# parseXML

**Repository Path**: awgsyfy/parse-xml

## Basic Information

- **Project Name**: parseXML
- **Description**: Java解析XML文件的4种方法
- **Primary Language**: Java
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 3
- **Forks**: 0
- **Created**: 2020-12-29
- **Last Updated**: 2021-10-04

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Java解析XML文件的4种方法

> 参考: https://blog.csdn.net/m0_37499059/article/details/80505567

# 一、解析示例文件
`example.xml`
```xml
<?xml version="1.0" encoding="utf-8" ?>
<class>
    <student>
        <firstname>cxx1</firstname>
        <lastname>Bob1</lastname>
        <nickname>stars1</nickname>
        <marks>85</marks>
    </student>
    <student no="493">
        <firstname>cxx2</firstname>
        <lastname>Bob2</lastname>
        <nickname>stars2</nickname>
        <marks>85</marks>
    </student>
    <student no="593" status="1">
        <firstname>cxx3</firstname>
        <lastname>Bob3</lastname>
        <nickname>stars3</nickname>
        <marks>85</marks>
    </student>
</class>
```


# 二、DOM方式解析
- `pom.xml`
```xml
<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>top.syfy.xml</groupId>
    <artifactId>parse-xml</artifactId>
    <version>1.0-SNAPSHOT</version>
  </parent>

  <groupId>top.syfy.xml</groupId>
  <artifactId>parse-by-dom</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>parse-by-dom</name>
  <description>DOM方式解析XML文件</description>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <maven.compiler.target>1.8</maven.compiler.target>
    <maven.compiler.source>1.8</maven.compiler.source>
  </properties>
  
  <dependencies>
    <dependency>
      <groupId>org.w3c</groupId>
      <artifactId>dom</artifactId>
      <version>2.3.0-jaxb-1.0.6</version>
    </dependency>
  </dependencies>

</project>
```
- `ParseByDom.java`
```java
package top.syfy.xml;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
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;

/**
 * DOM方式解析XML文件
 *
 */
public class ParseByDom {

    /**
     * 使用Node的方式
     * @param nodes 节点列表
     */
    public static void node(NodeList nodes) {
        for (int i = 0; i < nodes.getLength(); i++) {
            Node node = nodes.item(i);
            NodeList childNodes = node.getChildNodes();
            for (int j = 0; j < childNodes.getLength(); j++) {
                Node childNode = childNodes.item(j);
                if (Node.ELEMENT_NODE == childNode.getNodeType()) {
                    // 获取节点
                    System.out.print(childNode.getNodeName() + " : ");
                    // 获取节点值
                    System.out.println(childNode.getFirstChild().getNodeValue());
                }
            }
        }
    }

    public static void main(String[] args) throws ParserConfigurationException, IOException, SAXException {
        // 创建DocumentBuilderFactory对象
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        // 创建DocumentBuilder对象
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document document = builder.parse(new File("example.xml"));
        NodeList studentList = document.getElementsByTagName("student");
        node(studentList);
    }
}
```
- 结果
```
firstname : cxx1
lastname : Bob1
nickname : stars1
marks : 85
firstname : cxx2
lastname : Bob2
nickname : stars2
marks : 85
firstname : cxx3
lastname : Bob3
nickname : stars3
marks : 85
```


