如何使用apache commons解析xml中的配置文件？

Question

我使用apache commons配置1.10来管理xml配置。这是xml格式的配置文件。

<?xml version="1.0" encoding="ISO-8859-1" ?> 
<config> 
    <mainServerHostname>MainServer</mainServerHostname> 
    <failoverServers> 
     <server> 
      <ipAddress>192.168.0.5</ipAddress> 
      <priority>1</priority> 
     </server> 
     <server> 
      <ipAddress>192.168.0.6</ipAddress> 
      <priority>2</priority> 
     </server> 
    </failoverServers> 
</config> 

我需要打印以下

mainServerHostname=MainServer 
failoverServers.server.ipAddress=192.168.0.5 
failoverServers.server.priority=1 
failoverServers.server.ipAddress=192.168.0.6 
failoverServers.server.ipAddress=2 

这是代码片段我写

public void loadXmlFile(String filename) { 
    XMLConfiguration config = null; 
    try { 
     config = new XMLConfiguration(filename); 
    } catch (ConfigurationException e) { 
     e.printStackTrace(); 
    } 
    List<HierarchicalConfiguration> fields= config. configurationsAt("failoverServers"); 
    for (Iterator it = fields.iterator(); it.hasNext();) { 
     HierarchicalConfiguration sub = (HierarchicalConfiguration) it 
       .next(); 
     Iterator<String> keyIter = sub.getKeys(); 
     String key, value; 
     while (keyIter.hasNext()) { 
      key = keyIter.next(); 
      value = sub.getString(key); 
      System.out.println("Key:: " + key + " Val:: " + value); 
     } 
    } 

} 

这是运行在上面的代码之后的结果。因为，我无法遍历整个xml树结构。

Key:: server.ipAddress Val:: 192.168.0.5 
Key:: server.priority Val:: 1 

任何人都可以请帮助我如何获得所需的输出？

Answer 1

如果你有讲究阿帕奇百科全书的配置，你可以不喜欢

public void loadXmlFile(String filename) { 
    XMLConfiguration config = null; 
    try { 
     config = new XMLConfiguration(filename); 
    } catch (ConfigurationException e) { 
     e.printStackTrace(); 
    } 
    Iterator<String> keyIter = config.getKeys(); 
    String key; 
    while (keyIter.hasNext()) { 
     key = keyIter.next(); 
     Object prop = config.getProperty(key); 
     if(prop instanceof Collection) { 
       List<String> values = (List<String>) prop; 
       for(String value : values){ 
        System.out.println(key + "=" + value); 
       } 
     } else { 
      System.out.println(key + "=" + prop); 
     } 
    } 
} 

对于上面的XML，这将打印

mainServerHostname=MainServer 
failoverServers.server.ipAddress=192.168.0.5 
failoverServers.server.ipAddress=192.168.0.6 
failoverServers.server.priority=1 
failoverServers.server.priority=2 

或者你可以使用一个StAX的解析器和实现这一目标。

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

import javax.xml.stream.XMLInputFactory; 
import javax.xml.stream.XMLStreamConstants; 
import javax.xml.stream.XMLStreamReader; 

import org.apache.commons.lang3.StringUtils; 


public class ConfigParser { 

    public static void main(String[] args) throws Exception { 
     StringBuilder content = null; 
     List<String> parents = new ArrayList<>(); 
     XMLInputFactory factory = XMLInputFactory.newInstance(); 
     XMLStreamReader reader = 
     factory.createXMLStreamReader(new FileInputStream("prop.xml")); 

     while(reader.hasNext()){ 
      int event = reader.next(); 

      switch(event){ 
     case XMLStreamConstants.START_ELEMENT: 
      content = new StringBuilder(); 
      if(!"config".equalsIgnoreCase(reader.getLocalName())) { 
       parents.add(reader.getLocalName()); 
      } 
      break; 

     case XMLStreamConstants.CHARACTERS: 
      if (content != null) { 
        content.append(reader.getText().trim()); 
       } 
      break; 

     case XMLStreamConstants.END_ELEMENT: 
      if (content != null) { 
        System.out.println(StringUtils.join(parents, '.') + "=" + content.toString()); 
       } 
      parents.remove(reader.getLocalName()); 
       content = null; 
       break; 

     case XMLStreamConstants.START_DOCUMENT: 
      break; 
      } 

     } 
    } 

}