actionconfig.java

java开发购物车+网上书城

package com.xaccp.aj3q8073.controller;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;

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.SAXException;

/**
 * 从配置文件xml中解析出来的 所有类信息并且存储在 HashMap中
 * 
 * @author Administrator
 * 
 */
public class ActionConfig {
	// 利用HashMap以键值对的形式存储path和action
	static HashMap<String, ActionMapping> mapping = new HashMap<String, ActionMapping>();

	public static void putMapping(ActionMapping actionMapping) {
		mapping.put(actionMapping.getPath(), actionMapping);
	}

	/**
	 * 根据放在HashMap中的键取值
	 * 
	 * @param path
	 * @return
	 */
	public static ActionMapping getActionMapping(String servletPath) {
		return mapping.get(servletPath);
	}

	/**
	 * 解析配置文件
	 * 
	 * @param configPath
	 */
	public static void init(String configPath) {
		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
		try {
			DocumentBuilder db = dbf.newDocumentBuilder();
			Document doc = db.parse(new File(configPath));
			Element root = doc.getDocumentElement();
			NodeList list = root.getChildNodes();
			// 从根目录开始找到第一层的ELEMENT_NODE
			for (int i = 0; i < list.getLength(); i++) {
				Node node = list.item(i);
				if (node.getNodeType() != Node.ELEMENT_NODE) {
					continue;
				}
				// 根据节点名称判断
				if (node.getNodeName() == "parament") {
					NodeList lis = node.getChildNodes();
					// 从第一层开始找到第二层的ELEMENT_NODE
					for (int j = 0; j < lis.getLength(); j++) {
						if (!(lis.item(j) instanceof Element)) {
							continue;
						}
						Element action = (Element) lis.item(j);
						// 根据属性名找到它所对应的值
						String path = action.getAttribute("path");
						String className = action.getAttribute("class");
						String methodName = action.getAttribute("method");
						// 判断方法
						if (methodName == null || methodName.length() == 0) {
							methodName = "execute";
						}
						// 根据全定路径加载类
						Class c = Class.forName(className);
						// 调用构造方法分配内存空间生成类的实例
						Object obj = c.newInstance();
						// 把解析到的类信息放进ActionMapping中
						ActionMapping mapping = new ActionMapping();
						mapping.setPath(path);
						mapping.setAction(obj);
						mapping.setMethodName(methodName);
						// 最后再把ActionMapping放进HashMap中
						putMapping(mapping);
					}
				}
			}
		} catch (ParserConfigurationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InstantiationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SAXException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

}