JAVA快速功能

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;
}