java基础

1.获取Timestamp格式的时间

Date date = new Date();
Timestamp ts = new Timestamp(date.getTime());

 2.遍历一个Map集合

Map<String,Object> map = new HashMap<String,Object>;
Set<String> set = map.keySet();
for(String key:set){
    map.get(key);
}

3.判断一个字符串中是否包含指定字符

String reg = ("['\<>$!%#*&]");
Pattern p = Pattern.compile(reg);
Matcher m = p.matcher(value);
boolean flag = m.find();
//包含返回true 不包含返回false

 4.把String转换成Date

DateFormat df = new SimpleDateFormat("yy-MM-dd HH:mm:ss");
String date = df.format(new Date());
Date currentDate = df.parse(date);