解析XML内容到User对象

users.xml

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

 <xml-root>
     <conn-params>
         <conn-url>jdbc:mysql://192.168.101.7:3306/bbs</conn-url>
         <conn-driver>com.mysql.jdbc.Driver</conn-driver>
         <conn-username>root</conn-username>
         <conn-password>root</conn-password>
     </conn-params>

     <person xmlns:u="http://example.org/user">
         <u:user>
             <u:username>xzc</u:username>
             <u:password>sdf23223</u:password>
             <u:birthday>2012-01-23</u:birthday>
         </u:user>
         <u:user>
             <u:username>误闯</u:username>
             <u:password>wuchuang3223</u:password>
             <u:birthday>2002-01-03</u:birthday>
         </u:user>
     </person>
 </xml-root>

采用DOM api 解析XML

1. User类

 public class User {

     private String username;
     private String password;
     private String birthday;

     public String toString() {
         return "username = " + username + ", password = " + password + ", birthday = " + birthday;
     }

　　　　//省略setter,getter
 }

2. DomUtil解析类

 package sax.parsing.user;

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

 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.ParserConfigurationException;

 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 import org.xml.sax.InputSource;

 public class DomUtil {

     private DocumentBuilderFactory builderFactory;
     private DocumentBuilder builder;
     private Document document;

     public DomUtil() throws ParserConfigurationException {
         builderFactory = DocumentBuilderFactory.newInstance();
         builder = builderFactory.newDocumentBuilder();
     }

     public DocumentBuilderFactory getBuilderFactory() {
         return builderFactory;
     }
     public DocumentBuilder getBuilder() {
         return builder;
     }

     public List<User> parseXml(String filepath) throws Exception {

         document = builder.parse(new InputSource(new FileInputStream(filepath)));

         List<User> list = new ArrayList<User>();

         Element root = document.getDocumentElement(); //从文档根节点获取文档根元素节点root => xml
         NodeList childNodes = root.getChildNodes();

         for (int i=0; i<childNodes.getLength(); i++) {
             Node node = childNodes.item(i);

             /*
              *     <person>
                         <user>
                             <username>xzc</username>
                             <password>sdf23223</password>
                             <birthday>2012-01-23</birthday>
                         </user>
                         <user>
                             <username>误闯</username>
                             <password>wuchuang3223</password>
                             <birthday>2002-01-03</birthday>
                         </user>
                     </person>
              */
             if ("person".equals(node.getNodeName())) {

                 NodeList pChildNodes = node.getChildNodes();

                 for (int t=0; t<pChildNodes.getLength(); t++) {

                     Node nd = pChildNodes.item(t);

                     if (nd.getNodeType() == Node.ELEMENT_NODE && nd.getNodeName().equals("user")) {

                         User user = new User();

                         NodeList userChildNodes = nd.getChildNodes();

                         for (int k=0; k<userChildNodes.getLength(); k++) {
                             Node userNode = userChildNodes.item(k);
                             String nodeName = userNode.getNodeName();
                             String nodeValue = userNode.getTextContent();
                             System.out.println("nodeType=" + userNode.getNodeType() + ", nodeName=" + nodeName + ", nodeValue=" + nodeValue);

                             if ("username".equals(nodeName))
                                 user.setUsername(nodeValue);
                             if ("password".equals(nodeName))
                                 user.setPassword(nodeValue);
                             if ("birthday".equals(nodeName))
                                 user.setBirthday(nodeValue);
                         }
                         list.add(user);
                     } // 若当前节点是user
                 }
             } // 若当前元素是person的处理逻辑
         }// 完成对根元素的所有子节点的判断

         return list;
     }

     public static void main(String[] args) {

         try {
             DomUtil domUtil = new DomUtil();
             List<User> users = domUtil.parseXml("src/sax/parsing/user/jdbc-params.xml");

             for(User user : users) {
                 System.out.println(user);
             }
         } catch (ParserConfigurationException e) {
             e.printStackTrace();
         } catch (Exception e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
     }
 }

