Java 对时间的处理

public static void main(String[] args) {
　　SimpleDateFormat format = new SimpleDateFormat("yyyyMM");
　　String str = format.format(new Date());
　　System.out.println(str);
}

 

输出：201312

1.字符串转化为时间

String dateStr = "2014-3-19";

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

Date date = sdf.parse(dateStr);

2.获得时间的年、月、周等信息

Calendar cal = Calendar.getInstance();

int year = cal.get(Calendar.YEAR);//获得年

int month = cal.get(Calendar.MONTH);//获得月

....

 

例子：

public String getperiods(String dataTime,String type){
Date date = null;
Calendar cal = Calendar.getInstance();
try {
// date = DateFormat.getInstance().parse(this.tranDate(dataTime));
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
date = sdf.parse(dataTime);
cal.setTime(date);
if("YEAR".equals(type)){
return cal.get(Calendar.YEAR)+"";
}
if("QUARTER".equals(type)){
// return cal.get(Calendar.YEAR)+"";
}
if("MONTH".equals(type)){
return cal.get(Calendar.YEAR)+""+cal.get(Calendar.MONTH);
}
if("WEEK".equals(type)){
return cal.get(Calendar.YEAR)+""+cal.get(Calendar.WEEK_OF_YEAR);
}
if("DAY".equals(type)){
// return cal.get(Calendar.DAY_OF_YEAR)+"";
return dataTime;
}
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}