利用java Api解析XML

核心提示：import java.io.IOException;import java.io.StringReader;import java.util.ArrayList;import java.util.List;import javax.xml.parsers.DocumentBuilder;import javax.xm

import java.io.IOException;
import java.io.StringReader;
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.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

/**
* Usage: You can get a instance of Document from a string of xml.
* This class supply some method to read a document.
*
*/
public class XMLParser {

/**
　* Get a instance of Document from a string of xml.
　*
　* @param xmlStr
　* @return Document
　*/
public static Document parse(String xmlStr) {
　if (xmlStr == null) {
　 return null;
　}
　StringReader reader = new StringReader(xmlStr);
　InputSource source = new InputSource(reader);
　DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
　DocumentBuilder builder = null;

　try {
　 builder = factory.newDocumentBuilder();
　 
　} catch (ParserConfigurationException e) {
　 e.PRintStackTrace();
　}
　if(builder == null){
　 return null;
　}
　Document doc = null;
　try {
　 doc = builder.parse(source);
　} catch (SAXException e) {
　 e.printStackTrace();
　} catch (IOException e) {
　 e.printStackTrace();
　}
　return doc;
}


/**
　* Get Item Value.
　* @param node
　* @return String
　*/
public static String getItemValue(Node node){
　String value = "";
　if(node == null){
　 return null;
　}
　node = node.getFirstChild();
　if(node != null){
　 value = node.getNodeValue();
　}
　return value.trim();
}

/**
　* Get Simple Node's Value
　*
　* @param list
　* @return String
　*/
public static String getSimpleNodeValue(NodeList list){
　String value = "";
　Node node = null;
　if (list != null) {
　 node = list.item(0);
　 value = getItemValue(node);
　}
　return value.trim();
}

/**
　* Get Children.
　* @param list
　* @return List<Node>
　*/
public static List<Node> getChildren(NodeList list){
　List<Node> children = new ArrayList<Node>();
　Node node = null;
　if(list == null){
　 return children;
　}
　for(int i= 0; i< list.getLength(); i++){
　 node = list.item(i);
　 if (node.getNodeType() == Node.ELEMENT_NODE) {
　　children.add(node);
　 }
　}
　return children;
}


/**
　* Get Attribute Value
　* @param node
　* @param name
　* @return String
　* @throws Exception
　*/
public static String getAttributeValue(Node node, String name) throws Exception{
　String value = "";
　if(node == null){
　 throw new Exception("Node is null!");
　}
　NamedNodeMap nnm = node.getAttributes();
　if (nnm == null) {
　 throw new Exception("NamedNodeMap is null!");
　}
　Node item = nnm.getNamedItem(name);
　if (item == null) {
　 throw new Exception("No such attribute.");
　}
　value = item.getNodeValue();
　return value.trim();
}

}