输出结果：

nodeType=3, nodeName=#text, nodeValue= ###此处是Text节点的值（换行+3个制表符）

nodeType=1, nodeName=username, nodeValue=xzc
nodeType=3, nodeName=#text, nodeValue=

nodeType=1, nodeName=password, nodeValue=sdf23223
nodeType=3, nodeName=#text, nodeValue=

nodeType=1, nodeName=birthday, nodeValue=2012-01-23
nodeType=3, nodeName=#text, nodeValue=

nodeType=3, nodeName=#text, nodeValue=

nodeType=1, nodeName=username, nodeValue=误闯
nodeType=3, nodeName=#text, nodeValue=

nodeType=1, nodeName=password, nodeValue=wuchuang3223
nodeType=3, nodeName=#text, nodeValue=

nodeType=1, nodeName=birthday, nodeValue=2002-01-03
nodeType=3, nodeName=#text, nodeValue=

username = xzc, password = sdf23223, birthday = 2012-01-23
username = 误闯, password = wuchuang3223, birthday = 2002-01-03

采用SAX解析XML文件内容到User对象

 package sax.parsing.user;

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

 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.parsers.SAXParser;
 import javax.xml.parsers.SAXParserFactory;

 import org.xml.sax.Attributes;
 import org.xml.sax.SAXException;
 import org.xml.sax.helpers.DefaultHandler;

 public class SaxUtil extends DefaultHandler {

     private List<User> users = new ArrayList<User>();
     private User user;
     private String content;

     @Override
     public void characters(char [] ch, int start, int length) throws SAXException {
         content = new String(ch, start, length);
     }

     /**
      *  xmlns:prefix=uri
      *  qName, prefix:localName
      * @param uri
      *         The Namespace URI, or the empty string if the element has no Namespace URI
      *      or if Namespaceprocessing is not being performed.
      *      如果元素没有命名空间URI、命名空间处理未被开启，则为空字符串
      * @param localName
      *         The local name (without prefix),
      *         or the empty string if Namespace processing is not being performed.
      *         不带前缀的本地名，如果命名空间处理未被开启，则为空字符串
      * @param qName
      *         The qualified name (with prefix),
      *      or the empty string if qualified names are not available.
      *      带前缀的全限定名，如果限定名不可得到，则为空串
      * @param attributes
      *         The attributes attached to the element.
      *      If there are no attributes, it shall be an empty Attributes object.
      *      附加在该元素上的属性，如果元素没有属性，则为空的Attributes对象
      */
     @Override
     public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

         if ("user".equals(localName)) {
             user = new User();
             System.out.println("### " + localName);
             System.out.println("<" + qName + ">");
         }
     }

     @Override
     public void endElement(String uri, String localName, String qName) throws SAXException {

         if ("username".equals(localName))
             user.setUsername(content);

         if ("password".equals(localName))
             user.setPassword(content);

         if ("birthday".equals(localName))
             user.setBirthday(content);

         if ("user".equals(localName))
             users.add(user);
     }

     public List<User> getUsers() {
         return users;
     }

     public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException {

         SAXParserFactory parserFactory = SAXParserFactory.newInstance();
         parserFactory.setNamespaceAware(true); //设置启用命名空间，这样localName才可用
         SAXParser parser = parserFactory.newSAXParser();

         SaxUtil saxUtil = new SaxUtil();

         parser.parse(new File("src/sax/parsing/user/jdbc-params.xml"), saxUtil);
         List<User> userlist = saxUtil.getUsers();

         for (User user : userlist)
             System.out.println(user);
     }

 }

输出结果：

### user
<u:user>
### user
<u:user>
username = xzc, password = sdf23223, birthday = 2012-01-23
username = 误闯, password = wuchuang3223, birthday = 2002-01-03

该实验例子摘自： http://toreking.iteye.com/blog/1669645