Date processing

Before Java 8, it was not very convenient to operate the date. Some places need to be programmed and implemented by yourself. In Java 8, many classes about date processing are added under the java.time package. Through these classes, developers can operate the date more easily. These classes are all final decorated and thread safe.

Class LocalDate

LocalDate class can only operate date related data, not time

//LocalDate class
		//LocalDate class can only operate on date related data without time
		
		LocalDate date1 = LocalDate.now();
		System.out.println(date1); //2019-03-11

		int year = date1.getYear();
		int month = date1.getMonthValue();
		int day = date1.getDayOfMonth();
		
		
		//format date
		String s1 = date1.format(DateTimeFormatter.ofPattern("YYYY year MM month DD day"));
		System.out.println(s1);
		
		
		//Judgement of leap year
		boolean leap = date1.isLeapYear();
		
		//How many days to get the month
		int len = date1.lengthOfMonth();
		System.out.println(len);
		

Class LocalTime

The LocalTime class can only operate on time-related data, excluding dates

LocalTime time1 = LocalTime.now().withNano(0);
		System.out.println(time1);
		
		//Setup time
		LocalTime time2 = LocalTime.of(6, 30, 20);
		System.out.println(time2);
		
		
		LocalTime time3 = LocalTime.parse("18:20:20");
		System.out.println(time3);

LocalDateTime class

The LocalDateTime class can process date and time data

//LocalDateTime class
		LocalDateTime time = LocalDateTime.now();
		System.out.println("The current time is:"+time);

Duration and Period

The Duration class is used to get the time difference between two localtimes
The Period class is used to get the date when two localdates differ

//Calculate the time difference between two localtimes
		LocalTime time7 = LocalTime.of(7, 20);
		LocalTime time8 = LocalTime.of(7, 30);
		Duration duration = Duration.between(time7, time8);
		System.out.println("The number of time seconds between the two is:"+duration.getSeconds());

//How many years, months and days have passed since the founding of the people's Republic of China
		//Founding date
		LocalDate begin = LocalDate.of(1949, 10, 1);
		//Today's date
		LocalDate end = LocalDate.now();
		System.out.println("The motherland has been established");
		System.out.println(Period.between(begin, end).getYears()+"year");
		System.out.println(Period.between(begin, end).getMonths()+"month");
		System.out.println(Period.between(begin, end).getDays()+"day");