java获取时间增加年月日

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

        Date date = new Date();

        String stringDate = sdf.format(date);//date-->String

        System.out.println(stringDate);

        Calendar calendar = new GregorianCalendar();

        calendar.setTime(date);

        calendar.add(Calendar.YEAR, 1); //把日期往后增加一年，整数往后推，负数往前移

        date = calendar.getTime();

        stringDate = sdf.format(date);//date-->String

        System.out.println(stringDate);

        calendar.add(Calendar.MONTH, 1); //把日期往后增加一个月，整数往后推，负数往前移

        date = calendar.getTime();

        stringDate = sdf.format(date);//date-->String

        System.out.println(stringDate);

         calendar.add(Calendar.WEEK_OF_MONTH, 1); //把日期往后增加一周，整数往后推，负数往前移

          date = calendar.getTime();

          stringDate = sdf.format(date);//date-->String

          System.out.println(stringDate);

          calendar.add(Calendar.DAY_OF_MONTH, 1); //把日期往后增加一天，整数往后推，负数往前移

          date = calendar.getTime();

          stringDate = sdf.format(date);//date-->String

          System.out.println(stringDate);

2018-11-0218:35:48

2019-11-0218:35:48

2019-12-0218:35:48

2019-12-0918:35:48

2019-12-1018:35:48