1、日期格式化

 Date date=new Date();

 //转换成时间格式12小时制

 SimpleDateFormat df_12=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");

 //转换成时间格式24小时制

 SimpleDateFormat df_24=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

 System.out.println("12小时制时间::"+df_12.format(date));

 System.out.println("24小时制时间::"+df_24.format(date));

 2、过滤文件名非法字符

 private static Pattern FilePattern = Pattern.compile("[\\\\/:*?\"<>|]");

 public static String filenameFilter(String str) {

     return str==null?null:FilePattern.matcher(str).replaceAll("");

 }  

 3、读取文件内容

 public static String readFile(String filePath) throws Exception{

     File file = new File(filePath);

     BufferedReader in = null;

     String result = "";

     String str = "";

     try {

         in = new BufferedReader(new FileReader(file));

         while((str = in.readLine()) != null){

             result += str;

     }

         in.close();

     } catch (Exception e) {

         e.printStackTrace();

     }

     return result;

 }