java获取缺文件名和扩展名

/**
     * 获取短文件名,不带扩展名
     * @param fileName
     * @return
     */
    public static String getShortName(String fileName){
    	if(fileName != null && fileName.length()>0 && fileName.lastIndexOf(".")>-1){
    		return fileName.substring(0, fileName.lastIndexOf("."));
    	} 
    	return fileName;
    }
    
    /**
     * 获取扩展名,带点
     * @param fileName
     * @return
     */
    public static String getExtention(String fileName){
    	if(fileName!=null && fileName.length()>0 && fileName.lastIndexOf(".")>-1){
	    	return fileName.substring(fileName.lastIndexOf("."));
    	}
    	return "";
    }
    
    public static void main(String[] args) {
    	System.out.println(FileUtil.getShortName("aaa.xlsx"));
    	System.out.println(FileUtil.getShortName("aaa"));
    	System.out.println(FileUtil.getShortName("."));
    	System.out.println(FileUtil.getShortName(".xlsx"));
    	
    	System.out.println(FileUtil.getExtention("aaa.xlsx"));
    	System.out.println(FileUtil.getExtention("aaa"));
    	System.out.println(FileUtil.getExtention("."));
    	System.out.println(FileUtil.getExtention(".xlsx"));
    }