apzl_leasing/src_app/com/amarsoft/aims/util/XMLHelper.java

package com.amarsoft.aims.util;


import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;


import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.io.json.JsonHierarchicalStreamDriver;
import com.thoughtworks.xstream.io.json.JsonWriter;
import com.thoughtworks.xstream.io.xml.DomDriver;

/**
 * xml文件操作类
 * @author yangsong
 * @date 2013/11/07
 */
public class XMLHelper {
	private static final Log log = LogFactory.getLog(XMLHelper.class);

	/**
	 * 保存对象至XML文件
	 * @param file 文件
	 * @param obj 要存储的对象
	 * @param alias xml节点别名映射
	 */
	public static void saveToXMLFile(File file,Object obj,Map<String,Class<?>> alias){
		//保存
		ObjectOutputStream out = null;
		try {
			if(!file.exists())file.createNewFile();
			XStream xstream = new XStream(new DomDriver());
			alias(xstream,alias);
			out = xstream.createObjectOutputStream(new FileWriter(file));
			out.writeObject(obj);
		} catch (IOException e) {
			log.error("保存对象至XML出错",e);
		} finally{
			if(out != null){
				try { out.close(); } catch (IOException e) { } 
			}
		}
	}
	/**
	 * 从文件中读取对象
	 * @param file
	 * @param alias
	 * @return
	 */
	public static Object readFromXMLFile(File file,Map<String,Class<?>> alias){
		XStream xstream = new XStream(new DomDriver());
		alias(xstream,alias);
		ObjectInputStream ois = null;
		Object obj = null;
		try {
			if(!file.exists())file.createNewFile();
			ois = xstream.createObjectInputStream(new FileReader(file));
			obj = ois.readObject();
		} catch (FileNotFoundException e) {
			log.warn("Task记录文件不存在",e);
		} catch (IOException e) {
			log.error("Task记录文件读取出错",e);
		} catch (ClassNotFoundException e) {
			log.error("从文件中读取的java类不存在",e);
		} catch(Exception e){
			log.warn("从文件中没有读取到任何对象",e);
		}finally{
			if(ois!=null){
				try { ois.close(); } catch (IOException e) { }
			}
		}
		return obj;
	}
	/**
	 * 别名
	 * @param xstream
	 * @param alias
	 */
	private static void alias(XStream xstream,Map<String,Class<?>> alias){
		if(alias==null||alias.size()==0)return;
		Iterator<Entry<String, Class<?>>> iterator = alias.entrySet().iterator();
		while(iterator.hasNext()){
			Entry<String, Class<?>> entry = iterator.next();
			xstream.alias(entry.getKey(), entry.getValue());
		}
	}
	
	/**
	 * 把对象转换为JSON字符串
	 * @param obj 需要转换的对象
	 * @param dropRootNode 是否删除根节点
	 * @param alias 别名设置
	 * @return
	 */
	public static String getAsJsonString(Object obj,boolean dropRootNode,Map<String,Class<?>> alias){
		String strJson = null;
		JsonHierarchicalStreamDriver streamDriver = null;
		if(dropRootNode){	//如果需要删除根节点，则重写方法
			streamDriver = new JsonHierarchicalStreamDriver() {
				public HierarchicalStreamWriter createWriter(Writer out) {
					return new JsonWriter(out, JsonWriter.DROP_ROOT_MODE);
				}
			};
		}else{
			streamDriver = new JsonHierarchicalStreamDriver();
		}
		XStream xstream = new XStream(streamDriver);
		xstream.setMode(XStream.NO_REFERENCES);
//		xstream.setMode(XStream.ID_REFERENCES);
		alias(xstream,alias);
		strJson = xstream.toXML(obj);
		return strJson;
	}
	/**
	 * 把对象转为XML字串
	 * @param obj
	 * @param alias
	 * @return
	 */
	public static String getAsXMLString(Object obj,Map<String,Class<?>> alias){
		String strJson = null;
		XStream xstream = new XStream(new DomDriver());
		xstream.setMode(XStream.NO_REFERENCES);
//		xstream.setMode(XStream.ID_REFERENCES);
		alias(xstream,alias);
		strJson = xstream.toXML(obj);
		return strJson;
	}
	/**
	 * 把对象转换为JSON字符串
	 * @param obj
	 * @return
	 */
	public static String getAsJsonString(Object obj){
		return getAsJsonString(obj,true,null);
	}
	/**
	 * 创建一个XPath的XMLFile对象
	 * @param file
	 * @param xPathExpr
	 * @return
	 */
	public static XMLParse createXMLFile(File file){
		return new XMLParse(file);
	}
	/**
	 * 使用xml字串构建一个xmlParse对象
	 * @param xmlString
	 * @return
	 */
	public static XMLParse createXMLFile(String xmlString){
		return new XMLParse(xmlString);
	}
	/**
	 * 从XML文件中创建出列表对象列表
	 * @param clazz 要创建的类名
	 * @param fileName 文件名
	 * @param create 如果文件不存在，是否创建文件
	 * @param alias 读取别名
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public static <T> List<T> createObjectsFromFile(Class<T> clazz,String fileName,boolean create,Map<String,Class<?>> alias){
		File file = new File(fileName);
		if(!file.exists()&&create){
			try {
				file.createNewFile();
			} catch (IOException e) {
				log.error("创建新文件失败",e);
			}
		}
		
		List<T> objectList = (List<T>)XMLHelper.readFromXMLFile(file, alias);
		if(objectList==null) objectList = new ArrayList<T>();
		return objectList;
	}
	
	/**
	 * 
	 * 保存对象列表
	 * @param clazz 类名
	 * @param fileName 文件名
	 * @param objectList 对象列表
	 * @param alias 写入时的别名
	 * @param comparator 排序接口
	 */
	public static <T> void saveObjectsToXMLFile(Class<T> clazz,String fileName,List<T> objectList,Map<String,Class<?>> alias,Comparator<T> comparator){
		//如果传入排序接口，则进行一次排序操作
		if(comparator!=null){
			Collections.sort(objectList,comparator);
		}
		//保存
		File file = new File(fileName);
		if(!file.exists()){
			try {
				file.createNewFile();
			} catch (IOException e) {
				log.error("创建新文件失败",e);
			}
		}		
		XMLHelper.saveToXMLFile(file, objectList, alias);
	}
	
}