获取当前calendar

Calendar cd = Calendar.getInstance();

//日加7天

cd.add(Calendar.DAY_OF_WEEK,7);

根据日期获取calendar

Calendar cd = Calendar.getInstance();

Date d = new Date();

cd.setTime(d);

cd.add(Calendar.DAY_OF_WEEK,7);

根据字符串获取

DateFormat  df = new SimpleDateFormat("yyyy-MM-dd");

Date d = Df.parse("2014-02-19");

Calendar cd = Calendar.getInstance();

Cd.setTime(d);

cd.add(Calendar.DAY_OF_WEEK,7);

日期加法

cd.add(Calendar.DAY_OF_WEEK,7);

日期减法

cd.add(Calendar.DAY_OF_WEEK,7);

从Date到String

DateFormat df = new SimpleDateFormat("yyyy-MM-dd");

Date d = new Date();

String dstr = Df.format(d);

从String到日期

DateFormat df = new SimpleDateFormat("yyyy-MM-dd");

Date d = df.parse("2014-02-19");

从date到calendar

Calendar cd1 = Calendar.getInstance();

Date sd1 = df.parse(startDate);        

cd1.setTime(sd1);

如：

startDate="2014-02-19";

从calender到Date

Calendar cd1 = Calendar.getInstance();

Date d = cd1.getTime();

格式化Date

DateFormat df = new SimpleDateFormat("yyyy-MM-dd");

String dstr = df.format(new Date());

格式化Calendar

DateFormat df = new SimpleDateFormat("yyyy-MM-dd");

Calendar cd1 = Calendar.getInstance();

String dstr = df.format(cd1.getTime());

格式化日期字符串

DateFormat df = new SimpleDateFormat("yyyy-MM-dd");

Date d = df.parse("2014-02-19");

DateFormat df1 = new SimpleDateFormat("MM-dd");

String dstr2 = df1.format(d);