Java中获取当前时间并格式化

主要有以下方式，代码如下：

1.使用Calendar

Calendar now = Calendar.getInstance();
System.out.println("年：" + now.get(Calendar.YEAR));
System.out.println("月：" + (now.get(Calendar.MONTH) + 1));
System.out.println("日：" + now.get(Calendar.DAY_OF_MONTH));
System.out.println("时：" + now.get(Calendar.HOUR_OF_DAY));
System.out.println("分：" + now.get(Calendar.MINUTE));
System.out.println("秒：" + now.get(Calendar.SECOND));

2.使用Date

Date d = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
System.out.println("当前时间：" + sdf.format(d));

3.使用jdk8新的时间api，LocalDateTime、LocalDate、LocalTime

① jdk8 日期与时间：LocalDateTime

LocalDateTime nowDateTime = LocalDateTime.now();
System.out.println(nowDateTime);
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
System.out.println(dateTimeFormatter.format(nowDateTime));
// 反着使用也可以
System.out.println(nowDateTime.format(dateTimeFormatter));

②jdk8 日期: LocalDate

LocalDate nowDate = LocalDate.now();
System.out.println(nowDate);
DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
System.out.println(dateFormatter.format(nowDate));
// 反着使用也可以
System.out.println(nowDate.format(dateFormatter));

③jdk8 时间：LocalTime

LocalTime nowTime = LocalTime.now();
System.out.println(nowTime);
DateTimeFormatter timeFormatter = DateTimeFormatter.ofPattern("HH:mm:ss");
System.out.println(timeFormatter.format(nowTime));
// 反着使用也可以
System.out.println(nowTime.format(timeFormatter));