Java时间处理第三方包Joda Time使用详解

<dependency>
    <groupId>joda-time</groupId>
    <artifactId>joda-time</artifactId>
    <version>2.3</version>
</dependency>

Date date = new Date();

DateTime dateTime = new DateTime();

DateTime dateTime = new DateTime(2016, 10, 01, 00, 00);

Date date = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String dateStr = sdf.format(date);

DateTime dateTime = new DateTime();
String dateTimeStr = dateTime.toString("yyyy-MM-dd HH:mm:ss");

DateTimeFormatter dtf = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss");
String dateTimeStr = dtf.print(dateTime);

String dateStr = "2016-09-22";
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
try {
    Date date = sdf.parse(dateStr);
    } catch (ParseException e) {
        e.printStackTrace();
    }
DateTimeFormatter dtf = DateTimeFormat.forPattern("yyyy-MM-dd");
DateTime dateTime = dtf.parseDateTime(dateStr);

Date today = new Date();
Calendar calendar = Calendar.getInstance();
calendar.setTime(today); // 设置日历
calendar.add(Calendar.DAY_OF_MONTH, -40); // 将日历往回翻40天
Date beforeDay = calendar.getTime(); // 日历返回日期

DateTime today = new DateTime();
DateTime beforeDay = today.minusDays(40);

int diffDays = (int) ((today.getTime() - beforeDay.getTime()) / (24*60*60*1000));

int diffDays = Days.daysBetween(yesterday, today).getDays();

int diffMonths = Months.monthsBetween(yesterday, today).getMonths();

// Date to DateTime
Date date = new Date();
DateTime dateTime = new DateTime(date);
// DateTime to Date
Date date2 = dateTime.toDate();
// Calendar to DateTime
Calendar calender = Calendar.getInstance();
DateTime dateTime2 =  new DateTime(calender);
// DateTime to Calendar
Calendar calendar2 = dateTime.toCalendar(Locale.CHINA);