# 三、SAX方式解析
- `pom.xml`
```xml
<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>top.syfy.xml</groupId>
    <artifactId>parse-xml</artifactId>
    <version>1.0-SNAPSHOT</version>
  </parent>

  <groupId>top.syfy.xml</groupId>
  <artifactId>parse-by-sax</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>parse-by-sax</name>
  <description>SAX方式解析XML文件</description>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <maven.compiler.target>1.8</maven.compiler.target>
    <maven.compiler.source>1.8</maven.compiler.source>
  </properties>

  <!-- sax解析XML文件使用的JDK自带的包,不需要引入依赖 -->
</project>
```
- `ParseBySax.java`
```java
package top.syfy.xml;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import java.io.File;
import java.io.IOException;

/**
 * SAX方式解析XML文件
 */
public class ParseBySax {
    public static void main(String[] args) throws IOException, SAXException, ParserConfigurationException {
        // 获取SaxParserFactory实例
        SAXParserFactory factory = SAXParserFactory.newInstance();
        // 获取SAXParser实例
        SAXParser saxParser = factory.newSAXParser();
        // 创建SAXHandler对象
        SAXHandler handler = new SAXHandler();
        saxParser.parse(new File("example.xml"), handler);
    }
}

/**
 * sax解析是从上到下依次解析, 如example.xml中的class -> student -> student -> ...
 */
class SAXHandler extends DefaultHandler {

    /**
     * 节点属性的索引
     */
    static int attributeIndex = 0;

    /**
     * XML文档遍历开始时的操作
     */
    @Override
    public void startDocument() throws SAXException {
        super.startDocument();
        System.out.println("=====sax文档解析开始=====\n\n");
    }

    /**
     * XML文档遍历结束时的操作
     */
    @Override
    public void endDocument() throws SAXException {
        super.endDocument();
        System.out.println("\n\n=====sax文档解析结束=====");
    }

    /**
     * 每个节点遍历开始时的操作
     */
    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        super.startElement(uri, localName, qName, attributes);
        if ("student".equals(qName)) {
            System.out.println("=====开始遍历student节点=====");
            /*
                遍历获取节点属性名称和属性值
                获取属性名称: getLocalName(int index) ==> 其中index为节点属性名称的索引值(从0开始)
                获取属性值: getValue(String attributeName) ==> 其中attributeName为节点属性名称
             */
            String attributeName;
            while ((attributeName = attributes.getLocalName(attributeIndex++)) != null) {
                System.out.println("属性: " + attributeName + "=" + attributes.getValue(attributeName));
            }
        } else if (!"class".equals(qName)) {
            System.out.print("节点名称: " + qName + "=");
        }
    }

    /**
     * 每个节点遍历结束时的操作
     */
    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        super.endElement(uri, localName, qName);
        if ("student".equals(qName)) {
            System.out.println("=====结束遍历student节点=====");
            attributeIndex = 0;
        }
    }

    /**
     * 返回的是节点的值
     */
    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        super.characters(ch, start, length);
        String value = new String(ch, start, length).trim();
        if (!"".equals(value)) {
            System.out.println(value);
        }
    }
}
```
- 结果
```
=====sax文档解析开始=====


=====开始遍历student节点=====
节点名称: firstname=cxx1
节点名称: lastname=Bob1
节点名称: nickname=stars1
节点名称: marks=85
=====结束遍历student节点=====
=====开始遍历student节点=====
属性: no=493
节点名称: firstname=cxx2
节点名称: lastname=Bob2
节点名称: nickname=stars2
节点名称: marks=85
=====结束遍历student节点=====
=====开始遍历student节点=====
属性: no=593
属性: status=1
节点名称: firstname=cxx3
节点名称: lastname=Bob3
节点名称: nickname=stars3
节点名称: marks=85
=====结束遍历student节点=====


=====sax文档解析结束=====
```


# 四、JDOM方式解析
- `pom.xml`
```xml
<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>top.syfy.xml</groupId>
    <artifactId>parse-xml</artifactId>
    <version>1.0-SNAPSHOT</version>
  </parent>

  <groupId>top.syfy.xml</groupId>
  <artifactId>parse-by-jdom</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>parse-by-jdom</name>
  <description>JDOM方式解析XML文件</description>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <maven.compiler.target>1.8</maven.compiler.target>
    <maven.compiler.source>1.8</maven.compiler.source>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.jdom</groupId>
      <artifactId>jdom</artifactId>
      <version>2.0.2</version>
    </dependency>
  </dependencies>


</project>
```
- `ParseByJdom.java`
```java
package top.syfy.xml;

import org.jdom2.Attribute;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 *
 * JDOM方式解析XML文件
 */
public class ParseByJdom {

    public static void main( String[] args ) throws IOException, JDOMException {
        // 创建SAXBuilder对象
        SAXBuilder builder = new SAXBuilder();
        // 创建输入流
        InputStream in = new FileInputStream(new File("example.xml"));
        // 将输入流加载到SAXBuilder中
        Document document = builder.build(in);
        // 获取根节点
        Element rootElement = document.getRootElement();
        // 获取子节点student
        List<Element> studentElementList = rootElement.getChildren();
        for (Element stuEle:studentElementList) {
            // 遍历student节点的属性
            List<Attribute> attributeList = stuEle.getAttributes();
            for (Attribute attribute:attributeList) {
                System.out.println("属性: " + attribute.getName() + "=" + attribute.getValue());
            }
            // 遍历student节点的子节点
            List<Element> studentSubElementList = stuEle.getChildren();
            for (Element sub:studentSubElementList) {
                System.out.println("节点: " + sub.getName() + "=" + sub.getValue());
            }
        }
    }
}
```
- 结果
```
节点: firstname=cxx1
节点: lastname=Bob1
节点: nickname=stars1
节点: marks=85
=========================
属性: no=493
节点: firstname=cxx2
节点: lastname=Bob2
节点: nickname=stars2
节点: marks=85
=========================
属性: no=593
属性: status=1
节点: firstname=cxx3
节点: lastname=Bob3
节点: nickname=stars3
节点: marks=85
=========================
```


