java取得当前日期增加一天或多天

代码如下：

SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd");
Calendar c = Calendar.getInstance();
System.out.println("当前日期:"+sf.format(c.getTime()));
c.add(Calendar.DAY_OF_MONTH, 1);
System.out.println("增加一天后日期:"+sf.format(c.getTime()));
//打印结果
//当前日期：         2013-06-18
//增加一天后日期 ：   2013-06-19

Java Calendar获取年、月、日、时间

 Calendar c = Calendar.getInstance(TimeZone.getTimeZone("GMT+08:00"));    //获取东八区时间

int year = c.get(Calendar.YEAR);    //获取年
int month = c.get(Calendar.MONTH) + 1;   //获取月份，0表示1月份
int day = c.get(Calendar.DAY_OF_MONTH);    //获取当前天数
int first = c.getActualMinimum(c.DAY_OF_MONTH);    //获取本月最小天数
int last = c.getActualMaximum(c.DAY_OF_MONTH);    //获取本月最大天数
int time = c.get(Calendar.HOUR_OF_DAY);       //获取当前小时
int min = c.get(Calendar.MINUTE);          //获取当前分钟
int xx = c.get(Calendar.SECOND);          //获取当前秒



SimpleDateFormat s=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String curDate = s.format(c.getTime());  //当前日期
System.out.println("当前时间："+year + "-" + month + "-"+ day + " "+time + ":" + min +":" + xx);
System.out.println("第一天和最后天：" + first +"," + last);
System.out.println("当前日期curDate====：" + curDate);

输出结果：

当前时间：2012-9-25 22:50:54 第一天和最后天：1,30

当前日期curDate：2012-09-25 22:50:54

Calendar的计算

c.add(Calendar.YEAR, 1);
c.add(Calendar.MONTH, 1);
c.add(Calendar.DAY_OF_MONTH, 1);
int year2 = c.get(Calendar.YEAR);
int month2 = c.get(Calendar.MONTH) + 1;
int day2 = c.get(Calendar.DAY_OF_MONTH);
int firstD = c.getActualMinimum(c.DAY_OF_MONTH);
int lastD = c.getActualMaximum(c.DAY_OF_MONTH);
System.out.println("当前时间："+year2 + "-" + month2 + "-"+ day2 + " "+time + ":" + min +":" + xx);
System.out.println("第一天和最后天：" + firstD +"," + lastD);

输出结果：

当前时间：2013-10-26 23:4:3 第一天和最后天：1,31

获取上个月的年、月、日

Calendar c=Calendar.getInstance();
c.add(Calendar.MONTH, -1);//上个月
SimpleDateFormat s=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String year=String.valueOf(c.get(Calendar.YEAR));
String topDay = String.valueOf(c.getActualMinimum(Calendar.DAY_OF_MONTH));
String lastDay = String.valueOf(c.getActualMaximum(Calendar.DAY_OF_MONTH));

//上个月
String lastMonth=String.valueOf(c.get(Calendar.MONTH)+1).length()==2?String.valueOf(c.get(Calendar.MONTH)+1):"0"+String.valueOf(c.get(Calendar.MONTH)+1);
String topDayMonth=year+"-"+lastMonth+"-"+"01" + " 00:00:00";
String lastDayMonth = year+"-"+lastMonth+"-"+lastDay+ " 23:59:59";
System.out.println("###year:" + year);
System.out.println("###last month:" + lastMonth);
System.out.println("###topday:" + topDayMonth);
System.out.println("###lastday:" + lastDayMonth);

输出结果

###year:2013

###last month:04

###topday:2013-04-01 00:00:00

###lastday:2013-04-30 23:59:59

转自 http://hi.baidu.com/zzm_2007/item/3b967b1cd1586e4e2b3e2258

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class DateTest {
    public static Date geLastWeekMonday(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(getThisWeekMonday(date));
        cal.add(Calendar.DATE, -7);
        return cal.getTime();
    }

    public static Date getThisWeekMonday(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        // 获得当前日期是一个星期的第几天
        int dayWeek = cal.get(Calendar.DAY_OF_WEEK);
        if (1 == dayWeek) {
            cal.add(Calendar.DAY_OF_MONTH, -1);
        }
        // 设置一个星期的第一天，按中国的习惯一个星期的第一天是星期一
        cal.setFirstDayOfWeek(Calendar.MONDAY);
        // 获得当前日期是一个星期的第几天
        int day = cal.get(Calendar.DAY_OF_WEEK);
        // 根据日历的规则，给当前日期减去星期几与一个星期第一天的差值
        cal.add(Calendar.DATE, cal.getFirstDayOfWeek() - day);
        return cal.getTime();
    }

    public static Date getNextWeekMonday(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(getThisWeekMonday(date));
        cal.add(Calendar.DATE, 7);
        return cal.getTime();
    }

    public static void main(String[] args) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        try {
            Date date = sdf.parse("2017-09-10");
            System.out.println("今天是" + sdf.format(date));
            System.out.println("上周一" + sdf.format(geLastWeekMonday(date)));
            System.out.println("本周一" + sdf.format(getThisWeekMonday(date)));
            System.out.println("下周一" + sdf.format(getNextWeekMonday(date)));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

输出结果：

今天是2017-09-10
上周一2017-08-28
本周一2017-09-04
下周一2017-09-11