DOM4J parses XML files with XPath

DOM4J is an open source XML parsing package, which is used by many frameworks to parse XML files, such as Mybatis and Spring framework.

Here are the basic uses:

Introduction of depend on

  <! - dom4j dependence - >
  <dependency>
    <groupId>dom4j</groupId>
    <artifactId>dom4j</artifactId>
    <version>1.6.1</version>
  </dependency>
  <! -- Xpath expression dependencies -->
  <dependency>
    <groupId>jaxen</groupId>
    <artifactId>jaxen</artifactId>
    <version>1.1.6</version>
  </dependency>
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Prepare an XML fileapplicationConfig.xml

      

<configuration>
    <! -- Database configuration information -->
    <dataSource>
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/spring"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </dataSource>
</configuration>
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To parse the XML

public Document parse(a) throws DocumentException {
    // Load the configuration file into memory through the class loader
    InputStream inputStream = XmlConfigBuilder.class.getClassLoader().getResourceAsStream("applicationConfig.xml");
    // Parse the XML file
    SAXReader reader = new SAXReader();
    Document document = reader.read(inputStream);
    return document;
}
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Gets the document root node

Element rootElement = document.getRootElement();
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Navigate to specific labels using XPath

XPath is a language for finding information in XML documents. XPath can be used to traverse elements and attributes in AN XML document.

// Read the property tag
List propertyList = rootElement.selectNodes("//property");
Properties properties = new Properties();
for (Object o : propertyList) {
    Element element = (Element)o;
    // Get tag attributes
    String value = element.attributeValue("value");
    String name = element.attributeValue("name");
    properties.setProperty(name,value);
}
// Convert the property tag content to the DruidDataSource object
DruidDataSource druidDataSource = new DruidDataSource();
druidDataSource.setDriverClassName(properties.getProperty("driverClass"));
druidDataSource.setUrl(properties.getProperty("jdbcUrl"));
druidDataSource.setUsername(properties.getProperty("username"));
druidDataSource.setPassword(properties.getProperty("password"));
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