# 五、DOM4J方式解析
- `pom.xml`
```xml
<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>top.syfy.xml</groupId>
    <artifactId>parse-xml</artifactId>
    <version>1.0-SNAPSHOT</version>
  </parent>

  <groupId>top.syfy.xml</groupId>
  <artifactId>parse-by-dom4j</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>parse-by-dom4j</name>
  <description>DOM4J方式解析XML文件</description>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <maven.compiler.target>1.8</maven.compiler.target>
    <maven.compiler.source>1.8</maven.compiler.source>
  </properties>

  <dependencies>
    <!-- dom4j  -->
    <dependency>
      <groupId>org.dom4j</groupId>
      <artifactId>dom4j</artifactId>
      <version>2.1.3</version>
    </dependency>
  </dependencies>

</project>
```
- `ParseByDom4j.java`
```java
package top.syfy.xml;

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

/**
 * DOM4j方式解析XML文件
 *
 */
public class ParseByDom4j {

    public static void main( String[] args ) throws DocumentException {
        // 创建Reader对象
        SAXReader reader = new SAXReader();
        // 创建输入流
        InputStream in = new FileInputStream(new File("example.xml"));
        // 加载XML文件
        Document document = reader.read(in);
        // 获取根节点
        Element rootElement = document.getRootElement();
        // 遍历节点
        Iterator<Element> iterator = rootElement.elementIterator();;
        while (iterator.hasNext()) {
            // 获取student节点
            Element studentElement = iterator.next();
            // 遍历student节点的属性
            List<Attribute> attributeList = studentElement.attributes();;
            for (Attribute attribute:attributeList) {
                System.out.println("属性: " + attribute.getName() + "=" + attribute.getValue());
            }
            // 获取student节点的子节点
            List<Element> studentSubElementList = studentElement.elements();;
            // 遍历student节点的子节点
            for (Element sub:studentSubElementList) {
                System.out.println("节点: " + sub.getName() + "=" + sub.getStringValue());
            }
            System.out.println("=========================");
        }

    }
}
```
- 结果
```
节点: firstname=cxx1
节点: lastname=Bob1
节点: nickname=stars1
节点: marks=85
=========================
属性: no=493
节点: firstname=cxx2
节点: lastname=Bob2
节点: nickname=stars2
节点: marks=85
=========================
属性: no=593
属性: status=1
节点: firstname=cxx3
节点: lastname=Bob3
节点: nickname=stars3
节点: marks=85
=========================
```


# 六、DOM-SAX-JDOM-DOM4J的比较
- DOM
    - 优点
        - 形成了树结构,直观好理解,代码更易编写
        - 解析过程中树结构保留在内存中,方便修改
    - 缺点
        - 当xml文件较大时,对内存耗费比较大,容易影响解析性能并造成内存溢出
- SAX
    - 优点
        - 采用事件驱动模式,对内存耗费比较小
        - 适用于只需要处理xm中数据时
    - 缺点
        - 不易编码
        - 很难同时访问同一个xml中的多处不同数据
- JDOM
    - 仅使用具体类而不使用接口
    - API大量使用了Collections类
- DOM4J
    - JDOM的一种智能分支,它合井了许多超出基本XML文档表示的功能
    - DOM4J使用接口和抽象基本类方法,是一个优秀的 Java XML API
    - 具有性能优异、灵活性好、功能强大和极端易用使用的特点
    - 是一个开放源代码的软件