childEles.iterator();
        while (iter.hasNext()) {
            Element book = iter.next();

            Element name = book.element("name");
            Element price = book.element("price");

            System.out.println("name:" + name.getText() + ",price:" + price.getText());
        }
    }

    public static void test1() throws DocumentException {
        String str = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
                + "<dzswdjz>"
                + "    <qr_code>"
                + "　　　<nsrsbh>nsrsbh</nsrsbh >"
                + "　　　<retStatus >retStatus</retStatus>"
                + "　　　<img_name>img_name</img_name>"
                + "      <img_byteString>img_byteString</img_byteString>"
                + "   </qr_code>"
                + "</dzswdjz>";
        Document doc = DocumentHelper.parseText(str);

        //获取到父节点
        Element dzswdjz = doc.getRootElement();

        //定位到qr_code节点
        Element qr_code = dzswdjz.element("qr_code");

        Element nsrsbh = qr_code.element("nsrsbh");
        Element retStatus = qr_code.element("retStatus");
        Element img_name = qr_code.element("img_name");
        Element img_byteString = qr_code.element("img_byteString");

        System.out.println("nsrsbh:" + nsrsbh.getText());
        System.out.println("retStatus:" + retStatus.getText());
        System.out.println("img_name:" + img_name.getText());
        System.out.println("img_byteString:" + img_byteString.getText());
    }
}

Dom4j的使用

一、dom4j介绍

二、常用API

三、dom4j 生成 xml

四、dom4j解析xml

五、dom4j解析生成字符串

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