public List<Email> loadEmail(){
		List<Email> emailList=new ArrayList<Email>();
		File filePath=new File(PERSISTENCE_PATH);
		if(filePath.isDirectory()){
			String[] fileList=filePath.list();
			if(fileList.length==0){
				//没有文件
				return null;
			}
			for (int i = 0; i < fileList.length; i++) {
				File file=new File(PERSISTENCE_PATH+fileList[i]);
				logger.debug("persistence:加载文件"+file.getName());
				ObjectInputStream ois=null;
				try {
					ois=new ObjectInputStream(new FileInputStream(file));
					emailList.add((Email)ois.readObject());
				} catch (FileNotFoundException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				} catch (ClassNotFoundException e) {
					e.printStackTrace();
				}finally{
					if(ois!=null){
						try {
							ois.close();
						} catch (IOException e) {
							e.printStackTrace();
						}
					}
				}
				
			}
		}else {
			logger.error("EmailPersistence.loadEmail error");
		}
		return emailList;
	}